Water budgeting in conservation agriculture-based sub-surface drip irrigation in tropical maize using HYDRUS-2D in South Asia

Kiranmoy Patra,S L Jat,Sanjeev Panwar,B Gerard,M D Parihar,L K Singh,H S Nayak,Biswajit Rana,C M Parihar,V K Singh,M L Jat,H S Sidhu

doi:10.1038/s41598-021-93866-6

Abstract

In water scarce regions of South Asia, diversification of rice with maize is being advocated towards sustainability of cereal-based cropping systems. Adoption of innovative agronomic management practices, i.e., conservation agriculture (CA) and sub-surface drip irrigation (SSDI) are considered as key strategies for much needed interventions to address the challenges of water scarcity under projected climate change. Benefits from CA and SSDI concerning water economy are well-established, however, information about their complementarity and water budgeting in cereal-based systems are lacking. A field study was conducted with process-based model (HYDRUS-2D) to understand water transport, root water uptake and components of soil water balance in maize grown in rotation with wheat after five years of continuous adoption of conservation agriculture. In this study, altogether eight treatments comprising of 6 CA+ treatments (CA coupled with SSDI); permanent beds using sub-surface drip (PB-SSD) with (WR) and without (WOR) crop residue at different N rates, 0, 120 and 150 kg N ha−1 were compared with CA (PB using furrow irrigation-FI with crop residue-120 kg N ha−1) and conventional tillage practices (CT) (CT using FI without crop residue-120 kg N ha−1). Results showed that the model could simulate the daily changes in profile soil water content with reasonable accuracy in all the treatments. Simulated soil water balance indicated higher cumulative root water uptake (CRWU), lower cumulative evaporation (CE) and higher soil water retention in CA+ (PB-SSD+ crop residue at 150 and 120 kg N ha−1) than CA and CT plots. Hydrus-2D model efficiency > 0, RMSE between 0.009–0.026 and R2 value between 0.80–0.92 at P < 0.01 indicates that the model is performing efficiently. The mean evaporation from CA+ treatments was 10 and 36% less than CA and CT treatments, respectively. On average, CRWU under CA+ treatments were 14–48% higher than FI treatments. The mean cumulative deep drainage in CA+ plots was 80–100 mm less than CA and CT plots. In CA+ based plots significantly higher biomass production and radiation use efficiency were observed with reduced water use than CA and CT. Therefore, the study justifies the water-saving nature of CA+, while maintaining higher productivity and meeting the transpiration demand of crops and halting unnecessary evaporation and deep drainage losses.

Highlights

In South Asia, rice–wheat (RW) system (13.5 million ha) is the principal determinant of food and livelihood security for billions of p eople[1,2]
Results of the current study showed that conservation agriculture (CA)+ treatments is more efficient in converting captured solar radiation into biomass thereby, recorded higher radiation use efficiency (RUE) (Table 3)
Our research investigation has provided the first science-based evidence on basic and in-depth scientific insights on soil water balance components for irrigation water saving, improving water productivity, radiation use efficiency and crop biomass yield under concurrent use of subsurface drip irrigation (SSDI) and conservation agriculture (CA) in maize grown in rotation with wheat

Summary

Introduction

In South Asia, rice–wheat (RW) system (13.5 million ha) is the principal determinant of food and livelihood security for billions of p eople[1,2]. Over-exploitation of the groundwater for rice production is the most likely cause and free electricity for irrigation favours the over withdrawal In this context, alternate resource use efficient and productive maize production system must. The adoption of surface drip irrigation in cereal-based systems has remained a cumbersome process all the time, as the laterals get anchored during field operations both in conventional and CA systems. Compared to surface drip irrigation, SSDI restricts the evaporation losses from the soil surface, facilitates the delivery of water and nutrients directly to the root zone that leads to efficient water use, reduces weed emergence and labor cost and allows seeding with CA-based no-tillage practices[17]. Parihar et al.[9] simulated soil water dynamics in maize crop and found that cumulative root water uptake (CRWU) was significantly higher in CA-based zero-till (ZT) plots compared to CT plots

Methods

Results

Discussion

Conclusion