Evaluation of saline water effects on use efficiency and soil nutrient availability of maize (Zea mays L.) under drip fertigation

A field experiment was conducted during the rabi season of 2022-23 at the Saline Water Scheme, Agricultural College Farm, Bapatla. The study’s objective was to evaluate the effects of saline water on nutrient use efficiency and soil nutrient availability in maize under drip fertigation. The experiment consisted of eight treatments and four replications, arranged in a randomized block design. Irrigation with the best available water along with the application of a recommended dose of fertilizer (240-80-80 NPK kg ha-1) recorded the highest uptake of N (88.2 and 62.4 kg ha-1), P (21.2 and 16.20 kg ha-1), and K (25.4 and 126.7 kg ha-1) in grain and stover of maize, respectively, which were at par with the alternate use of fresh water with saline water of 2 dS m-1. Nutrient use efficiencies, i.e., agronomic efficiency (7.4, 18.4, and 18.4 kg kg-1), physiological efficiency (85.2, 225.3, and 159.4 kg kg-1), apparent recovery efficiency (22.5, 17.0 and 48.7 %) and utilization efficiency (15.7, 39.1 and 39.1 kg kg-1) of N, P, and K, respectively, were also observed to be the highest under irrigation with the best available water along with a recommended dose of fertilizer application. Soil pH remained unaffected with saline water irrigation, whereas the EC of the soil was the highest under irrigation with saline water of 4 dS m-1 without the application of fertilizers. Soil-available nitrogen, phosphorous, and potassium were most elevated under irrigation with the best available water, with values of 152.5, 36.3, and 352.8 kg ha-1 respectively. The lowest values of nutrient uptake, nutrient use efficiencies, and soil available nutrients were recorded under irrigation with a water salinity of 4 dS m-1 without applying fertilizers. The use of a cyclical approach in utilizing both freshwater and saline water has demonstrated its effectiveness in mitigating the adverse effects of salts, resulting in enhanced efficiency in nutrient utilization and greater accessibility of soil nutrients.