Effects of Crop Canopy and Rainfall Intensities on Runoff in Alfisols of Eastern Dry Zone of Karnataka

Abstract

Dryland ecosystems are highly susceptible to water and wind erosion due to the lack of vegetation on the soil surface. Plant and residue cover act as a protective shield, slowing down runoff and allowing water to infiltrate. The right crop selection, considering rainfall intensity, market demand, and resources, is crucial for soil and water conservation in dryland agriculture. Crops with good biomass, canopy cover, and extensive root systems effectively protect against erosion and reduce nutrient loss. Intercropping enhances soil coverage and shields the soil from raindrop impact. To address these issues, a study aimed to identify suitable crops and cropping systems in the Eastern Dry Zone of Karnataka, focusing on the relationship between rainfall characteristics, crop canopy cover, and runoff during different growth stages. The experiment included five open field plots totaling 20,304 m²: T1 (Pomelo) - 3,226 m², T2 (Castor) - 5,255 m², T3 (Pigeon pea) - 5,585 m², T4 (Chickpea) - 5,998 m², and T5 (control, no crop) - 240 m². Among the treatments, Pomelo (T1) had the lowest runoff of 5.33%, with substantial canopy cover (11.66 m²/tree). Castor (T2) recorded 7.23% runoff with 0.37 m²/plant cover, Pigeon pea (T3) had 8.44% with 0.34 m²/plant, Chickpea (T4) had 11.94% with the least cover (0.01 m²/plant) and Control (T5) with no crop cover had a 17.43% of runoff. The statistical analysis of the parameter was subjected to one factor CRD analysis and the results are significant with respect to crop canopy cover and runoff. The results showed that higher canopy cover effectively intercepts rainwater, allowing for better infiltration and reduced runoff. From a soil health perspective, T1 (Pomelo) was the most effective at minimizing runoff and retaining moisture during dry spells.