Influence of Diverse Growing Environments and Plant Densities on Phenological Development and Agrometeorological Indices of Groundnut (Arachis hypogaea L.) in the Hyper Arid Zone of Rajasthan, India

Groundnut (Arachis hypogaea L.) stands as a significant oilseed crop globally. The growth, development, and productivity of these plants are notably affected by the adverse impacts of global climate change. Therefore, the current study sought to examine how diverse growing environments and planting densities influence the phenological development of groundnut in the hyper-arid zone of Rajasthan, India. A field experiment spanning the kharif seasons of 2017, 2018, and 2019 was conducted at Krishi Vigyan Kendra, Swami Keshwanand Rajasthan Agricultural University, Bikaner, India. The experiment laid out in split-plot design with four replications. The treatments included three main plots for growing environments (sowing on May 15, May 30, and June 15) and three sub-plots for planting densities (1.67 lakh ha-1, 2.50 lakh ha-1 and 3.33 lakh ha-1).. The outcomes of the field experiment indicates that sowing groundnut on May 30 was statistically on par with sowing on June 15 and resulted in higher values of GDD, helio thermal units (HTU), PTI, heat use efficiency (HUE), photothermal use efficiency (PUE), and heliothermal use efficiency, as well as hygrothermal use efficiency (Hg TUE-I and II) at the initiation of flowers and peg formation stages. However, at later growth stages significantly higher values of GDD, HTU, HUE, PUE, HgTUE-I and II were observed with the May 15 sowing. These values gradually decreased with delayed sowing up to May 30 and June 15. Further, increasing the planting density from 1.67 lakh ha-1, 2.50 lakh ha-1 and 3.33 lakh ha-1 significantly enhanced the HTU, HUE, PUE, HgTUE-I and II at various phenological stages of groundnut. Therefore, these findings underscore the significance of precise timing and density control in maximizing groundnut yields under challenging environmental circumstances. By understanding and modifying these variables, farmers can mitigate the adverse effects of climate change and enhance groundnut productivity, especially in extremely arid areas like Rajasthan.