glinski_stemflow
tested hypotheses
Test to see whether field observations of stemflow concentrations are greater that forest throughfall concentrations (or vice-versa). Samples are paired across 3 locations and 18 different sampling dates. Therefore 54 observations for each of 32 chemicals. However, many samples are non-detected.
Non-parametric Wilcoxon Rank Sum test implemented. Permutation tests also possible. Test requiring distribution assumptions (e.g., t-test) not practical due to non-detects and data skewness.
This page is published at: http://rpubs.com/puruckertom/glinski_stemflow
things to do
- implement permutation tests
- test all 32 chemicals at once rather than one at a time
- effects estimation approaches
- signs versus time
- signs versus rainfall (need cumulative rainfall)
- signs versus volume
general configuration
Install and load supporting libraries.
## nodename
## "stp-air"## [1] "R version 3.3.1 (2016-06-21)"## Warning: package 'knitr' was built under R version 3.3.2## Warning: package 'ggplot2' was built under R version 3.3.2## [1] "list of loaded packages: "## [1] "ggplot2" "knitr" "dplyr" "rmarkdown" "stats"
## [6] "graphics" "grDevices" "utils" "datasets" "methods"
## [11] "base"import experimental exposure and dehydration data
Load csv file with experimental dehydration data. The below may return false but still be OK if rstudio does not have privileges to data directory (e.g., attached drive).
## [1] "Root directory location: /Users/puruckertom/git/glinski_stemflow/"## [1] "check to see if R can access files OK: TRUE"tifton data structure
Check out structure of imported data sets.
summary(tifton)## Type Site Date Compound
## SF:1728 Min. : 1.000 1/17/2016 : 512 2-Phenylphenol: 228
## TF:1728 1st Qu.: 3.000 10/8/2015 : 512 Acetochlor : 228
## TP:3840 Median : 4.000 11/8/2015 : 512 Alachlor : 228
## Mean : 5.105 12/17/2015: 512 Anthraquione : 228
## 3rd Qu.: 7.000 5/22/2015 : 512 Atrazine : 228
## Max. :10.000 6/23/2015 : 512 Benfluralin : 228
## (Other) :4224 (Other) :5928
## Conc Volume
## Min. :0.010 Min. : 0.132
## 1st Qu.:0.170 1st Qu.: 2.000
## Median :0.250 Median : 5.000
## Mean :0.421 Mean : 9.266
## 3rd Qu.:0.380 3rd Qu.:16.000
## Max. :9.540 Max. :25.000
## NA's :6504 NA's :4416colnames(tifton)## [1] "Type" "Site" "Date" "Compound" "Conc" "Volume"chems <- unique(tifton$Compound)
chems## [1] Metolachlor Tebuconazole
## [3] 2-Phenylphenol Flutolanil
## [5] Biphenyl Atrazine
## [7] Metalaxyl Acetochlor
## [9] Alachlor Anthraquione
## [11] Endosulfan Lactone DEA
## [13] Endosulfan ether Cyprodinil
## [15] Triadimefon Chlorothalonil
## [17] Diphenylamine Fipronil
## [19] Myclobutanil Oxyfluorfen
## [21] Bifenthrin Fludioxonil
## [23] Endosulfan sulfate Ethalfluralin
## [25] Pendimethalin Benfluralin
## [27] Diazinon Malathion
## [29] Oxadiazon Piperonyl butoxide
## [31] Propyzamide THPI (Tetrahydrophthalimide)
## 32 Levels: 2-Phenylphenol Acetochlor Alachlor Anthraquione ... Triadimefonmedia <- unique(tifton$Type)
media## [1] TP SF TF
## Levels: SF TF TP#coerce concentrations to numeric because NAs
tifton$Conc <- as.numeric(tifton$Conc)
min(tifton$Conc,na.rm=TRUE)## [1] 0.01max(tifton$Conc,na.rm=TRUE)## [1] 9.54wilcox stat testing
Run Wilcoxon rank sum test on throughfall versus stemflow for each individual chemical that has detected values. There are three different commands in R that calculate the Wilcoxon signed-rank test; wilcox.test, wilcox.exact, and wilcoxsign_test. They will each yield a different p-value.
The nonparametric Wilcoxon signed-rank test seems to be the most appropriate test for these data. There are two different methods to calculate the signed-rank test. The first is by Wilcoxon (1945), who discards any tied data and then calculates the signed ranks. The second method incorporates tied values in the ranking procedure (see J.W. Pratt, 1959, Remarks on zeros and ties in the Wilcoxon signed rank procedure: Journal of the American Statistical Association, Vol. 54, No. 287, pp. 655-667). There are two commands in R that calculate the original method by Wilcoxon, wilcox.test and wilcoxsign_test (make sure to include the argument “zero.method = c(”Wilcoxon“)”). There are two other commands in R that incorporate ties in the signed-rank test, wilcox.exact and wilcoxsign_test (make sure to include the argument“zero.method = c(”Pratt“)”).
- wilcox.test() in the stats package This function automatically switches to using a Normal approximation when there are ties in the data:
wilcox.test(x, y, paired=TRUE)$p.value
(You can suppress the warning (due to ties) by specifying the argument ‘exact=FALSE’.)
This function also uses a continuity correction unless told not to:
wilcox.test(x, y, paired=TRUE, correct=FALSE)$p.value
- wilcox.exact() in pkg exactRankTests This function can handle ties (using the “Wilcoxon” method) with an ‘exact’ calculation:
wilcox.exact(x, y, paired=TRUE)$p.value
If we want the Normal approximation:
wilcox.exact(x, y, paired=TRUE, exact=FALSE)$p.value
- wilcoxsign_test() in pkg coin This is the most comprehensive of these functions. It is also the only one that offers the “Pratt” method of handling ties. It will default to this method and a Normal approximation:
pvalue(wilcoxsign_test(x ~ y))
pvalue(wilcoxsign_test(x ~ y, zero.method=“Pratt”, distribution=“asympt”))
You can get the results from wilcox.exact() with
pvalue(wilcoxsign_test(x ~ y, zero.method=“Wilcoxon”, distribution=“asympt”))
and
pvalue(wilcoxsign_test(x ~ y, zero.method=“Wilcoxon”, dist=“exact”))
For the moment we are using wilcox.test with ties (paired = TRUE, alternative = ‘greater’, exact = FALSE) but the test is not being run unless there are at least 4 detected values for a chemical.
chemical level analyses
for(chem in chems){
print('=======================================================')
print(chem)
chem_data <- tifton[which(tifton$Compound==chem),]
chem_sf <- chem_data[which(chem_data$Type=='SF'),]
chem_tf <- chem_data[which(chem_data$Type=='TF'),]
#merge on site, date, compound
chem_merge <- merge(chem_sf,chem_tf,by=c("Compound","Site","Date"))
#conc.x is sf; conc.y is tf
#we want to test if stemflow is greater than throughfall (x > y)
x_nas <- sum(is.na(chem_merge$Conc.x))
y_nas <- sum(is.na(chem_merge$Conc.y))
x_n <- length(is.na(chem_merge$Conc.x))
y_n <- length(is.na(chem_merge$Conc.y))
x_dets <- x_n - x_nas
y_dets <- y_n - y_nas
if(x_dets>0){
if(x_nas==0){
x_min <- min(chem_merge$Conc.x,na.rm=TRUE)
}else{
x_min=0
}
x_max <- max(chem_merge$Conc.x,na.rm=TRUE)
}else{
x_min <- 0
x_max <- 0
}
if(y_dets>0){
if(y_nas==0){
y_min <- min(chem_merge$Conc.y,na.rm=TRUE)
}else{
y_min=0
}
y_max <- max(chem_merge$Conc.y,na.rm=TRUE)
}else{
y_min <- 0
y_max <- 0
}
#colnames(chem_merge)
print(paste(chem,'stemflow detection frequency = ',x_dets,'/',x_n))
