Towards groundwater neutral cropping systems in the Alluvial Fans of the North China Plain

Abstract

a b s t r a c tGroundwater levels in the North China Plain (NCP), the bread basket of China, have dropped more than one meter per year over the last 40 years, putting at risk the long term productivity of this region. Groundwater decline is most severe in the Alluvial Fans where our study site is located. Avoiding a foreseeable systems collapse requires region-wide changes in crop systems management, underpinned by sound environmental policies. Here, we explore the potential of crop system adaptation to remedy the excessive water use and quantify the likely yield penalties associated with more sustainable water use practices. Using simulations with the APSIM cropping systems model we explore production opportunities in an area within the NCP with intensive cropping and no access to irrigation from rivers. We estimate the attainable production levels for wheat and maize if agriculture were made groundwater neutral, through changes in crop sequence, irrigation practices and water conservation technologies (e.g. mulching with plastic film). Total grain production would drop by 44% compared to current practice if agriculture were made groundwater neutral. Water conservation by plastic film could limit this reduction to 21-33% but possible environmental impacts of plastic film need attention. This analysis facilitates a much needed debate on alternative agronomic practices and incentives through a quantitative comparison of adaptation options. Our biophysical analysis needs to be complemented with socio-economic considerations and discussions with all stakeholders. Similar analyses in other parts of the NCP are possible but require more accurate modelling of landscape hydrology and (towards the coast) risk of salt water intrusion.

Agricultural Policy Environmental eXtender (APEX) Simulation of Spring Peanut Management in the North China Plain

“…The North China Plain (NCP), which is often referred to as the breadbasket of China, provides more than 72% of the nation's wheat and 33% of its maize production [5]. Such achievements have heavily depended on continuous overexploitation of groundwater for irrigation and excessive mineral nitrogen (N) fertilizer application to meet the water and N requirement of intensive wheat-maize cropping systems [6,7]. Adjustment and optimization of cropping systems could be an effective strategy to mitigate groundwater depletion and reduce N input to ensure sustainable food production [8][9][10][11].…”

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

“…This negative effect of the agricultural activities on potential drinking water is especially problematic in the provinces of the NCP because of its high population density and its relatively low amounts of available water resources (Varis and Vakkilainen, 2001). Therefore, further decline in water quantity and quality is an imminent challenge for the area (van Oort et al, 2016;Sun et al, 2012;Zheng et al, 2015).…”

Modeling Water and Nitrogen Balance of Different Cropping Systems in the North China Plain

“…However, considering the results of scenario analyses, it is recommended that winter wheat would be cultivated at <200 mm irrigation by reducing one irrigation event.Since the 1970s, the annual use of the two-harvest cropping system greatly increased the total grain output. However, it has also caused severe groundwater decline [7,8], because both crops generally have high water requirements to complete their life cycle [9,10]. Crop water requirement does not meet the balance between groundwater recharge through rain and evapotranspiration (ET) loss from plant and soil [11].…”