EFFECT OF PHOSPHORUS LEVELS, BIOFERTILIZERS AND BIOCHAR ON ENZYME ACTIVITIES AND NUTRIENT CYCLING OF SOIL IN CHICKPEA (Cicer arietinum L.)

Abstract

The field experiment was conducted during rabi season of 2023-24 at Agronomy Research Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, Uttar Pradesh, to study the effect of phosphorous levels, biofertilizers and biochar on soil enzyme activities and nutrient cycling in chickpea (Cicer arietinum L.). The experiment was laid out in a randomized block design with ten treatments and three replications. Treatments consisted of 100% recommended dose of phosphorus (RDP), reduced levels (50 and 75% RDP), application of biochar @ 2.5 t ha-1, inoculation of seed with phosphate-solubilizing bacteria (PSB) and Rhizobium. The available nitrogen (N), phosphorus (P) and potassium (K) were determined after harvest, along with dehydrogenase activity (DHA), acid phosphatase, alkaline phosphatase and soil microbial biomass carbon (SMBC). The integrated treatment, T6 (75% RDP + biochar + PSB + Rhizobium) registered the highest available N (193.35 kg ha-1), P (15.89 kg ha-1) and K (264.88 kg ha-1), as compared to the control T1 (181.17, 11.67 and 247.62 kg ha-1 respectively). T6 recorded the maximum DHA (45.92 µg TPF g-1 soil h-1), acid phosphatase (15.81 µg PNP g-1 soil h-1), alkaline phosphatase (26.91 µg PNP g-1 soil h-1) and SMBC (235.32 mg C kg-1 soil), compared to the lowest values in T1. The integrated application of reduced dose of phosphorus with biochar and dual biofertilizers proved to be beneficial in terms of nutrient availability and microbial activity in soil. The treatment combination improved the microbial biomass and enzyme mediated transformations that enhance the nutrient cycling and fertility. Therefore, the application of 75% RDP along with biochar, PSB and Rhizobium proved to be a promising technique in improving the biological health of the soil and nutrient availability for chickpea crop.