print(paste(chem,'stemflow concentration range =(',x_min,',',x_max,')'))
print(paste(chem,'throughfall detection frequency = ',y_dets,'/',y_n))
print(paste(chem,'throughfall concentration range =(',y_min,',',y_max,')'))
#change NAs to zeroes for conparisons and the Wilcox test
chem_merge$Conc.x[is.na(chem_merge$Conc.x)] <- 0
chem_merge$Conc.y[is.na(chem_merge$Conc.y)] <- 0
n_comparisons <- length(chem_merge$Conc.x)
n_tf_greater <- sum(chem_merge$Conc.y > chem_merge$Conc.x)
n_ties <- sum(chem_merge$Conc.y == chem_merge$Conc.x)
n_sf_greater <- sum(chem_merge$Conc.x > chem_merge$Conc.y)
comparisons <- paste('(throughfall_greater, ties, stemflow_greater) = ('
,n_tf_greater,',',n_ties,',',n_sf_greater,')')
print(comparisons)
if((x_dets+y_dets)>4){
print(knitr::kable(chem_merge))
chem_wilcox <- wilcox.test(chem_merge$Conc.x, chem_merge$Conc.y,
alternative = 'less', paired = TRUE, exact = FALSE)
max_conc <- max(x_max,y_max)
max_conc_vector <- seq(0,max_conc,20)
print(chem_wilcox)
plot(chem_merge$Conc.x, chem_merge$Conc.y,xlim=c(0,max_conc),ylim=c(0,max_conc),
xlab='Stemflow Concentration',ylab='Throughfall Concentration',
main=paste(chem,'(WRS p-value = ',round(chem_wilcox$p.value,4),')'),
sub = comparisons)
abline(0,1,col='red')
}else{
print(paste(chem,'does not have enough detected values for wilcox test'))
}
}## [1] "======================================================="
## [1] "Metolachlor"
## [1] "Metolachlor stemflow detection frequency = 45 / 54"
## [1] "Metolachlor stemflow concentration range =( 0 , 2.63 )"
## [1] "Metolachlor throughfall detection frequency = 40 / 54"
## [1] "Metolachlor throughfall concentration range =( 0 , 2.98 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 17 , 5 , 32 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## ------------ ----- ----------- ------- ---------- --------- ------- ---------- ---------
## Metolachlor 3 1/17/2016 SF 0.2700000 25.000 TF 0.0000000 10.000
## Metolachlor 3 10/8/2015 SF 0.2500000 20.000 TF 0.0800000 3.750
## Metolachlor 3 11/8/2015 SF 0.0000000 NA TF 0.0000000 2.000
## Metolachlor 3 12/17/2015 SF 0.0000000 25.000 TF 0.0000000 12.000
## Metolachlor 3 3/18/2015 SF 0.2272727 0.132 TF 0.7559055 0.635
## Metolachlor 3 4/16/2015 SF 0.0000000 0.670 TF 0.0000000 3.000
## Metolachlor 3 5/1/2015 SF 0.0000000 16.000 TF 0.3200000 1.000
## Metolachlor 3 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Metolachlor 3 6/10/2015 SF 0.6300000 15.000 TF 1.4000000 4.000
## Metolachlor 3 6/23/2015 SF 0.6900000 NA TF 1.6700000 NA
## Metolachlor 3 7/10/2015 SF 0.7400000 8.500 TF 0.6300000 3.000
## Metolachlor 3 7/17/2015 SF 0.1400000 NA TF 0.9500000 NA
## Metolachlor 3 7/2/2015 SF 0.0000000 NA TF 1.1300000 1.000
## Metolachlor 3 7/30/2015 SF 0.4600000 20.000 TF 0.4700000 4.000
## Metolachlor 3 8/13/2015 SF 0.3400000 13.000 TF 0.4700000 4.000
## Metolachlor 3 8/27/2015 SF 0.2800000 17.000 TF 0.2900000 4.000
## Metolachlor 3 9/17/2015 SF 0.0000000 2.500 TF 0.6400000 3.000
## Metolachlor 3 9/3/2015 SF 0.7272727 0.220 TF 0.0289855 0.690
## Metolachlor 4 1/17/2016 SF 0.1600000 25.000 TF 0.0000000 10.000
## Metolachlor 4 10/8/2015 SF 0.3700000 25.000 TF 0.0000000 4.000
## Metolachlor 4 11/8/2015 SF 0.2400000 15.000 TF 0.0000000 2.000
## Metolachlor 4 12/17/2015 SF 0.3500000 25.000 TF 0.0000000 12.000
## Metolachlor 4 3/18/2015 SF 0.4100000 1.000 TF 0.9090909 0.440
## Metolachlor 4 4/16/2015 SF 0.3600000 13.000 TF 0.7100000 2.000
## Metolachlor 4 5/1/2015 SF 0.8000000 5.000 TF 0.2700000 4.500
## Metolachlor 4 5/22/2015 SF 1.3200000 25.000 TF 0.5300000 6.000
## Metolachlor 4 6/10/2015 SF 0.9500000 25.000 TF 0.5400000 4.000
## Metolachlor 4 6/23/2015 SF 1.7500000 NA TF 0.1000000 NA
## Metolachlor 4 7/10/2015 SF 0.4300000 25.000 TF 0.0000000 4.000
## Metolachlor 4 7/17/2015 SF 0.6600000 NA TF 0.0100000 NA
## Metolachlor 4 7/2/2015 SF 0.5481481 0.675 TF 0.0300000 4.000
## Metolachlor 4 7/30/2015 SF 0.5700000 25.000 TF 0.2700000 6.000
## Metolachlor 4 8/13/2015 SF 0.4200000 20.000 TF 0.2500000 6.000
## Metolachlor 4 8/27/2015 SF 0.2900000 25.000 TF 0.1400000 4.750
## Metolachlor 4 9/17/2015 SF 0.6400000 25.000 TF 0.5500000 3.000
## Metolachlor 4 9/3/2015 SF 0.3703704 0.540 TF 0.0363636 0.550
## Metolachlor 7 1/17/2016 SF 0.2600000 25.000 TF 0.0000000 7.000
## Metolachlor 7 10/8/2015 SF 0.4100000 17.000 TF 0.0000000 5.000
## Metolachlor 7 11/8/2015 SF 0.4100000 5.000 TF 0.1200000 1.000
## Metolachlor 7 12/17/2015 SF 0.3300000 25.000 TF 0.0000000 9.000
## Metolachlor 7 3/18/2015 SF 0.0000000 0.230 TF 0.1600000 0.550
## Metolachlor 7 4/16/2015 SF 0.4500000 12.500 TF 0.3400000 2.000
## Metolachlor 7 5/1/2015 SF 1.1600000 20.000 TF 1.0900000 5.000
## Metolachlor 7 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Metolachlor 7 6/10/2015 SF 0.3600000 20.000 TF 2.9800000 5.000
## Metolachlor 7 6/23/2015 SF 2.2000000 NA TF 2.7800000 NA
## Metolachlor 7 7/10/2015 SF 0.0800000 7.000 TF 0.5800000 2.000
## Metolachlor 7 7/17/2015 SF 0.5300000 NA TF 0.9800000 NA
## Metolachlor 7 7/2/2015 SF 1.5200000 3.000 TF 1.4100000 1.500
## Metolachlor 7 7/30/2015 SF 0.9300000 20.000 TF 0.3800000 3.500
## Metolachlor 7 8/13/2015 SF 0.8000000 15.000 TF 0.2900000 4.000
## Metolachlor 7 8/27/2015 SF 0.8500000 25.000 TF 0.3600000 4.000
## Metolachlor 7 9/17/2015 SF 2.6300000 14.000 TF 0.1300000 2.000
## Metolachlor 7 9/3/2015 SF 0.4018547 0.647 TF 0.2068966 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 730, p-value = 0.8798
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Tebuconazole"
## [1] "Tebuconazole stemflow detection frequency = 15 / 54"
## [1] "Tebuconazole stemflow concentration range =( 0 , 1.64 )"
## [1] "Tebuconazole throughfall detection frequency = 43 / 54"
## [1] "Tebuconazole throughfall concentration range =( 0 , 1.8 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 35 , 10 , 9 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## ------------- ----- ----------- ------- ---------- --------- ------- ---------- ---------
## Tebuconazole 3 1/17/2016 SF 0.0000000 25.000 TF 0.1800000 10.000
## Tebuconazole 3 10/8/2015 SF 0.0000000 20.000 TF 0.2200000 3.750
## Tebuconazole 3 11/8/2015 SF 0.0000000 NA TF 0.0000000 2.000
## Tebuconazole 3 12/17/2015 SF 0.0000000 25.000 TF 0.0000000 12.000
## Tebuconazole 3 3/18/2015 SF 0.0000000 0.132 TF 0.0000000 0.635
## Tebuconazole 3 4/16/2015 SF 0.0000000 0.670 TF 0.0000000 3.000
## Tebuconazole 3 5/1/2015 SF 0.0000000 16.000 TF 0.1900000 1.000
## Tebuconazole 3 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Tebuconazole 3 6/10/2015 SF 0.0000000 15.000 TF 0.1800000 4.000
## Tebuconazole 3 6/23/2015 SF 0.0000000 NA TF 0.1800000 NA
## Tebuconazole 3 7/10/2015 SF 0.0000000 8.500 TF 0.2900000 3.000
## Tebuconazole 3 7/17/2015 SF 0.0000000 NA TF 0.5900000 NA
## Tebuconazole 3 7/2/2015 SF 0.0000000 NA TF 0.4900000 1.000
## Tebuconazole 3 7/30/2015 SF 0.0000000 20.000 