BUTTAR, TEJBIR SINGH, et al. “Spatial Variability of Soil Macronutrients at Farm-Scale in Irrigated Plains under Rice-Wheat Cropping System”. Journal of Soil and Water Conservation, vol. 24, no. 4, Feb. 2026, https://epubs.icar.org.in/index.php/JSWC/article/view/176479.