Response of NPK Fertilization and Irrigation in Nutrient and Soil Moisture Distribution Under High-Density Apple Plantation in the NW Himalayan Region

Abstract

ABSTRACT Drip fertigation provides enormous opportunities for the effective utilization and distribution of water and nutrients in sustainable management of orchard. Under various drip irrigation and fertigation schedules, the analysis of NO3 −-N and NH4 +-N distribution within the soil has been found to be efficacious to enhance the crop growth. Over the 2-year period of study (2019 and 2020), the response of NPK fertilization and irrigation in nutrient and soil moisture distribution under high-density apple plantation in the NW Himalayan region was investigated. In the present study, under drip irrigation, the wetting front extended up to 45 cm horizontally from the emitter; however, the maximum increase in soil moisture content remained confined near the emitting point. The soil moisture content decreased consistently with the increasing horizontal distance from the emitter. Drip irrigation recorded a higher soil moisture content at the surface soil depth of 0–15 cm compared to conventional surface irrigation, where the sub-surface soil depths of 15–30 cm registered a higher moisture content. The distribution of NO3 −-N and NH4 +-N content under drip fertigation nearly followed the soil moisture distribution pattern. The NO3 −-N and NH4 +-N content was maximum below the emitter and decreased thereafter with the increasing lateral distance from the emitter as nutrient mobility in soil is primarily governed by water movement. The decreasing trend of NO3 −-N and NH4 +-N with the increasing lateral distances is in accordance with the water distribution pattern under drip irrigation. The nutrient mobility is proved to be well pronounced under the drip fertigation system, and nutrients carried along with the water movement get concentrated near the outer periphery of the wetting zone.