TF 0.2100000 4.000
## Tebuconazole 3 8/13/2015 SF 0.0000000 13.000 TF 0.3000000 4.000
## Tebuconazole 3 8/27/2015 SF 1.6400000 17.000 TF 0.6500000 4.000
## Tebuconazole 3 9/17/2015 SF 0.0000000 2.500 TF 0.4200000 3.000
## Tebuconazole 3 9/3/2015 SF 0.0000000 0.220 TF 0.3333333 0.690
## Tebuconazole 4 1/17/2016 SF 0.0000000 25.000 TF 0.1800000 10.000
## Tebuconazole 4 10/8/2015 SF 0.3300000 25.000 TF 0.3400000 4.000
## Tebuconazole 4 11/8/2015 SF 0.0000000 15.000 TF 0.3500000 2.000
## Tebuconazole 4 12/17/2015 SF 0.2900000 25.000 TF 0.2400000 12.000
## Tebuconazole 4 3/18/2015 SF 0.0000000 1.000 TF 0.0000000 0.440
## Tebuconazole 4 4/16/2015 SF 0.0000000 13.000 TF 0.0000000 2.000
## Tebuconazole 4 5/1/2015 SF 0.0000000 5.000 TF 0.2800000 4.500
## Tebuconazole 4 5/22/2015 SF 0.2700000 25.000 TF 0.2200000 6.000
## Tebuconazole 4 6/10/2015 SF 0.0000000 25.000 TF 0.2000000 4.000
## Tebuconazole 4 6/23/2015 SF 0.2400000 NA TF 0.2100000 NA
## Tebuconazole 4 7/10/2015 SF 0.0000000 25.000 TF 0.1900000 4.000
## Tebuconazole 4 7/17/2015 SF 0.0000000 NA TF 0.3500000 NA
## Tebuconazole 4 7/2/2015 SF 0.0000000 0.675 TF 0.2300000 4.000
## Tebuconazole 4 7/30/2015 SF 0.2500000 25.000 TF 0.2700000 6.000
## Tebuconazole 4 8/13/2015 SF 0.0000000 20.000 TF 0.2600000 6.000
## Tebuconazole 4 8/27/2015 SF 0.6500000 25.000 TF 1.8000000 4.750
## Tebuconazole 4 9/17/2015 SF 0.3300000 25.000 TF 0.7900000 3.000
## Tebuconazole 4 9/3/2015 SF 0.5370370 0.540 TF 0.7454545 0.550
## Tebuconazole 7 1/17/2016 SF 0.2200000 25.000 TF 0.0000000 7.000
## Tebuconazole 7 10/8/2015 SF 0.4700000 17.000 TF 0.2100000 5.000
## Tebuconazole 7 11/8/2015 SF 0.0000000 5.000 TF 0.2600000 1.000
## Tebuconazole 7 12/17/2015 SF 0.0000000 25.000 TF 0.0000000 9.000
## Tebuconazole 7 3/18/2015 SF 0.0000000 0.230 TF 0.0000000 0.550
## Tebuconazole 7 4/16/2015 SF 0.0000000 12.500 TF 0.1600000 2.000
## Tebuconazole 7 5/1/2015 SF 0.0000000 20.000 TF 0.2100000 5.000
## Tebuconazole 7 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Tebuconazole 7 6/10/2015 SF 0.0000000 20.000 TF 0.2600000 5.000
## Tebuconazole 7 6/23/2015 SF 0.0000000 NA TF 0.1900000 NA
## Tebuconazole 7 7/10/2015 SF 0.3600000 7.000 TF 0.2400000 2.000
## Tebuconazole 7 7/17/2015 SF 0.0000000 NA TF 0.2800000 NA
## Tebuconazole 7 7/2/2015 SF 0.0000000 3.000 TF 0.3700000 1.500
## Tebuconazole 7 7/30/2015 SF 0.0000000 20.000 TF 0.2100000 3.500
## Tebuconazole 7 8/13/2015 SF 0.2400000 15.000 TF 0.3200000 4.000
## Tebuconazole 7 8/27/2015 SF 1.2800000 25.000 TF 0.6500000 4.000
## Tebuconazole 7 9/17/2015 SF 0.0000000 14.000 TF 0.2600000 2.000
## Tebuconazole 7 9/3/2015 SF 0.6800618 0.647 TF 0.6206897 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 160.5, p-value = 4.825e-05
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "2-Phenylphenol"
## [1] "2-Phenylphenol stemflow detection frequency = 15 / 54"
## [1] "2-Phenylphenol stemflow concentration range =( 0 , 0.68 )"
## [1] "2-Phenylphenol throughfall detection frequency = 23 / 54"
## [1] "2-Phenylphenol throughfall concentration range =( 0 , 0.545454545 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 21 , 23 , 10 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## --------------- ----- ----------- ------- ---------- --------- ------- ---------- ---------
## 2-Phenylphenol 3 1/17/2016 SF 0.0000000 25.000 TF 0.0000000 10.000
## 2-Phenylphenol 3 10/8/2015 SF 0.0000000 20.000 TF 0.1900000 3.750
## 2-Phenylphenol 3 11/8/2015 SF 0.0000000 NA TF 0.3000000 2.000
## 2-Phenylphenol 3 12/17/2015 SF 0.1700000 25.000 TF 0.2100000 12.000
## 2-Phenylphenol 3 3/18/2015 SF 0.0000000 0.132 TF 0.3622047 0.635
## 2-Phenylphenol 3 4/16/2015 SF 0.1194030 0.670 TF 0.2200000 3.000
## 2-Phenylphenol 3 5/1/2015 SF 0.0000000 16.000 TF 0.2000000 1.000
## 2-Phenylphenol 3 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## 2-Phenylphenol 3 6/10/2015 SF 0.0000000 15.000 TF 0.0000000 4.000
## 2-Phenylphenol 3 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## 2-Phenylphenol 3 7/10/2015 SF 0.0400000 8.500 TF 0.0000000 3.000
## 2-Phenylphenol 3 7/17/2015 SF 0.0000000 NA TF 0.2800000 NA
## 2-Phenylphenol 3 7/2/2015 SF 0.0000000 NA TF 0.2000000 1.000
## 2-Phenylphenol 3 7/30/2015 SF 0.3700000 20.000 TF 0.2000000 4.000
## 2-Phenylphenol 3 8/13/2015 SF 0.0000000 13.000 TF 0.0000000 4.000
## 2-Phenylphenol 3 8/27/2015 SF 0.0500000 17.000 TF 0.0000000 4.000
## 2-Phenylphenol 3 9/17/2015 SF 0.6800000 2.500 TF 0.4700000 3.000
## 2-Phenylphenol 3 9/3/2015 SF 0.1818182 0.220 TF 0.2898551 0.690
## 2-Phenylphenol 4 1/17/2016 SF 0.0000000 25.000 TF 0.0000000 10.000
## 2-Phenylphenol 4 10/8/2015 SF 0.0000000 25.000 TF 0.1900000 4.000
## 2-Phenylphenol 4 11/8/2015 SF 0.0000000 15.000 TF 0.2100000 2.000
## 2-Phenylphenol 4 12/17/2015 SF 0.0000000 25.000 TF 0.0600000 12.000
## 2-Phenylphenol 4 3/18/2015 SF 0.0000000 1.000 TF 0.5454545 0.440
## 2-Phenylphenol 4 4/16/2015 SF 0.0000000 13.000 TF 0.0000000 2.000
## 2-Phenylphenol 4 5/1/2015 SF 0.0000000 5.000 TF 0.2000000 4.500
## 2-Phenylphenol 4 5/22/2015 SF 0.0000000 25.000 TF 0.0000000 6.000
## 2-Phenylphenol 4 6/10/2015 SF 0.0000000 25.000 TF 0.1900000 4.000
## 2-Phenylphenol 4 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## 2-Phenylphenol 4 7/10/2015 SF 0.0000000 25.000 TF 0.0000000 4.000
## 2-Phenylphenol 4 7/17/2015 SF 0.0000000 NA TF 0.1900000 NA
## 2-Phenylphenol 4 7/2/2015 SF 0.0740741 0.675 TF 0.0000000 4.000
## 2-Phenylphenol 4 7/30/2015 SF 0.0000000 25.000 TF 0.0000000 6.000
## 2-Phenylphenol 4 8/13/2015 SF 0.0000000 20.000 TF 0.0000000 6.000
## 2-Phenylphenol 4 8/27/2015 SF 0.0000000 25.000 TF 0.0000000 4.750
## 2-Phenylphenol 4 9/17/2015 SF 0.0100000 25.000 TF 0.1900000 3.000
## 2-Phenylphenol 4 9/3/2015 SF 0.0370370 0.540 TF 0.0000000 0.550
## 2-Phenylphenol 7 1/17/2016 SF 0.0000000 25.000 TF 0.0000000 7.000
## 2-Phenylphenol 7 10/8/2015 SF 0.0000000 17.000 TF 0.0000000 5.000
## 2-Phenylphenol 7 11/8/2015 SF 0.3700000 5.000 TF 0.0000000 1.000
## 2-Phenylphenol 7 12/17/2015 SF 0.0400000 25.000 TF 0.0000000 9.000
## 2-Phenylphenol 7 3/18/2015 SF 0.0000000 0.230 TF 0.2300000 0.550
## 2-Phenylphenol 7 4/16/2015 SF 0.0000000 12.500 TF 0.0000000 2.000
## 2-Phenylphenol 7 5/1/2015 SF 0.0000000 20.000 TF 0.0000000 5.000
## 2-Phenylphenol 7 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## 2-Phenylphenol 7 6/10/2015 SF 0.0800000 20.000 TF 0.0000000 5.000
## 2-Phenylphenol 7 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## 2-Phenylphenol 7 7/10/2015 SF 0.0000000 7.000 TF 0.0000000 2.000
## 2-Phenylphenol 7 7/17/2015 SF 0.0400000 NA TF 0.0000000 NA
## 2-Phenylphenol 7 7/2/2015 SF 0.0000000 3.000 TF 0.0000000 1.500
## 2-Phenylphenol 7 7/30/2015 SF 0.0000000 20.000 TF 0.1900000 3.500
## 2-Phenylphenol 7 8/13/2015 SF 0.0000000 15.000 TF 0.0000000 4.000
## 2-Phenylphenol 7 8/27/2015 SF 0.0000000 25.000 TF 0.0000000 4.000
## 2-Phenylphenol 7 9/17/2015 SF 0.0000000 14.000 TF 0.2300000 2.000
## 2-Phenylphenol 7 9/3/2015 SF 0.0154560 0.647 TF 0.4827586 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 100, p-value = 0.001911
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Flutolanil"
