Optimizing Irrigation Scheduling to Enhance Nutrient Uptake and Soil Microbial Activity in Linseed Cultivation (Linum usitatissimum L.)

Linseed crop cultivated under residual moisture and water scarcity conditions in rabi season. To improve the productivity of linseed irrigation water is applied at different stages of crop. So, to optimize the irrigation scheduling and enhance the nutrient uptake and soil microbial activity, this experiment was conducted at Main Agriculture Research Station, University of Agricultural Sciences, Raichur (which comes under North Eastern Dry zone of Karnataka) (India) during rabi 2023-24. The experiment was carried out with Randomized Complete Block Design (RCBD) with five treatments and four replications. The results revealed that, pre sowing irrigation fb three irrigations at vegetative stage (30-35 DAS), flowering stage (40-45 DAS) and capsule development stage (60-65 DAS) (T4) recorded significantly higher nutrient uptake by linseed crop (46.07, 19.87 and 39.83 NPK kg ha-1). The rainfed condition treatment (T5) recorded significantly lower nutrient uptake by the crop (19.35, 8.15 and 18.40 NPK kg ha-1). Among the different treatments, pre sowing irrigation fb three irrigations at vegetative stage (30-35 DAS), flowering stage (40-45 DAS) and capsule development stage (60-65 DAS) recorded significantly higher soil microbial population of bacteria (16.1 X 106 cfu g-1 of soil), fungi (13.8 X 104 cfu g-1 of soil) and actinomycetes (6.8 X 103 cfu g-1 of soil) as compared to other treatments. The soil enzymatic activity was significantly influenced by scheduling of irrigation at different growth stages in linseed. At harvest among the different treatments, pre sowing irrigation fb three irrigations at vegetative stage (30-35 DAS), flowering stage (40-45 DAS) and capsule development stage (60-65 DAS) recorded significantly higher dehydrogenase, urease and alkaline phosphatase activity (18.63 μg TPF g-1 soil day-1, 22.5 μg NH4-N g-1 soil hr-1 and 14.4 µg PNP g-1 soil hr-1, respectively).