To achieve higher crop yields and maintain environmental conservation, it is imperative to adopt novel agricultural methods that improve both the quantity and quality of produce. The following study focused on investigating the effectiveness of integrated use of biogas slurry and inorganic nutrigation on spinach growth and nutrient uptake through drip irrigation. A field experiment was conducted using a split-plot design; spinach was cultivated with seven different treatments: biogas slurry nutrigation (BSN) (T₁), integrated inorganic + organic nutrigation: 40% Recommended dose of fertilizer (RDF) + BSN (T₂), 60% RDF + BSN (T₃), 80% RDF + BSN (T₄), 100% RDF (T₅), slurry broadcasting (SB) (T₆), and control (T₇). The results showed that spinach grown with (T₄) 80% RDF + BSN exhibited optimum plant height and leaf count compared to spinach under other treatments and was at par with T₅ 100% RDF for crop parameters. T₅ treated plants demonstrated the longest roots, followed by T₄ treated plants. The highest recorded yield of 5.72 tons ha⁻¹ was achieved in treatment T₅ with 100% RDF, followed closely by T₄ with 80% RDF + BSN at 5.52 tons ha⁻¹ and T₃ with 60% RDF + BSN at 5.36 tons ha⁻¹. These three treatments exhibited comparable yields, showcasing the effectiveness of incorporating biogas slurry nutrigation in conjunction with inorganic fertilizer for achieving high spinach yields. In terms of macronutrient content in spinach leaves, significant differences were found for nitrogen (N), phosphorus (P), and potassium (K) contents. Incorporating biogas slurry into the soil modified microbial enzyme activities, specifically dehydrogenase and phosphatase. Normally, alkaline phosphatase shows greater activity than acidic phosphatase, but the addition of biogas slurry equalized the enzymatic activity of both, establishing a harmonized enzymatic profile. Our results suggest that fertilizing spinach with integrated biogas slurry nutrigation (if properly filtered) + inorganic nutrigation through drip nutrigation is a viable strategy for improving the morphological parameters and productivity of spinach while also contributing to environmental preservation and a reduction in production costs.

A field experiment was conducted on okra (Abelmoschus esculentus L.) for assessing the sustainability of yield with optimum irrigation schedule based on soil moisture depletion. Four irrigation treatments: Irrigation at I₁:20%, I₂:30%, I₃:40% and I₄:50% of soil moisture depletion rate in main plots and three fertilizer treatments: Fertigation at F₁:100%, F₂:80% and F₃:60% of recommended NPK (100:25:40 kg/ha) in subplots were tested. Soil matric potential was recorded continuously using electronic tensiometers. The soil moisture characteristics curve was derived for various soil matric potential value sand the soil water content. The irrigation controller triggered solenoid valves for irrigation when soil moisture depletion reached a prespecified level in each treatment. Soil moisture depletion values were significantly predicted based on a regression model calibrated for each treatment over the crop growing period. The model gave minimum prediction error (PE) for I₁, followed by I₂, I₃ and I₄, respectively. Plant growth and yield parameters were significantly influenced by the soil moisture availability under each treatment. It is recommended that irrigation be scheduled at 20% soil moisture depletion rate together with 100% NPK fertilizer application for attaining sustainable yield of okra (12.3 t/ha), apart from maximum WUE (3.5 kg/m³) and plant growth parameters under semiarid inceptisols.