## [1] "Flutolanil stemflow detection frequency = 15 / 54"
## [1] "Flutolanil stemflow concentration range =( 0 , 0.38 )"
## [1] "Flutolanil throughfall detection frequency = 28 / 54"
## [1] "Flutolanil throughfall concentration range =( 0 , 0.63 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 23 , 26 , 5 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## ----------- ----- ----------- ------- ---------- --------- ------- ---------- ---------
## Flutolanil 3 1/17/2016 SF 0.0000000 25.000 TF 0.0000000 10.000
## Flutolanil 3 10/8/2015 SF 0.0000000 20.000 TF 0.1300000 3.750
## Flutolanil 3 11/8/2015 SF 0.0000000 NA TF 0.0000000 2.000
## Flutolanil 3 12/17/2015 SF 0.0000000 25.000 TF 0.0000000 12.000
## Flutolanil 3 3/18/2015 SF 0.0000000 0.132 TF 0.0000000 0.635
## Flutolanil 3 4/16/2015 SF 0.0000000 0.670 TF 0.0000000 3.000
## Flutolanil 3 5/1/2015 SF 0.0000000 16.000 TF 0.0000000 1.000
## Flutolanil 3 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Flutolanil 3 6/10/2015 SF 0.0000000 15.000 TF 0.0000000 4.000
## Flutolanil 3 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## Flutolanil 3 7/10/2015 SF 0.1500000 8.500 TF 0.6300000 3.000
## Flutolanil 3 7/17/2015 SF 0.2100000 NA TF 0.3500000 NA
## Flutolanil 3 7/2/2015 SF 0.0000000 NA TF 0.2000000 1.000
## Flutolanil 3 7/30/2015 SF 0.0000000 20.000 TF 0.1900000 4.000
## Flutolanil 3 8/13/2015 SF 0.0000000 13.000 TF 0.0000000 4.000
## Flutolanil 3 8/27/2015 SF 0.3800000 17.000 TF 0.2100000 4.000
## Flutolanil 3 9/17/2015 SF 0.0000000 2.500 TF 0.3300000 3.000
## Flutolanil 3 9/3/2015 SF 0.0000000 0.220 TF 0.0000000 0.690
## Flutolanil 4 1/17/2016 SF 0.0000000 25.000 TF 0.0000000 10.000
## Flutolanil 4 10/8/2015 SF 0.1800000 25.000 TF 0.1400000 4.000
## Flutolanil 4 11/8/2015 SF 0.0000000 15.000 TF 0.0800000 2.000
## Flutolanil 4 12/17/2015 SF 0.2200000 25.000 TF 0.0000000 12.000
## Flutolanil 4 3/18/2015 SF 0.0000000 1.000 TF 0.0000000 0.440
## Flutolanil 4 4/16/2015 SF 0.0000000 13.000 TF 0.0000000 2.000
## Flutolanil 4 5/1/2015 SF 0.0000000 5.000 TF 0.0000000 4.500
## Flutolanil 4 5/22/2015 SF 0.0000000 25.000 TF 0.0000000 6.000
## Flutolanil 4 6/10/2015 SF 0.0000000 25.000 TF 0.0000000 4.000
## Flutolanil 4 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## Flutolanil 4 7/10/2015 SF 0.0000000 25.000 TF 0.1100000 4.000
## Flutolanil 4 7/17/2015 SF 0.2300000 NA TF 0.2400000 NA
## Flutolanil 4 7/2/2015 SF 0.0000000 0.675 TF 0.0000000 4.000
## Flutolanil 4 7/30/2015 SF 0.2100000 25.000 TF 0.0800000 6.000
## Flutolanil 4 8/13/2015 SF 0.0000000 20.000 TF 0.2100000 6.000
## Flutolanil 4 8/27/2015 SF 0.1300000 25.000 TF 0.1900000 4.750
## Flutolanil 4 9/17/2015 SF 0.3000000 25.000 TF 0.3500000 3.000
## Flutolanil 4 9/3/2015 SF 0.0000000 0.540 TF 0.1818182 0.550
## Flutolanil 7 1/17/2016 SF 0.0000000 25.000 TF 0.0700000 7.000
## Flutolanil 7 10/8/2015 SF 0.0900000 17.000 TF 0.1000000 5.000
## Flutolanil 7 11/8/2015 SF 0.0000000 5.000 TF 0.1700000 1.000
## Flutolanil 7 12/17/2015 SF 0.0000000 25.000 TF 0.0000000 9.000
## Flutolanil 7 3/18/2015 SF 0.0000000 0.230 TF 0.0000000 0.550
## Flutolanil 7 4/16/2015 SF 0.0000000 12.500 TF 0.0000000 2.000
## Flutolanil 7 5/1/2015 SF 0.0000000 20.000 TF 0.0000000 5.000
## Flutolanil 7 5/22/2015 SF 0.0000000 NA TF 0.0000000 NA
## Flutolanil 7 6/10/2015 SF 0.0900000 20.000 TF 0.0900000 5.000
## Flutolanil 7 6/23/2015 SF 0.0000000 NA TF 0.0000000 NA
## Flutolanil 7 7/10/2015 SF 0.1200000 7.000 TF 0.1300000 2.000
## Flutolanil 7 7/17/2015 SF 0.0000000 NA TF 0.3000000 NA
## Flutolanil 7 7/2/2015 SF 0.2400000 3.000 TF 0.1500000 1.500
## Flutolanil 7 7/30/2015 SF 0.0000000 20.000 TF 0.1800000 3.500
## Flutolanil 7 8/13/2015 SF 0.1400000 15.000 TF 0.3100000 4.000
## Flutolanil 7 8/27/2015 SF 0.0000000 25.000 TF 0.3300000 4.000
## Flutolanil 7 9/17/2015 SF 0.0000000 14.000 TF 0.2500000 2.000
## Flutolanil 7 9/3/2015 SF 0.0927357 0.647 TF 0.2758621 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 63, p-value = 0.000744
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Biphenyl"
## [1] "Biphenyl stemflow detection frequency = 13 / 54"
## [1] "Biphenyl stemflow concentration range =( 0 , 1.34 )"
## [1] "Biphenyl throughfall detection frequency = 44 / 54"
## [1] "Biphenyl throughfall concentration range =( 0 , 0.07 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 35 , 10 , 9 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## --------- ----- ----------- ------- ------- --------- ------- ---------- ---------
## Biphenyl 3 1/17/2016 SF 0.00 25.000 TF 0.0000000 10.000
## Biphenyl 3 10/8/2015 SF 0.00 20.000 TF 0.0300000 3.750
## Biphenyl 3 11/8/2015 SF 0.00 NA TF 0.0700000 2.000
## Biphenyl 3 12/17/2015 SF 1.16 25.000 TF 0.0300000 12.000
## Biphenyl 3 3/18/2015 SF 0.00 0.132 TF 0.0472441 0.635
## Biphenyl 3 4/16/2015 SF 0.00 0.670 TF 0.0600000 3.000
## Biphenyl 3 5/1/2015 SF 0.00 16.000 TF 0.0300000 1.000
## Biphenyl 3 5/22/2015 SF 0.00 NA TF 0.0000000 NA
## Biphenyl 3 6/10/2015 SF 0.10 15.000 TF 0.0300000 4.000
## Biphenyl 3 6/23/2015 SF 0.00 NA TF 0.0300000 NA
## Biphenyl 3 7/10/2015 SF 0.01 8.500 TF 0.0200000 3.000
## Biphenyl 3 7/17/2015 SF 0.00 NA TF 0.0200000 NA
## Biphenyl 3 7/2/2015 SF 0.00 NA TF 0.0200000 1.000
## Biphenyl 3 7/30/2015 SF 0.68 20.000 TF 0.0200000 4.000
## Biphenyl 3 8/13/2015 SF 0.01 13.000 TF 0.0200000 4.000
## Biphenyl 3 8/27/2015 SF 0.00 17.000 TF 0.0300000 4.000
## Biphenyl 3 9/17/2015 SF 0.49 2.500 TF 0.0300000 3.000
## Biphenyl 3 9/3/2015 SF 0.00 0.220 TF 0.0000000 0.690
## Biphenyl 4 1/17/2016 SF 0.00 25.000 TF 0.0000000 10.000
## Biphenyl 4 10/8/2015 SF 0.00 25.000 TF 0.0200000 4.000
## Biphenyl 4 11/8/2015 SF 1.12 15.000 TF 0.0500000 2.000
## Biphenyl 4 12/17/2015 SF 0.00 25.000 TF 0.0200000 12.000
## Biphenyl 4 3/18/2015 SF 0.00 1.000 TF 0.0681818 0.440
## Biphenyl 4 4/16/2015 SF 0.25 13.000 TF 0.0400000 2.000
## Biphenyl 4 5/1/2015 SF 0.00 5.000 TF 0.0300000 4.500
## Biphenyl 4 5/22/2015 SF 0.00 25.000 TF 0.0300000 6.000
## Biphenyl 4 6/10/2015 SF 0.00 25.000 TF 0.0200000 4.000
## Biphenyl 4 6/23/2015 SF 0.00 NA TF 0.0200000 NA
## Biphenyl 4 7/10/2015 SF 0.00 25.000 TF 0.0000000 4.000
## Biphenyl 4 7/17/2015 SF 0.00 NA TF 0.0000000 NA
## Biphenyl 4 7/2/2015 SF 0.00 0.675 TF 0.0200000 4.000
## Biphenyl 4 7/30/2015 SF 0.00 25.000 TF 0.0200000 6.000
## Biphenyl 4 8/13/2015 SF 0.00 20.000 TF 0.0200000 6.000
## Biphenyl 4 8/27/2015 SF 0.02 25.000 TF 0.0200000 4.750
## Biphenyl 4 9/17/2015 SF 0.02 25.000 TF 0.0300000 3.000
## Biphenyl 4 9/3/2015 SF 0.00 0.540 TF 0.0500000 0.550
## Biphenyl 7 1/17/2016 