Hydrogel-mediated effects on nutrient content and NPK uptake in barley (Hordeum vulgare L.) under varying fertiliser and irrigation regimes

A field experiment was carried out during the rabi seasons of 2023–24 and 2024–25 at the research farm, Mandawa, Jhunjhunu district, Rajasthan, to study the effect of irrigation levels and hydrogel application under different fertiliser doses on the nutrient uptake and protein content of barley (cv. RD-2035). The experiment was conducted in a split-plot design (SPD) with combinations of 9 treatments and 3 replications. The main plot consisted of 3 irrigation levels (1, 2 and 3 irrigations), while the subplots included 6 hydrogel nutrient treatments (100, 70 and 50 % nitrogen, phosphorous, potassium (NPK) with and without hydrogel at 2.5 kg ha-1). Hydrogel was applied in seed rows at sowing to enhance soil moisture retention. Significant variations were observed in nitrogen (N), phosphorus (P), potassium (K) and protein content and their uptake in barley as influenced by irrigation levels and hydrogel-based fertiliser management. The application of 3 irrigations (I3) resulted in the highest nutrient content and uptake in both grain and straw, while one irrigation treatment recorded the lowest values. Among moisture conservation practices, hydrogel at 2.5 kg ha-1 combined with 100 % NPK consistently produced the maximum NPK content and uptake, along with superior protein content during both years. These results demonstrate that integrated use of hydrogel and balanced fertilisation under optimal irrigation markedly enhances nutrient availability, uptake efficiency and overall crop quality, suggesting its potential as a sustainable moisture-conservation and nutrient-management strategy for improving barley productivity under variable climatic conditions.