A research trial was conducted at Agronomy Farm (SKUAST-K, Wadura, Jammu & Kashmir), during kharif 2017 and 2018 to evaluate nutrient removal in rice under various rice establishment methods and weed control measures. The study comprised of two factors: rice establishment techniques {Transplanting (TPR); Direct seeding (DSR) and System of rice intensification (SRI)} as main plot treatments and weed control measures {Butachlor @ 1500 g a.i ha⁻¹ (B); Penoxsulam @ 22.5 g a.i ha⁻¹ (P); Pyrazosulfuron ethyl + Pretilachlor @ 15 and 600 g a.i ha⁻¹ (PP); Bensulfuron methyl + Pretilachlor @ 60 and 600 g a.i ha⁻¹ (BP); 2 Conoweeding/Hand Weeding (CW/HW); Weed free (WF) and weedy check (WC)} as sub-plot treatments meant to evaluate the best establishment method and weed management practice for rice. Over DSR and transplanted rice, the SRI technique yielded a significant increase in dry biomass accumulation (17.04 and 17.20 t ha⁻¹) and grain (7.92 and 8.17 t ha⁻¹) and straw (9.60 and 10.17 t ha⁻¹) yields. Penoxsulam herbicide significantly showed higher grain and straw yield of 8.19 and 8.28 t ha⁻¹ and 10.13 and 10.44 t ha⁻¹, respectively, than other weed management measures by comparing the means using critical difference. TPR excelled in reducing dry weed biomass more than other established methods. All herbicides considerably reduced dry weed biomass, but Penoxsulam herbicide showed the greatest reduction in dry weed biomass and proved superior against complex weed flora. Weeds showed maximum contribution towards total Biomass under DSR, among rice establishment techniques. In contrast, among different weed control measures, it was maximum in weedy check treatment (Untreated Control) and minimum in penoxsulam treatment. SRI significantly excelled in crop (grain and straw) nutrient uptake compared to the DSR and TPR method, although different crop establishment techniques non-significantly influenced nutrient concentrations. Furthermore, penoxsulam treatment demonstrated higher crop (grain and straw) nutrient uptake among the various weed management measures. However, available soil nutrients were observed among establishment techniques, highest in DSR and lowest in SRI. Moreover, direct-seeded rice excelled SRI and transplanted rice in weed nutrient uptake, and among the different herbicidal treatments, penoxsulam recorded the lowest uptake in weeds. Nutrient budgeting demonstrated that DSR showed the maximum percentage of nutrient removal by weeds, and the minimum ratio was in TPR. In contrast, the lowest rate of nutrients removed via weeds were seen in penoxsulam application under various weed management measures.

The global scarcity of irrigation water poses a significant challenge to the sustainable production of rice and its availability worldwide. With a growing population driving increased demand for rice, it is crucial to enhance rice production while minimizing water usage. Achieving this requires a comprehensive understanding of the complex interactions between water and nitrogen dynamics and the formulation of strategies to optimize the application of irrigation water and nitrogen fertilizers. This study aims to investigate the impact of varying irrigation regimes and nitrogen application rates on rice growth attributes, yield performance, overall crop productivity, and economic returns. In the 2021 and 2022 rice growing season, two field experiments were carried out in split plot design with four nitrogen levels in sub plots [N0: Control, N1: 75% RDN (Recommended dose of nitrogen; @ 120 kg N ha⁻¹), N2: 100% RDN, and N3: 125% RDN] and four irrigation treatments in main plots [I1: recommended irrigation scheduling, I2: at field capacity (20 L m⁻²), I3: 10% depletion from field capacity (20 L m⁻²), and I4: 20% depletion from field capacity (20 L m⁻²). The experiments were replicated three times. The suggested irrigation scheduling treatment (flooded) showed improved growth characteristics, such as plant height, dry matter accumulation, leaf area index, tiller count, SPAD (Soil Plant Analysis Development) value, NDVI (Normalized Difference Vegetation Index) value, leaf relative water content, and yield attributes; however, these were comparable to the application of irrigation water at field capacity. Due to improved plant growth and yield-attributing characteristics, the I1 treatment recorded the highest grain yield of 8.58 t ha⁻¹ and 8.4 t ha⁻¹, although it was comparable to the I2 treatment, which had grain yields of 8.27 t ha⁻¹ and 8.15 t ha⁻¹ in 2021 and 2022. The grain yield reported by the N3 treatment were significantly greater than those of the N2 treatment, IN 2021 and 2022 respectively. Applying nitrogen at 125% RDN (Recommended dose of nitrogen) and irrigation water at field capacity produced the highest benefit–cost ratio (1.64), which was closely followed by the same irrigation regime and 100% RDN application (1.60 BC ratio). Comparable to irrigation at field capacity, the suggested irrigation schedule demonstrated enhanced growth features, yield attributes, productivity, and profitability. The best way to achieve the optimum growth, productivity, and profitability in transplanted rice was to provide irrigation water at field capacity and nitrogen @ 100% RDN.