SF 0.00 25.000 TF 0.0200000 7.000
## Biphenyl 7 10/8/2015 SF 0.00 17.000 TF 0.0200000 5.000
## Biphenyl 7 11/8/2015 SF 1.34 5.000 TF 0.0000000 1.000
## Biphenyl 7 12/17/2015 SF 0.28 25.000 TF 0.0300000 9.000
## Biphenyl 7 3/18/2015 SF 0.00 0.230 TF 0.0300000 0.550
## Biphenyl 7 4/16/2015 SF 0.00 12.500 TF 0.0300000 2.000
## Biphenyl 7 5/1/2015 SF 0.00 20.000 TF 0.0200000 5.000
## Biphenyl 7 5/22/2015 SF 0.00 NA TF 0.0000000 NA
## Biphenyl 7 6/10/2015 SF 0.00 20.000 TF 0.0000000 5.000
## Biphenyl 7 6/23/2015 SF 0.00 NA TF 0.0200000 NA
## Biphenyl 7 7/10/2015 SF 0.00 7.000 TF 0.0200000 2.000
## Biphenyl 7 7/17/2015 SF 1.04 NA TF 0.0300000 NA
## Biphenyl 7 7/2/2015 SF 0.00 3.000 TF 0.0300000 1.500
## Biphenyl 7 7/30/2015 SF 0.00 20.000 TF 0.0000000 3.500
## Biphenyl 7 8/13/2015 SF 0.00 15.000 TF 0.0200000 4.000
## Biphenyl 7 8/27/2015 SF 0.00 25.000 TF 0.0200000 4.000
## Biphenyl 7 9/17/2015 SF 0.00 14.000 TF 0.0300000 2.000
## Biphenyl 7 9/3/2015 SF 0.00 0.647 TF 0.0459770 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 359.5, p-value = 0.05626
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Atrazine"
## [1] "Atrazine stemflow detection frequency = 10 / 54"
## [1] "Atrazine stemflow concentration range =( 0 , 3.65 )"
## [1] "Atrazine throughfall detection frequency = 17 / 54"
## [1] "Atrazine throughfall concentration range =( 0 , 7.09 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 12 , 35 , 7 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## --------- ----- ----------- ------- ------- --------- ------- ------- ---------
## Atrazine 3 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## Atrazine 3 10/8/2015 SF 0.00 20.000 TF 0.00 3.750
## Atrazine 3 11/8/2015 SF 0.00 NA TF 0.00 2.000
## Atrazine 3 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## Atrazine 3 3/18/2015 SF 0.00 0.132 TF 0.00 0.635
## Atrazine 3 4/16/2015 SF 0.00 0.670 TF 0.00 3.000
## Atrazine 3 5/1/2015 SF 2.70 16.000 TF 7.09 1.000
## Atrazine 3 5/22/2015 SF 0.00 NA TF 0.00 NA
## Atrazine 3 6/10/2015 SF 2.69 15.000 TF 2.11 4.000
## Atrazine 3 6/23/2015 SF 1.01 NA TF 0.70 NA
## Atrazine 3 7/10/2015 SF 0.87 8.500 TF 0.00 3.000
## Atrazine 3 7/17/2015 SF 0.70 NA TF 0.24 NA
## Atrazine 3 7/2/2015 SF 0.00 NA TF 0.25 1.000
## Atrazine 3 7/30/2015 SF 0.00 20.000 TF 0.00 4.000
## Atrazine 3 8/13/2015 SF 0.42 13.000 TF 0.00 4.000
## Atrazine 3 8/27/2015 SF 0.00 17.000 TF 0.19 4.000
## Atrazine 3 9/17/2015 SF 0.00 2.500 TF 0.00 3.000
## Atrazine 3 9/3/2015 SF 0.00 0.220 TF 0.00 0.690
## Atrazine 4 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## Atrazine 4 10/8/2015 SF 0.00 25.000 TF 0.00 4.000
## Atrazine 4 11/8/2015 SF 0.00 15.000 TF 0.00 2.000
## Atrazine 4 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## Atrazine 4 3/18/2015 SF 0.00 1.000 TF 0.00 0.440
## Atrazine 4 4/16/2015 SF 0.00 13.000 TF 0.00 2.000
## Atrazine 4 5/1/2015 SF 2.44 5.000 TF 2.74 4.500
## Atrazine 4 5/22/2015 SF 3.65 25.000 TF 1.17 6.000
## Atrazine 4 6/10/2015 SF 0.66 25.000 TF 0.52 4.000
## Atrazine 4 6/23/2015 SF 0.00 NA TF 0.17 NA
## Atrazine 4 7/10/2015 SF 0.00 25.000 TF 0.00 4.000
## Atrazine 4 7/17/2015 SF 0.00 NA TF 0.00 NA
## Atrazine 4 7/2/2015 SF 0.00 0.675 TF 0.16 4.000
## Atrazine 4 7/30/2015 SF 0.00 25.000 TF 0.00 6.000
## Atrazine 4 8/13/2015 SF 0.00 20.000 TF 0.00 6.000
## Atrazine 4 8/27/2015 SF 0.00 25.000 TF 0.00 4.750
## Atrazine 4 9/17/2015 SF 0.00 25.000 TF 0.00 3.000
## Atrazine 4 9/3/2015 SF 0.00 0.540 TF 0.00 0.550
## Atrazine 7 1/17/2016 SF 0.00 25.000 TF 0.00 7.000
## Atrazine 7 10/8/2015 SF 0.00 17.000 TF 0.00 5.000
## Atrazine 7 11/8/2015 SF 0.00 5.000 TF 0.00 1.000
## Atrazine 7 12/17/2015 SF 0.00 25.000 TF 0.00 9.000
## Atrazine 7 3/18/2015 SF 0.00 0.230 TF 0.00 0.550
## Atrazine 7 4/16/2015 SF 0.00 12.500 TF 0.72 2.000
## Atrazine 7 5/1/2015 SF 0.68 20.000 TF 1.55 5.000
## Atrazine 7 5/22/2015 SF 0.00 NA TF 0.00 NA
## Atrazine 7 6/10/2015 SF 0.00 20.000 TF 0.37 5.000
## Atrazine 7 6/23/2015 SF 0.00 NA TF 0.30 NA
## Atrazine 7 7/10/2015 SF 0.00 7.000 TF 0.00 2.000
## Atrazine 7 7/17/2015 SF 0.00 NA TF 0.23 NA
## Atrazine 7 7/2/2015 SF 0.00 3.000 TF 0.00 1.500
## Atrazine 7 7/30/2015 SF 0.00 20.000 TF 0.00 3.500
## Atrazine 7 8/13/2015 SF 0.00 15.000 TF 0.00 4.000
## Atrazine 7 8/27/2015 SF 0.00 25.000 TF 0.52 4.000
## Atrazine 7 9/17/2015 SF 0.00 14.000 TF 0.00 2.000
## Atrazine 7 9/3/2015 SF 0.00 0.647 TF 0.00 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 81.5, p-value = 0.3004
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Metalaxyl"
## [1] "Metalaxyl stemflow detection frequency = 0 / 54"
## [1] "Metalaxyl stemflow concentration range =( 0 , 0 )"
## [1] "Metalaxyl throughfall detection frequency = 1 / 54"
## [1] "Metalaxyl throughfall concentration range =( 0 , 0.42 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 1 , 53 , 0 )"
## [1] "Metalaxyl does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Acetochlor"
## [1] "Acetochlor stemflow detection frequency = 5 / 54"
## [1] "Acetochlor stemflow concentration range =( 0 , 0.95 )"
## [1] "Acetochlor throughfall detection frequency = 18 / 54"
## [1] "Acetochlor throughfall concentration range =( 0 , 3.05 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 16 , 36 , 2 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## ----------- ----- ----------- ------- ------- --------- ------- ------- ---------
## Acetochlor 3 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## Acetochlor 3 10/8/2015 SF 0.00 20.000 TF 0.00 3.750
## Acetochlor 3 11/8/2015 SF 0.00 NA TF 0.00 2.000
## Acetochlor 3 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## Acetochlor 3 3/18/2015 SF 0.00 0.132 TF 0.00 0.635
## Acetochlor 3 4/16/2015 SF 0.00 0.670 TF 0.00 3.000
## Acetochlor 3 5/1/2015 SF 0.00 16.000 TF 0.00 1.000
## Acetochlor 3 5/22/2015 SF 0.00 NA TF 0.00 NA
## Acetochlor 3 6/10/2015 SF 0.00 15.000 TF 0.83 4.000
## Acetochlor 3 6/23/2015 SF 0.00 NA TF 1.34 NA
## Acetochlor 3 7/10/2015 SF 0.00 8.500 TF 0.00 3.000
## Acetochlor 3 7/17/2015 SF 0.00 NA TF 0.31 NA
## Acetochlor 3 7/2/2015 SF 0.00 NA TF 0.71 1.000
## Acetochlor 3 7/30/2015 SF 0.00 20.000 TF 0.38 4.000
## Acetochlor 3 8/13/2015 SF 0.00 13.000 TF 0.00 4.000
## Acetochlor 3 8/27/2015 SF 0.00 17.000 TF 0.00 4.000
## Acetochlor 3 9/17/2015 SF 0.00 2.500 TF 0.00 3.000
## Acetochlor 3 9/3/2015 SF 0.00 0.220 TF 0.00 0.690
## Acetochlor 4 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## Acetochlor 4 10/8/2015 SF 0.00 25.000 TF 0.00 4.000
## Acetochlor 4 11/8/2015 SF 0.00 15.000 TF 0.00 2.000
## Acetochlor 4 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## Acetochlor 4 3/18/2015 SF 0.00 1.000 TF 0.00 0.440
## Acetochlor 4 4/16/2015 SF 0.00 13.000 TF 0.00 2.000
## Acetochlor 4 5/1/2015 SF 0.00 5.000 TF 0.00 4.500
## Acetochlor 4 5/22/2015 SF 0.00 25.000 TF 0.00 6.000
## Acetochlor 