Water use efficiency and evapotranspiration in maize-soybean relay strip intercrop systems as affected by planting geometries.

Tanzeelur Rahman,Shoaib Ahmed,Feng Yang,Junbo Du,Sajad Hussain,Xin Liu,Weiguo Liu,Guopeng Chen,Wenyu Yang,Lilian Chen,Guoping Zhang

doi:10.1371/journal.pone.0178332

Tanzeelur Rahman, Shoaib Ahmed + Show 9 more

Open Access

https://doi.org/10.1371/journal.pone.0178332

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Journal: PloS one	Publication Date: Jun 9, 2017
Citations: 39	License type: CC BY 4.0

Affiliation: Sichuan Agricultural University

Abstract

Optimum planting geometries have been shown to increase crop yields in maize-soybean intercrop systems. However, little is known about whether changes in planting geometry improve the seasonal water use of maize and soybean intercrops. We conducted two different field experiments in 2013 and 2014 to investigate the effects of changes in planting geometry on water use efficiency (WUE) and evapotranspiration (ETc) of maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] relay strip intercrop systems. Our results showed that the leaf area index of maize for both years where intercropping occurred was notably greater compared to sole maize, thus the soil water content (SWC), soil evaporation (E), and throughfall followed a decreasing trend in the following order: central row of maize strip (CRM) < adjacent row between maize and soybean strip (AR) < central row of soybean strip (CRS). When intercropped, the highest grain yield for maize and total yields were recorded for the 40:120 cm and 40:160 cm planting geometries using 160 cm and 200 cm bandwidth, respectively. By contrast, the highest grain yield of intercropped soybean was appeared for the 20:140 cm and 20:180 cm planting geometries. The largest land equivalent ratios were 1.62 for the 40:120 cm planting geometry and 1.79 for the 40:160 cm planting geometry, indicating that both intercropping strategies were advantageous. Changes in planting geometries did not show any significant effect on the ETc of the maize and soybean intercrops. WUEs in the different planting geometries of intercrop systems were lower compared to sole cropping. However, the highest group WUEs of 23.06 and 26.21 kg ha-1 mm-1 for the 40:120 cm and 40:160 cm planting geometries, respectively, were 39% and 23% higher than those for sole cropping. Moreover, the highest water equivalent ratio values of 1.66 and 1.76 also appeared for the 40:120 cm and 40:160 cm planting geometries. We therefore suggest that an optimum planting geometry of 40:160 cm and bandwidth of 200 cm could be a viable planting pattern management method for attaining high group WUE in maize-soybean intercrop systems.

Highlights

Scarce water resources is one of the crucial factors that contributes to the decline in agricultural productivity [1]
We found that an optimum planting geometry and bandwidth led to ameliorate the light environment of soybean canopy, and boost the productivity of maize-soybean intercrop systems [13]
Greater LAI was measured for intercropped maize in the different planting geometries compared to sole maize

Summary

Introduction

Scarce water resources is one of the crucial factors that contributes to the decline in agricultural productivity [1]. The current challenge in agriculture is to produce more yields by utilizing less water, especially in regions with limited land and water resources [2]. Maximizing crop water productivity by the most effective utilization of rain water resources is important in arid land agriculture [3]. How scarce water resources can be better absorbed by crops, is the core objective of arid land agriculture [4]. Intercropping can improve crop yield by more efficient utilization of resources such as nutrient, water, and solar radiation [5,6].

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