Excessive nitrogenous fertilization in years resulted in larger nitrogen and profit losses. This problem can be reduced by using need-based and time-specific nitrogen management. Therefore, a field experiment was carried out during the Kharif season of 2019 and 2020 in order to evaluate the impact of precision nitrogen management on the phenology, yield and agrometeorological indices of hybrid maize genotypes at the Agronomy Research Farm, FoA Wadura, Sopore, SKUAST-Kashmir. The experiment was carried out in split-plot design consisting of maize hybrids (Shalimar Maize Hybrid-2 Vivek-45 and Kanchan-517) as main plot treatments and precision nitrogen management (T₁: Control, T₂: Recommended N, T₃: 25% N as basal ≤ LCC 3@20 kg N ha⁻¹, T₄: 25% N as basal ≤ LCC 3@30 kg N ha⁻¹, T₅: 25% N as basal ≤ LCC 4@20 kg N ha⁻¹, T₆: 25% N as basal ≤ LCC 4@30 kg N ha⁻¹, T₇: 25% N as basal ≤ LCC 5@20 kg N ha⁻¹ and T₈: 25% N as basal ≤ LCC 5@30 kg N ha⁻¹) as sub-plot treatments. Results demonstrated that maize hybrids showed a non-significant difference in attaining different phenophases during both years. However, Shalimar Maize Hybrid-2 demonstrated higher grain (62.35 and 60.65 q ha⁻¹) and biological yield (170.26 and 165.86 q ha⁻¹), a higher number of days to attain different phenological stages in comparison to Vivek-45 and Kanchan-517 thereby achieved higher heat units, PTUs, HTUs, PTI. The application of nitrogen through LCC ≤ 5@30 kg N ha⁻¹ noted higher grain yield (61.27 and 59.13 q ha⁻¹) and biological yield (171.30 and 166.13 q ha⁻¹) during 2019 and 2020 respectively. Higher values of Growing degree days (GDD), Heliothermal units (HTU), Photothermal units (PTU), Phenothermal index (PTI), heat use efficiency (HUE) and radiation use efficiency (RUE) were observed in the application of nitrogen through LCC ≤ 5@30 kg N ha⁻¹ and required the highest number of days to reach different phenophases than other treatments during crop growing seasons of 2019 and 2020. The results demonstrated that Nitrogen application based on LCC ≤ 5@30 proved effective and should be adopted in maize hybrids especially in Shalimar Maize Hybrid-2 to attain higher yield under the temperate climate of Kashmir Valley.

Increasing nitrogen use efficiency in rice intensification (SRI) is pivotal to achieving high crop yield and reducing nitrogen losses. To find the critical value of the leaf color chart (LCC) for real-time nitrogen (N) application in rice varieties under SRI, a field experiment was laid at the Research Farm, Faculty of Agriculture, Wadura, SKAUST-Kashmir in Kharif between 2019 and 2020. The experiment comprised two cultivars (SR-3 and SR-4) and eight LCC-based nitrogen managements (control, recommended dose of nitrogen (RDF), and three LCC scores (≤3, ≤4, ≤5 each with 20 and 30 kg N ha⁻¹). SR-4 produced significantly higher values for growth and yield parameters, producing higher grain yield (7.02 and 6.86 t ha⁻¹) compared to SR-3 (6.49 and 6.36 t ha⁻¹) between 2019 and 2020, respectively. An LCC value of 5 with 30 kg N ha⁻¹ produced maximum grain yield (7.84 and 7.70 t ha⁻¹) in 2019 and 2020, respectively, which were statistically at par with the LCC value of 5 with 20 kg Nha⁻¹. Pooled data revealed that the highest B: C ratio of 1.55 was recorded in cultivar SR-4 with an LCC value of 5 with 30 kg N ha⁻¹. Furthermore, agronomic and recovery efficiency of nitrogen remained maximum in LCC 5 with 20 kg N ha⁻¹ for both years. Grain yield recorded in LCC 3 20 kg N ha⁻¹ was similar to recommended nitrogen. The present study highlighted the need-based N application through LCC and proved effective in increasing the N-use efficiency and yield in rice.

Field experiment was conducted at Faculty of Agriculture, SKUAST-Kashmir, Wadura, Jammu and Kashmir during kharif seasons of 2019 and 2020 to assess the effect of precision nitrogen management through LCC on nutrient content and uptake of maize (Zea mays L.) under temperate conditions of Kashmir. The experiment comprised of three maize hybrids (SMH-2, Vivek-45 and Kanchan-517) assigned to main plots and seven Precision N management viz. nitrogen splits @ 20 and 30 kg N ha-1 managed through LCC (LCC scores of 3, 4 and 5), recommended nitrogen level and control in subplots. The treatments were replicated thrice in a split plot design. The results revealed that LCC ≤ 5 @ 30 kg N ha-1 recorded highest dry matter accumulation and periodic N uptake at all the stages of growth and highest P and K uptake by grain and straw at harvest. Further, highest dry matter accumulation and uptake of NPK was recorded in cultivar SMH-2 as compared to Vivek-45 and Kanchan-517 during 2019 and 2020 respectively. LCC based N application proved effective in increasing dry matter and nutrient content of maize hybrids.