4 6/10/2015 SF 0.33 25.000 TF 0.60 4.000
## Acetochlor 4 6/23/2015 SF 0.74 NA TF 0.69 NA
## Acetochlor 4 7/10/2015 SF 0.00 25.000 TF 0.17 4.000
## Acetochlor 4 7/17/2015 SF 0.95 NA TF 0.43 NA
## Acetochlor 4 7/2/2015 SF 0.00 0.675 TF 0.22 4.000
## Acetochlor 4 7/30/2015 SF 0.00 25.000 TF 0.25 6.000
## Acetochlor 4 8/13/2015 SF 0.00 20.000 TF 0.00 6.000
## Acetochlor 4 8/27/2015 SF 0.00 25.000 TF 0.00 4.750
## Acetochlor 4 9/17/2015 SF 0.00 25.000 TF 0.00 3.000
## Acetochlor 4 9/3/2015 SF 0.00 0.540 TF 0.00 0.550
## Acetochlor 7 1/17/2016 SF 0.00 25.000 TF 0.00 7.000
## Acetochlor 7 10/8/2015 SF 0.00 17.000 TF 0.00 5.000
## Acetochlor 7 11/8/2015 SF 0.00 5.000 TF 0.00 1.000
## Acetochlor 7 12/17/2015 SF 0.00 25.000 TF 0.00 9.000
## Acetochlor 7 3/18/2015 SF 0.00 0.230 TF 0.00 0.550
## Acetochlor 7 4/16/2015 SF 0.00 12.500 TF 0.00 2.000
## Acetochlor 7 5/1/2015 SF 0.00 20.000 TF 0.00 5.000
## Acetochlor 7 5/22/2015 SF 0.00 NA TF 0.00 NA
## Acetochlor 7 6/10/2015 SF 0.00 20.000 TF 0.71 5.000
## Acetochlor 7 6/23/2015 SF 0.19 NA TF 0.73 NA
## Acetochlor 7 7/10/2015 SF 0.30 7.000 TF 0.78 2.000
## Acetochlor 7 7/17/2015 SF 0.00 NA TF 0.75 NA
## Acetochlor 7 7/2/2015 SF 0.00 3.000 TF 3.05 1.500
## Acetochlor 7 7/30/2015 SF 0.00 20.000 TF 0.67 3.500
## Acetochlor 7 8/13/2015 SF 0.00 15.000 TF 0.43 4.000
## Acetochlor 7 8/27/2015 SF 0.00 25.000 TF 0.00 4.000
## Acetochlor 7 9/17/2015 SF 0.00 14.000 TF 0.00 2.000
## Acetochlor 7 9/3/2015 SF 0.00 0.647 TF 0.00 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 11, p-value = 0.000634
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Alachlor"
## [1] "Alachlor stemflow detection frequency = 0 / 54"
## [1] "Alachlor stemflow concentration range =( 0 , 0 )"
## [1] "Alachlor throughfall detection frequency = 0 / 54"
## [1] "Alachlor throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Alachlor does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Anthraquione"
## [1] "Anthraquione stemflow detection frequency = 4 / 54"
## [1] "Anthraquione stemflow concentration range =( 0 , 2.878787879 )"
## [1] "Anthraquione throughfall detection frequency = 5 / 54"
## [1] "Anthraquione throughfall concentration range =( 0 , 0.26 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 4 , 46 , 4 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## ------------- ----- ----------- ------- --------- --------- ------- ------- ---------
## Anthraquione 3 1/17/2016 SF 0.000000 25.000 TF 0.00 10.000
## Anthraquione 3 10/8/2015 SF 0.000000 20.000 TF 0.00 3.750
## Anthraquione 3 11/8/2015 SF 0.000000 NA TF 0.00 2.000
## Anthraquione 3 12/17/2015 SF 0.000000 25.000 TF 0.00 12.000
## Anthraquione 3 3/18/2015 SF 2.878788 0.132 TF 0.00 0.635
## Anthraquione 3 4/16/2015 SF 0.000000 0.670 TF 0.26 3.000
## Anthraquione 3 5/1/2015 SF 0.000000 16.000 TF 0.00 1.000
## Anthraquione 3 5/22/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 3 6/10/2015 SF 0.000000 15.000 TF 0.00 4.000
## Anthraquione 3 6/23/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 3 7/10/2015 SF 0.000000 8.500 TF 0.00 3.000
## Anthraquione 3 7/17/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 3 7/2/2015 SF 0.000000 NA TF 0.00 1.000
## Anthraquione 3 7/30/2015 SF 0.000000 20.000 TF 0.00 4.000
## Anthraquione 3 8/13/2015 SF 0.000000 13.000 TF 0.00 4.000
## Anthraquione 3 8/27/2015 SF 0.000000 17.000 TF 0.00 4.000
## Anthraquione 3 9/17/2015 SF 0.000000 2.500 TF 0.00 3.000
## Anthraquione 3 9/3/2015 SF 0.000000 0.220 TF 0.00 0.690
## Anthraquione 4 1/17/2016 SF 0.000000 25.000 TF 0.00 10.000
## Anthraquione 4 10/8/2015 SF 0.000000 25.000 TF 0.00 4.000
## Anthraquione 4 11/8/2015 SF 0.000000 15.000 TF 0.00 2.000
## Anthraquione 4 12/17/2015 SF 0.000000 25.000 TF 0.00 12.000
## Anthraquione 4 3/18/2015 SF 0.420000 1.000 TF 0.00 0.440
## Anthraquione 4 4/16/2015 SF 0.490000 13.000 TF 0.21 2.000
## Anthraquione 4 5/1/2015 SF 0.000000 5.000 TF 0.00 4.500
## Anthraquione 4 5/22/2015 SF 0.000000 25.000 TF 0.00 6.000
## Anthraquione 4 6/10/2015 SF 0.000000 25.000 TF 0.00 4.000
## Anthraquione 4 6/23/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 4 7/10/2015 SF 0.000000 25.000 TF 0.21 4.000
## Anthraquione 4 7/17/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 4 7/2/2015 SF 0.000000 0.675 TF 0.00 4.000
## Anthraquione 4 7/30/2015 SF 0.000000 25.000 TF 0.00 6.000
## Anthraquione 4 8/13/2015 SF 0.000000 20.000 TF 0.00 6.000
## Anthraquione 4 8/27/2015 SF 0.000000 25.000 TF 0.00 4.750
## Anthraquione 4 9/17/2015 SF 0.000000 25.000 TF 0.00 3.000
## Anthraquione 4 9/3/2015 SF 0.000000 0.540 TF 0.00 0.550
## Anthraquione 7 1/17/2016 SF 0.000000 25.000 TF 0.00 7.000
## Anthraquione 7 10/8/2015 SF 0.000000 17.000 TF 0.00 5.000
## Anthraquione 7 11/8/2015 SF 0.000000 5.000 TF 0.00 1.000
## Anthraquione 7 12/17/2015 SF 0.000000 25.000 TF 0.00 9.000
## Anthraquione 7 3/18/2015 SF 1.434783 0.230 TF 0.00 0.550
## Anthraquione 7 4/16/2015 SF 0.000000 12.500 TF 0.22 2.000
## Anthraquione 7 5/1/2015 SF 0.000000 20.000 TF 0.00 5.000
## Anthraquione 7 5/22/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 7 6/10/2015 SF 0.000000 20.000 TF 0.00 5.000
## Anthraquione 7 6/23/2015 SF 0.000000 NA TF 0.00 NA
## Anthraquione 7 7/10/2015 SF 0.000000 7.000 TF 0.00 2.000
## Anthraquione 7 7/17/2015 SF 0.000000 NA TF 0.21 NA
## Anthraquione 7 7/2/2015 SF 0.000000 3.000 TF 0.00 1.500
## Anthraquione 7 7/30/2015 SF 0.000000 20.000 TF 0.00 3.500
## Anthraquione 7 8/13/2015 SF 0.000000 15.000 TF 0.00 4.000
## Anthraquione 7 8/27/2015 SF 0.000000 25.000 TF 0.00 4.000
## Anthraquione 7 9/17/2015 SF 0.000000 14.000 TF 0.00 2.000
## Anthraquione 7 9/3/2015 SF 0.000000 0.647 TF 0.00 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 26, p-value = 0.8833
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Endosulfan Lactone"
## [1] "Endosulfan Lactone stemflow detection frequency = 0 / 54"
## [1] "Endosulfan Lactone stemflow concentration range =( 0 , 0 )"
## [1] "Endosulfan Lactone throughfall detection frequency = 1 / 54"
## [1] "Endosulfan Lactone throughfall concentration range =( 0 , 0.07 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 1 , 53 , 0 )"
## [1] "Endosulfan Lactone does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "DEA"
## [1] "DEA stemflow detection frequency = 11 / 54"
## [1] "DEA stemflow concentration range =( 0 , 9.54 )"
## [1] "DEA throughfall detection frequency = 3 / 54"
## [1] "DEA throughfall concentration range =( 0 , 1.55 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 2 , 43 , 9 )"
##
##
## Compound Site Date Type.x Conc.x Volume.x Type.y Conc.y Volume.y
## --------- ----- ----------- ------- ------- --------- ------- ------- ---------
## DEA 3 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## DEA 3 10/8/2015 SF 0.00 20.000 TF 0.00 3.750
## DEA 3 11/8/2015 SF 0.00 NA TF 0.00 2.000
## DEA 