Pesticide use in the wheat-maize double cropping systems of the North China Plain: Assessment, field study, and implications

Abstract

In the North China Plain (NCP), rising inputs of pesticides have intensified the environmental impact of farming activities in recent decades by contributing to surface water and groundwater contamination. In response to this, the Chinese government imposed stricter regulations on pesticide approval and application, and better monitoring strategies are being developed. However, sufficient and well-directed research on the accumulation and impact of different pesticides is needed for informed decision-making. In this study, current pesticide use, and recent and current research on water contamination by pesticides in the NCP are reviewed and assessed. Additionally, a small-scale field study was performed to determine if residuals from currently-used pesticides in the NCP can be detected in surface water, and in connected shallow groundwater. The contaminants of interest were commonly used pesticides on winter wheat-summer maize fields (the dominant cropping system in the NCP), such as 2,4-D and atrazine. Sampling took place in May, July, and October 2013; and March 2014. Results from our literature research showed that sampling is biased towards surface water monitoring. Furthermore, most studies focus on organic chlorinated pesticides (OCPs) like the isomers of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH), which were banned in China in 1983. However, currently-used herbicides like 2,4-D and atrazine were detected in river water and groundwater in all samplings of our field study. The highest concentrations of 2,4-D and atrazine were found in the river water, ranging up to 3.00 and 0.96μg/L, respectively. The monitoring of banned compounds was found to be important because several studies indicate that they are still accumulating in the environment and/or are still illegally in use. However, supported by our own data, we find that the monitoring in groundwater and surface water of currently permitted pesticides in China needs equal attention, and should therefore be increased.

Determinants of intensity of uptake of alternative pest control methods: A case of small- scale tomato farmers in Kenya

“…Therefore, farmers engaging in non-farm activities divert labour and time away from crop management activities which lower the number of crop management practices adopted. This observation is in line with Brauns et al (2018)'s findings where participation in off-farm activities was positively associated with increased use of pesticides (decreased use of traditional hand weeding method) by farm households in China. Another possible explanation for the negative relationship could be due to a lower allocation of non-farm income to crop management activities as compared to non-agricultural activities which lead to a lower number of crop management practices being adopted.…”

Improving Zinc Concentration and Bioavailability of Wheat Grain through Combined Foliar Applications of Zinc and Pesticides

“…In China, foliar pesticide application is the second most commonly used practice after fertilizers in crop production (Brauns et al, 2018). According to the National Bureau of Statistics in 2017, the total amount of pesticides used in 2015 in China was 1.78 million tons, which makes China the largest consumer of pesticides in the world.…”

“…This issue is important because wheat is commonly attacked by other foliar diseases (e.g., head blight, powdery mildew, and leaf rust) and pests (e.g., midge and red spider mite) (Liu et al, 2015). Various kinds of insecticides and fungicides are therefore annually sprayed on wheat plants (Brauns et al, 2018). Moreover, the periods for the insecticide and fungicide spray were different, occurring typically at flowering or milk stages (Ram et al, 2016).…”

Agriculture Development, Pesticide Application and Its Impact on the Environment

“…There are many reports about pesticide contamination of both surface water and groundwater worldwide [179][180][181][182][183][184]. For example, the United States Geological Survey (USGS) found several pesticides in more than 90% of water and fish samples collected from US streams [185].…”