Effects of the ridge mulched system on soil water and inorganic nitrogen distribution in the Loess Plateau of China

A - Papers appearing in refereed journals

Jiang, R., Li, X., Zhu, W., Wang, K., Guo, S., Misselbrook, T. H. and Hatano, R. 2018. Effects of the ridge mulched system on soil water and inorganic nitrogen distribution in the Loess Plateau of China. Agricultural Water Management. 203, pp. 277-288.

AuthorsJiang, R., Li, X., Zhu, W., Wang, K., Guo, S., Misselbrook, T. H. and Hatano, R.
Abstract

The semi-arid region of the Loess Plateau is typical of rain-fed agricultural production in Northwestern China. In this area, the ridge mulched system (RM) is a widely-used measure to increase crop yield. The purpose of this
study was to investigate the effect of RM on soil water and inorganic nitrogen (N) distribution, and grain yield of maize (Zea mays L.). The study was conducted over three consecutive years and consisted of four treatments(each replicated three times): i) RM with N application rate of 260 kg N ha−1 (RM-N260); ii) RM with
180 kg N ha−1 (RM-N180); iii) a traditional flat cultivation system without mulching (F) with 260 kg N ha−1 (FN260); iv) F with 180 kg N ha−1 (F-N180). Mean soil water content during the maize growing season was increased by RM in 2013 only. However, RM increased the soil water storage significantly at the 3-leaf (V3) and 6-leaf stage (V6), and decreased evapotranspiration (ET) during pre-silking stage in all years. Compared to F, RM significantly improved maize grain yield by 79–123% in 2013, 23–25% in 2014, and 11–12% in 2015. Following three years of maize cultivation, soil inorganic N content increased substantially (two- to three-fold) in the RM system and 60% of the total inorganic N was accumulated in the top soil layers (0–60 cm) under the mulched ridge. Relative changes were much smaller in F, and most of inorganic N was stored in 0–20 cm and 100–160 cm soil layers. Generally, RM resulted in higher soil water storage during the pre-silking stage, which was the main reason for the improved maize grain yield. The nitrate leaching risk was reduced in RM-N180 compared with F,but nitrate leaching from the furrows between ridges was observed in RM-N260. However, the large increase in soil inorganic N content in RM-N180 after three years’ cultivation indicates an oversupply of N and a potential
risk of N losses to the environment over the longer term. Our study indicates, therefore, that RM is a suitable system for maize cropping in the semi-arid region of the Loess Plateau, with benefits in water and N use efficiency,but recommendations for appropriate N application rates are required to ensure long term agricultural sustainability, accounting for grain yields and environmental impacts. The mechanisms for inorganic N accumulation under the RM system are not fully understood and warrant further investigation.

KeywordsSoil water; Inorganic N; Plastic film mulch; Ridge mulched system; Maize; Loess Plateau
Year of Publication2018
JournalAgricultural Water Management
Journal citation203, pp. 277-288
Digital Object Identifier (DOI)doi:10.1016/j.agwat.2018.03.027
Open accessPublished as ‘gold’ (paid) open access
FunderBBSRC Newton funding
Funder project or codeUK - China Virtual Joint Centre for Improved Nitrogen Agronomy (CINAG)
Publisher's version
Output statusPublished
Publication dates
Online22 Mar 2018
Publication process dates
Accepted16 Mar 2018
PublisherElsevier Science Bv
Copyright licenseCC BY
ISSN0378-3774
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