3 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## DEA 3 3/18/2015 SF 0.00 0.132 TF 0.00 0.635
## DEA 3 4/16/2015 SF 0.00 0.670 TF 0.00 3.000
## DEA 3 5/1/2015 SF 0.40 16.000 TF 1.55 1.000
## DEA 3 5/22/2015 SF 0.00 NA TF 0.00 NA
## DEA 3 6/10/2015 SF 0.50 15.000 TF 0.83 4.000
## DEA 3 6/23/2015 SF 0.71 NA TF 0.00 NA
## DEA 3 7/10/2015 SF 0.47 8.500 TF 0.00 3.000
## DEA 3 7/17/2015 SF 0.33 NA TF 0.00 NA
## DEA 3 7/2/2015 SF 0.00 NA TF 0.00 1.000
## DEA 3 7/30/2015 SF 0.08 20.000 TF 0.00 4.000
## DEA 3 8/13/2015 SF 0.08 13.000 TF 0.00 4.000
## DEA 3 8/27/2015 SF 0.02 17.000 TF 0.00 4.000
## DEA 3 9/17/2015 SF 0.00 2.500 TF 0.00 3.000
## DEA 3 9/3/2015 SF 0.00 0.220 TF 0.00 0.690
## DEA 4 1/17/2016 SF 0.00 25.000 TF 0.00 10.000
## DEA 4 10/8/2015 SF 0.00 25.000 TF 0.00 4.000
## DEA 4 11/8/2015 SF 0.00 15.000 TF 0.00 2.000
## DEA 4 12/17/2015 SF 0.00 25.000 TF 0.00 12.000
## DEA 4 3/18/2015 SF 0.00 1.000 TF 0.00 0.440
## DEA 4 4/16/2015 SF 0.00 13.000 TF 0.00 2.000
## DEA 4 5/1/2015 SF 9.54 5.000 TF 0.73 4.500
## DEA 4 5/22/2015 SF 0.72 25.000 TF 0.00 6.000
## DEA 4 6/10/2015 SF 0.11 25.000 TF 0.00 4.000
## DEA 4 6/23/2015 SF 0.00 NA TF 0.00 NA
## DEA 4 7/10/2015 SF 0.00 25.000 TF 0.00 4.000
## DEA 4 7/17/2015 SF 0.00 NA TF 0.00 NA
## DEA 4 7/2/2015 SF 0.00 0.675 TF 0.00 4.000
## DEA 4 7/30/2015 SF 0.00 25.000 TF 0.00 6.000
## DEA 4 8/13/2015 SF 0.00 20.000 TF 0.00 6.000
## DEA 4 8/27/2015 SF 0.00 25.000 TF 0.00 4.750
## DEA 4 9/17/2015 SF 0.00 25.000 TF 0.00 3.000
## DEA 4 9/3/2015 SF 0.00 0.540 TF 0.00 0.550
## DEA 7 1/17/2016 SF 0.00 25.000 TF 0.00 7.000
## DEA 7 10/8/2015 SF 0.00 17.000 TF 0.00 5.000
## DEA 7 11/8/2015 SF 0.00 5.000 TF 0.00 1.000
## DEA 7 12/17/2015 SF 0.00 25.000 TF 0.00 9.000
## DEA 7 3/18/2015 SF 0.00 0.230 TF 0.00 0.550
## DEA 7 4/16/2015 SF 0.00 12.500 TF 0.00 2.000
## DEA 7 5/1/2015 SF 0.00 20.000 TF 0.00 5.000
## DEA 7 5/22/2015 SF 0.00 NA TF 0.00 NA
## DEA 7 6/10/2015 SF 0.00 20.000 TF 0.00 5.000
## DEA 7 6/23/2015 SF 0.00 NA TF 0.00 NA
## DEA 7 7/10/2015 SF 0.00 7.000 TF 0.00 2.000
## DEA 7 7/17/2015 SF 0.00 NA TF 0.00 NA
## DEA 7 7/2/2015 SF 0.00 3.000 TF 0.00 1.500
## DEA 7 7/30/2015 SF 0.00 20.000 TF 0.00 3.500
## DEA 7 8/13/2015 SF 0.00 15.000 TF 0.00 4.000
## DEA 7 8/27/2015 SF 0.00 25.000 TF 0.00 4.000
## DEA 7 9/17/2015 SF 0.00 14.000 TF 0.00 2.000
## DEA 7 9/3/2015 SF 0.00 0.647 TF 0.00 0.435
##
## Wilcoxon signed rank test with continuity correction
##
## data: chem_merge$Conc.x and chem_merge$Conc.y
## V = 51, p-value = 0.9501
## alternative hypothesis: true location shift is less than 0
## [1] "======================================================="
## [1] "Endosulfan ether"
## [1] "Endosulfan ether stemflow detection frequency = 0 / 54"
## [1] "Endosulfan ether stemflow concentration range =( 0 , 0 )"
## [1] "Endosulfan ether throughfall detection frequency = 0 / 54"
## [1] "Endosulfan ether throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Endosulfan ether does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Cyprodinil"
## [1] "Cyprodinil stemflow detection frequency = 0 / 54"
## [1] "Cyprodinil stemflow concentration range =( 0 , 0 )"
## [1] "Cyprodinil throughfall detection frequency = 0 / 54"
## [1] "Cyprodinil throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Cyprodinil does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Triadimefon"
## [1] "Triadimefon stemflow detection frequency = 0 / 54"
## [1] "Triadimefon stemflow concentration range =( 0 , 0 )"
## [1] "Triadimefon throughfall detection frequency = 0 / 54"
## [1] "Triadimefon throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Triadimefon does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Chlorothalonil"
## [1] "Chlorothalonil stemflow detection frequency = 0 / 54"
## [1] "Chlorothalonil stemflow concentration range =( 0 , 0 )"
## [1] "Chlorothalonil throughfall detection frequency = 0 / 54"
## [1] "Chlorothalonil throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Chlorothalonil does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Diphenylamine"
## [1] "Diphenylamine stemflow detection frequency = 3 / 54"
## [1] "Diphenylamine stemflow concentration range =( 0 , 0.21 )"
## [1] "Diphenylamine throughfall detection frequency = 0 / 54"
## [1] "Diphenylamine throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 51 , 3 )"
## [1] "Diphenylamine does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Fipronil"
## [1] "Fipronil stemflow detection frequency = 0 / 54"
## [1] "Fipronil stemflow concentration range =( 0 , 0 )"
## [1] "Fipronil throughfall detection frequency = 0 / 54"
## [1] "Fipronil throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Fipronil does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Myclobutanil"
## [1] "Myclobutanil stemflow detection frequency = 0 / 54"
## [1] "Myclobutanil stemflow concentration range =( 0 , 0 )"
## [1] "Myclobutanil throughfall detection frequency = 0 / 54"
## [1] "Myclobutanil throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Myclobutanil does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Oxyfluorfen"
## [1] "Oxyfluorfen stemflow detection frequency = 0 / 54"
## [1] "Oxyfluorfen stemflow concentration range =( 0 , 0 )"
## [1] "Oxyfluorfen throughfall detection frequency = 0 / 54"
## [1] "Oxyfluorfen throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Oxyfluorfen does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Bifenthrin"
## [1] "Bifenthrin stemflow detection frequency = 1 / 54"
## [1] "Bifenthrin stemflow concentration range =( 0 , 0.08 )"
## [1] "Bifenthrin throughfall detection frequency = 0 / 54"
## [1] "Bifenthrin throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 53 , 1 )"
## [1] "Bifenthrin does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Fludioxonil"
## [1] "Fludioxonil stemflow detection frequency = 1 / 54"
## [1] "Fludioxonil stemflow concentration range =( 0 , 0.4 )"
## [1] "Fludioxonil throughfall detection frequency = 2 / 54"
## [1] "Fludioxonil throughfall concentration range =( 0 , 0.56 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 2 , 51 , 1 )"
## [1] "Fludioxonil does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Endosulfan sulfate"
## [1] "Endosulfan sulfate stemflow detection frequency = 0 / 54"
## [1] "Endosulfan sulfate stemflow concentration range =( 0 , 0 )"
## [1] "Endosulfan sulfate throughfall detection frequency = 0 / 54"
## [1] "Endosulfan sulfate throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Endosulfan sulfate does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Ethalfluralin"
## [1] "Ethalfluralin stemflow detection frequency = 0 / 54"
## [1] "Ethalfluralin stemflow concentration range =( 0 , 0 )"
## [1] "Ethalfluralin throughfall detection frequency = 0 / 54"
## [1] "Ethalfluralin throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Ethalfluralin does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Pendimethalin"
## [1] "Pendimethalin stemflow detection frequency = 0 / 54"
## [1] "Pendimethalin stemflow concentration range =( 0 , 0 )"
## [1] "Pendimethalin throughfall detection frequency = 0 / 54"
## [1] "Pendimethalin throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Pendimethalin does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Benfluralin"
## [1] "Benfluralin stemflow detection frequency = 0 / 54"
## [1] "Benfluralin stemflow concentration range =( 0 , 0 )"
## [1] "Benfluralin throughfall detection frequency = 0 / 54"
## [1] "Benfluralin throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Benfluralin does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Diazinon"
## [1] "Diazinon stemflow detection frequency = 0 / 54"
## [1] "Diazinon stemflow concentration range =( 0 , 0 )"
## [1] "Diazinon throughfall detection frequency = 0 / 54"
## [1] "Diazinon throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Diazinon does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Malathion"
## [1] "Malathion stemflow detection frequency = 0 / 54"
## [1] "Malathion stemflow concentration range =( 0 , 0 )"
## [1] "Malathion throughfall detection frequency = 0 / 54"
## [1] "Malathion throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Malathion does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Oxadiazon"
## [1] "Oxadiazon stemflow detection frequency = 0 / 54"
## [1] "Oxadiazon stemflow concentration range =( 0 , 0 )"
## [1] "Oxadiazon throughfall detection frequency = 1 / 54"
## [1] "Oxadiazon throughfall concentration range =( 0 , 0.04 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 1 , 53 , 0 )"
## [1] "Oxadiazon does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Piperonyl butoxide"
## [1] "Piperonyl butoxide stemflow detection frequency = 0 / 54"
## [1] "Piperonyl butoxide stemflow concentration range =( 0 , 0 )"
## [1] "Piperonyl butoxide throughfall detection frequency = 0 / 54"
## [1] "Piperonyl butoxide throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Piperonyl butoxide does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "Propyzamide"
## [1] "Propyzamide stemflow detection frequency = 0 / 54"
## [1] "Propyzamide stemflow concentration range =( 0 , 0 )"
## [1] "Propyzamide throughfall detection frequency = 0 / 54"
## [1] "Propyzamide throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "Propyzamide does not have enough detected values for wilcox test"
## [1] "======================================================="
## [1] "THPI (Tetrahydrophthalimide)"
## [1] "THPI (Tetrahydrophthalimide) stemflow detection frequency = 0 / 54"
## [1] "THPI (Tetrahydrophthalimide) stemflow concentration range =( 0 , 0 )"
## [1] "THPI (Tetrahydrophthalimide) throughfall detection frequency = 0 / 54"
## [1] "THPI (Tetrahydrophthalimide) throughfall concentration range =( 0 , 0 )"
## [1] "(throughfall_greater, ties, stemflow_greater) = ( 0 , 54 , 0 )"
## [1] "THPI (Tetrahydrophthalimide) does not have enough detected values for wilcox test"global analyses
Two values with high concentrations are not shown on the all tifton data figure.
print('=======================================================')## [1] "======================================================="print('global')## [1] "global"tifton_sf <- tifton[which(tifton$Type=='SF'),]
tifton_tf <- tifton[which(tifton$Type=='TF'),]
#merge on site, date, compound
tifton_merge <- merge(tifton_sf,tifton_tf,by=c("Compound","Site","Date"))
#change NAs to zeroes for conparisons and the Wilcox test
tifton_merge$Conc.x[is.na(tifton_merge$Conc.x)] <- 0
tifton_merge$Conc.y[is.na(tifton_merge$Conc.y)] <- 0
n_tf_greater <- sum(tifton_merge$Conc.y > tifton_merge$Conc.x)
n_ties <- sum(tifton_merge$Conc.y == tifton_merge$Conc.x)
n_sf_greater <- sum(tifton_merge$Conc.x > tifton_merge$Conc.y)
comparisons <- paste('(throughfall_greater, ties, stemflow_greater) = ('
,n_tf_greater,',',n_ties,',',n_sf_greater,')')
print(comparisons)## [1] "(throughfall_greater, ties, stemflow_greater) = ( 170 , 1466 , 92 )"tifton_wilcox <- wilcox.test(tifton_merge$Conc.x, tifton_merge$Conc.y,
alternative = 'less', paired = TRUE, exact = FALSE)
x_max <- max(tifton_merge$Conc.x)
y_max <- max(tifton_merge$Conc.y)
max_conc <- max(x_max,y_max)
max_conc_vector <- seq(0,max_conc,20)
print(tifton_wilcox)##
## Wilcoxon signed rank test with continuity correction
##
## data: tifton_merge$Conc.x and tifton_merge$Conc.y
## V = 13665, p-value = 0.001862
## alternative hypothesis: true location shift is less than 0plot(tifton_merge$Conc.x, tifton_merge$Conc.y,
xlim=c(0,4),ylim=c(0,4),
xlab='Stemflow Concentration',ylab='Throughfall Concentration',
main=paste('All Tifton Data (WRS p-value = ',round(tifton_wilcox$p.value,4),')'),
sub = comparisons)
abline(0,1,col='red')
permutation stat testing
For many of the chemicals, some/most observations have identical/not detected values, hence the warning message thrown by R: unique ranks cannot be computed for all observations in the Wilcox test. Since there are ties, this prevents the computation of an exact p-value. With high numbers of tied data, Wilcoxon tests are not trustworthy. Moreover, in most non-parametric tests we assume that the sampled populations are symmetric and have the same dispersion or shape, which is not verifiable here.
A permutation test may be more appropriate in this case, for example permTS (perm), pperm (exactRankTests), or the coin package. Although these approaches do not take advantage of the paired design.
results
Mixed bag at the moment. Overall inference on paired data shows that throughfall concentrations exceed stemflow concentration 170 times versus 92 of the opposite exceedance. This corresponds to a p-value of 0.0019 with the Wilcoxon Rank Sum test.
There will be complaints from reviewers about the unequal volumes of samples for the two media, we need to be clear that the collection time is the same for these paired comparisons.
I guess we can also break out how often the exceedances are a detect versus a non-detect as opposed to a detect versus detect comparison. Can we assume that the actual detection limit is lower for the higher volume stemflow samples? (meaning that the volumes may bias the analyses towards stemflow exceedances and not throughfall).
Stemflow concentrations probably plagued by dilution versus first flush issues. We may want to think about how to use sample volume or observed rainfall totals for these dates to look at this and separate small from large rain events.
Having detection limits will help us characterize the magnitude of the difference between stemflow and throughfall (for example, ratio calculations that are not possible by treating non-detects as zeroes).