Cost-Benefit Analysis for Single and Double Rice Cropping Systems under the Background of Global Warming

Qing Ye,Tianying Wang,Wanghua Huang,Yong Li,Wenjuan Xie,Yan Wang,Xiaoguang Yang

doi:10.3390/atmos11101048

Abstract

Global warming might expand crop growth areas for the prevailing single and double rice cropping systems in Southern China. Based on historical weather and crop data from 1981 to 2015, we evaluated the economic benefit and environmental cost for single and double rice cropping systems (SRCS and DRCS) in areas that are sensitive to climate variability in the middle and lower reaches of the Yangtze River. The five chosen indices were: net profit, agronomic nitrogen use efficiency (ANUE), water use efficiency (WUE), total amount, and global warming potential (GWP) of greenhouse gas (GHG). The goal of this study is to provide scientific evidence for local policymakers to use in selecting the most suitable rice cropping systems to maximize economic profits while adapting to climate change. The results showed that net profit was $171.4 per hectare higher for DRCS than for SRCS in the study region. In addition, output per unit nitrogen usage was $0.25 per kg N higher for DRCS than for SRCS. Net profit would increase if DRCS replaced SRCS, and the maximum amplitude of increase in net profit for this replacement occurred under the settings of 150 kg ha−1 nitrogen fertilizer level and continuous irrigation when the paddy water layer started to fade. On the other hand, annual variation in net profit for SRCS was consistently smaller than DRCS, regardless of changes in nitrogen fertilizer level and irrigation regime settings. SRCS showed better WUE than DRCS in both rainfed and irrigated situations, as well as lower seasonal CH4 and N2O emissions during the study period. Therefore, we conclude that SRCS is superior to DRCS for the sake of maximizing economic profit while maintaining sustainable agriculture in areas that are sensitive to climate variability in the middle and lower reaches of the Yangtze River.

Highlights

Under the background of global warming, increases in annual average temperatures ranged from 0.9 to 1.5 ◦ C in China from 1909 to 2011 [1]
water use efficiency (WUE) is defined as the output of grain yield per unit of water used by rice; IWUE is defined as the increase in grain yield per unit increase in applied irrigation water [42]
The results showed that the nitrogen fertilizer level of 150 kg ha−1 was the best for both single ricerice cropping systems (SRCS) and double rice cropping systems (DRCS) to achieve high agronomic nitrogen use efficiency (ANUE) and net profit at the same time (Figure 6)

Summary

Introduction

Under the background of global warming, increases in annual average temperatures ranged from 0.9 to 1.5 ◦ C in China from 1909 to 2011 [1]. In the middle and lower reaches of the Yangtze River, local warming led to a northward expansion of the northern limit for DRCS [10,11,12]. Compared with the period of 1961–1990, the northern. 2 2ofof expansion of the northern limit for DRCS [10,11,12]. Compared with the period of 1961–1990, the limit of DRCS shifted northward by 300 km from 2000 to 2010 [13]. This northward shift in the northern northern limit of DRCS shifted northward by 300 km from 2000 to 2010 [13]. This northward shift in limit of DRCS was projected to reach the Yellow River Basin in 2050 [14] and made it possible for the northern limit of DRCS was projected to reach the Yellow River Basin in 2050 [14] and made it DRCS to replace SRCS to achieve higher crop yields in the middle and lower reaches of the Yangtze possible for DRCS to replace SRCS to achieve higher crop yields in the middle and lower reaches of

Objectives

Methods

Discussion

Conclusion