Reduced Water Use in Barley and Maize Production Through Conservation Agriculture and Drip Irrigation

Simon Fonteyne,Nele Verhulst,Álvaro Flores García

doi:10.3389/fsufs.2021.734681

Abstract

The Mexican Bajío region is the country's main barley (Hordeum vulgare) producing area. Barley is commonly produced during the dry autumn–winter season using furrow irrigation with ground water, following which rainfed maize (Zea mays) is grown in the spring–summer season using supplementary irrigation. Ground water levels in the region are steadily dropping, and the introduction of water-saving technologies in agriculture is urgently required. Drip irrigation can reduce water use but is costly. Conservation agriculture—the combination of minimal tillage, permanent soil cover and crop diversification—might reduce water use, but studies in irrigated systems are scarce. We compared water use and grain yield in tillage-based conventional agriculture and conservation agriculture, both with furrow irrigation and drip irrigation, in a 3-year (six growing seasons) barley-maize field experiment. Additionally, side-by-side demonstrations of conventional and conservation agriculture were installed simultaneously in farmers' fields and yields, water use and fuel use were recorded. In the field experiment, yields did not differ significantly between production systems, but irrigation water use was on average 17% lower in conservation agriculture than in conventional agriculture, ~36% lower with drip irrigation compared with furrow irrigation in conventional tillage, and 40% lower with drip irrigation and conservation agriculture combined compared with conventional agriculture with furrow irrigation. Water use reductions differed strongly between years, depending on weather. The water saving through conservation agriculture in farmers' fields was similar to the water saving in the controlled experiment with about 17%. Additionally, in farmer's fields conservation agriculture reduced greenhouse gas emissions by 192 kg CO2 ha−1 and improved soil health. The implementation of conservation agriculture would be a cost-effective method to reduce water use in the barley-maize production system in the Mexican Bajío, while simultaneously reducing greenhouse gas emissions.

Highlights

Mexico is currently the largest exporter of beer and the second largest importer of barley (Hordeum vulgare L.) malt in the world (FAO, 20201)
When analyzed per irrigation type, there was no difference between conservation agriculture (CA) and conventional tillage (CT) with drip irrigation, but with furrow irrigation, CA yielded significantly more than CT
Under CA there was no difference in yields between the two types of irrigation, but under CT, drip irrigation yielded significantly better than furrow irrigation

Summary

Introduction

Mexico is currently the largest exporter of beer and the second largest importer of barley (Hordeum vulgare L.) malt in the world (FAO, 20201). Barley in Mexico is mainly produced in irrigated agriculture in the Bajío region, in Guanajuato and Queretaro states (SIAP, 2020). The region is increasingly suffering from water stress, which hampers agricultural production. The agricultural sector uses 84% of the state’s water to irrigate ∼3,36,000 ha of crops and is the largest water consumer in the state (Hoogesteger and Wester, 2017; SIAP, 2020). As a result of the intensive agriculture in the region, 19 of the 20 aquifers in the state are overexploited, and the groundwater level is dropping at a rate of up to 3 m year−1 (Wester et al, 2011; Romero et al, 2017; Flores et al, 2018). In order to assure the continued production of barley in the region, it is important to drastically reduce agricultural water consumption

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