Effects of mulching methods on soil water dynamics and corn yield of rain-fed cropland in the semiarid area of China

Abstract

Aims A new drought-resistance farming technology of double ridges and furrows mulched with plastic film and furrow planting (PMF) is widely applied on rain-fed agriculture in the middle and eastern part of Gansu Province,China, to increase crop yield and water use efficiency. However, its impacts on seasonal and annual soil water dynamics are not well understood. Our objectives were to (a) investigate seasonal and annual changes in soil wa-ter content, corn yield and water use efficiency of different mulching methods and (b) evaluate the ecological impact of PMF on rain-fed cropland in semi-arid areas. Methods We studied three treatments: PMF, whole field surface sand mulching and flat planting (SM) and un-covered and flat planting (CK). Using oven-drying and neutron-probe methods, we observed soil water in the 0–200 cm layer from 2009 to 2010. Important findings PMF could improve soil water storage in the 0–200 cm layer significantly before corn jointing and improve corn development in the early growth period. With corn growth, there was a significant difference in water consumption among the three treatments in the sequence PMF SM CK. Conversely, the se-quence of change of soil water storage was CK SM PMF. Under the same precipitation, soil water restoration depth of PMF was deepest and CK was shallowest (in the 0–200 cm soil layer). The quantity and depth of soil water consumption increased with increases of corn planting years in PMF treatment, e.g., depth of water con-sumption deepened from 20–120 cm to 120–200 cm from 2009 to 2010. After two years of continuous cropping of corn, soil water content in the 40–120 cm layer was 9.0% in all three treatments, the soil water content of PMF treatment decreased to 7.9% (which is close to the wilting coefficient of 7.2%) and corn development de-pended on rainfall in the growing season.This indicates that continuous corn cropping with PMF would result in a dry soil layer in semiarid areas. Water consumption, corn yield and water use efficiency were highest in PMF treatment, but lowest in CK in both years. Therefore, PMF could improve corn yield significantly,but continuous cropping may result in significant reduction of soil water storage and was disadvantageous to sustainable development capacity of cropland.