Large Scale Agricultural Plastic Mulch Detecting and Monitoring with Multi-Source Remote Sensing Data: A Case Study in Xinjiang, China

Yuankang Xiong,Anming Bao,Yujuan Wang,Qingling Zhang,Jieyun Zhang,Xi Chen

doi:10.3390/rs11182088

Abstract

Plastic mulching has been widely practiced in crop cultivation worldwide due to its potential to significantly increase crop production. However, it also has a great impact on the regional climate and ecological environment. More importantly, it often leads to unexpected soil pollution due to fine plastic residuals. Therefore, accurately and timely monitoring of the temporal and spatial distribution of plastic mulch practice in large areas is of great interest to assess its impacts. However, existing plastic-mulched farmland (PMF) detecting efforts are limited to either small areas with high-resolution images or coarse resolution images of large areas. In this study, we examined the potential of cloud computing and multi-temporal, multi-sensor satellite images for detecting PMF in large areas. We first built the plastic-mulched farmland mapping algorithm (PFMA) rules through analyzing its spectral, temporal, and auxiliary features in remote sensing imagery with the classification and regression tree (CART). We then applied the PFMA in the dry region of Xinjiang, China, where a water resource is very scarce and thus plastic mulch has been intensively used and its usage is expected to increase significantly in the near future. The experimental results demonstrated that the PFMA reached an overall accuracy of 92.2% with a producer’s accuracy of 97.6% and a user’s accuracy of 86.7%, and the F-score was 0.914 for the PMF class. We further monitored and analyzed the dynamics of plastic mulch practiced in Xinjiang by applying the PFMA to the years 2000, 2005, 2010, and 2015. The general pattern of plastic mulch usage dynamic in Xinjiang during the period from 2000 to 2015 was well captured by our multi-temporal analysis.

Highlights

In a broad sense, agriculture using plastic film for crop cultivation can be defined as plasticulture [1]
Since the plastic-mulched farmland (PMF) had some slight variations in different years, and the classification and regression tree (CART) was easy to interpret, so we could slightly adjust the threshold about PMFA to improve the accuracy of long-term PMF mapping
The use of plastic mulch in agriculture is expected to continue increasing in China, especially in arid areas such as Xinjiang where water resource is extremely scarce

Summary

Introduction

Agriculture using plastic film for crop cultivation can be defined as plasticulture [1]. Since plastic film was used in agriculture in 1948 [2], it has been widely utilized for cultivating crops, fruits, and vegetables. The use of plastic film in agricultural can alleviate the threat of cold, high temperature, wind, insects, drought, and increase crop yield [3]. The widespread use of plastic mulch has significantly increased crop yield, which is of great significance for food security [5,6,7]. (iii) Plastic mulch and its inner surface with dew can block the emission of longwave radiation, increasing the temperature of the soil. (iv) Plastic mulch can block gas, such as N2O, CO2, and CH4, the exchange between soil and atmosphere. Plastic mulch can influence the residual rate of soil organic materials in the soil, inevitably affecting soil microbial and soil ecosystems [11]

Methods

Results

Conclusion