Conservation agriculture augments water uptake in wheat: Evidence from modelling

Abstract

Field water balance and root water uptake in wheat were simulated with Hydrus-2D after a 7-year transition to conservation agriculture. The zero-tilled system with a 40% anchored residue improved soil structure and porosity. Water retention was augmented for most of the growing period, especially in the subsurface (15-30 cm), which was essentially a compact layer (penetration resistance >2 500 kPa). The lower soil strength allowed the roots to extend further as compared to conventional tillage. The loss in drainage was reduced by 54-74% over the season using zero tillage with residue. Improved initial crop establishment led to a higher leaf area index and also to an enhanced interception of photosynthetically active radiation. Soil evaporation was also reduced, and root water uptake was 14-17% higher in zero tillage with residue. The grain yield was 17% higher in zero tillage with residue with a marginally higher crop water uptake efficiency. The adoption of conservation agriculture optimized water uptake in wheat by the improving physical condition of the soil and plant water availability. Hydrus-2D was used to successfully simulate the soil water balance and root water uptake in wheat under conservation agriculture. Conservation agriculture requires a redesign of irrigation scheduling, unlike in conventional practice. The simulation of water balance in the soil will aid in irrigation water management in the wheat crop in order to achieve a higher degree of efficiency under conservation agriculture.