Effect of straw mulch and seeding rate on the harvest index, yield and water use efficiency of winter wheat

Changlu Hu,Xueyun Yang,Mao Ding,Victor O Sadras,Shulan Zhang,Cheng Zheng

doi:10.1038/s41598-018-26615-x

Changlu Hu, Xueyun Yang + Show 4 more

Open Access

https://doi.org/10.1038/s41598-018-26615-x

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Abstract

Straw mulching has been used to improve water use efficiency (WUE, yield per unit evapotranspiration) in the Loess Plateau of China, but the seeding rate may need to be adjusted from conventional practice. We tested the three-way interaction between seeding rate, soil management (conventional tillage and straw mulching) and seasons. Wheat yield ranged from 2851 to 6981 kg ha−1 and WUE from 5.3 to 16.2 kg ha−1 mm−1. Generally, soil water storage was higher and soil temperature was lower under straw mulching than under conventional practice. Evapotranspiration was higher under straw mulching. Yield was significantly affected by the interaction between straw mulching and season. Conventional practice showed significantly higher mean harvest index (HI), yield, and WUE than straw mulching in favorable seasons. However, yield was significantly higher under mulching than under conventional tillage in very dry season. Seeding rate had no effect on yield, but low seeding rate increased HI compared to high seeding rate. It is concluded that low seeding rate would be suitable for straw mulching.

Highlights

In China Loess Plateau, dryland farming is practiced on about 12.8 million ha or 80% of its arable land[1] where precipitation has declined at a rate of 1–2 mm y−1 in the last five decades[2,3]
We hypothesized that soil water storage improved by straw mulching would stimulate tillering, early growth and water use, lower seeding rate under straw mulching could partially counteract the risk of lower grain yield and harvest index
Higher grain yield was mainly connected to higher kernel weight, which was partially related to precipitation distribution (10 mm more post-anthesis) and 5 days longer duration of grain filling in the fourth season than in the second season

Summary

Introduction

In China Loess Plateau, dryland farming is practiced on about 12.8 million ha or 80% of its arable land[1] where precipitation has declined at a rate of 1–2 mm y−1 in the last five decades[2,3]. Recent reviews have shown that the response of rainfed wheat yield to straw mulching in the Loess Plateau varies from −20 to 74%, and the response of water use efficiency (WUE, yield per unit evapotranspiration) varies from −9 to 96%9,13 compared with conventional practice, whereas harvest index is reduced under straw mulching[8,14,15,16]. If straw mulch reduces grain yield by enhancing early growth and water use, we can expect a three way interaction between soil management (mulch vs conventional), seeding rate and seasonal conditions. We hypothesized that soil water storage improved by straw mulching would stimulate tillering, early growth and water use, lower seeding rate under straw mulching could partially counteract the risk of lower grain yield and harvest index

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