IndexAbstractIntroductionMaterials and methodsChemical analysis of plant sampleSoil chemical analysisStatistical analysis and data interpretationResults and discussionGrain and straw yieldNutrient concentrationNutrient absorptionNutrients available in the soil after harvest of the cropSummaryAn experiment was conducted during Kharif 2015 at Agricultural Water Management Research Farm, Sher-e-Kashmir University of Agricultural Science and Technology, Jammu (J&K), India, to study the effect of crop scheduling irrigation on yield and nutrient uptake of different direct-seeded basmati rice varieties. The results revealed that controlling irrigation schedules resulted in significantly higher cereal (3,370 kg ha-1) and straw (6,030 kg ha-1) yields, on par with irrigation at 2-day intervals via irrigator at 150% PE compared to other treatments. . Var. Pusa-1509 recorded a significantly higher grain yield (3240 kg ha-1) which was on par with Pusa-1121 (2960 kg ha-1) and a non-significant effect of varieties on straw yield was observed . However, control irrigation programs recorded significantly higher uptake of nitrogen (61.09 kg ha-1), phosphorus (19.70 kg ha-1) and potassium (116.18 kg ha-1) and also Pusa-1509 recorded significantly higher uptake of nitrogen (51.87 kg ha-1), phosphorus (16.51 kg ha-1) and potassium (103.68 kg ha-1). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay IntroductionRice (Oryza sativa L.), the staple food of more than half of the world's population, is an important target for providing food security and livelihoods for millions of people. Global rice demand is projected to increase by 25% from 2001 to 2025 to keep pace with population growth (Maclean et al., 2002), and thus, meet the ever-increasing rice demand sustainably with decreasing of natural resources is a great challenge. The most common methods for growing rice are direct seeding (direct dry seeding and direct wet seeding) and transplanting. Direct seeded rice (DSR) technique is becoming popular nowadays due to its demanding low input nature. Currently, direct-seeded rice (DSR) is gaining momentum due to labor shortages during the peak transplanting season and short-term water availability. Direct seeding of rice refers to the process of stabilizing the crop from seeds sown in the field rather than transplanting seedlings from the nursery. Direct seeding avoids three key operations, namely backfilling (a process in which the soil is compacted to reduce water infiltration), transplanting and maintaining standing water. DSR under aerobic conditions is one of the alternatives to replace the traditional transplantation method. According to Lafitte et al. (2002), the concept of DSR includes the use of nutrient-responsive rice varieties well adapted to aerobic soils with a yield potential of 70–80% of high-input flooded rice. The development of short-lived, early-maturing cultivars and efficient nutrient management techniques, together with the increased adoption of integrated weed management methods, have encouraged many farmers to switch from transplanted to DSR crops. Rice varieties show wide variation in producing high-density grains that showed the greatest potential for grain fill and test weight. Keeping these facts in mind, the present investigation was undertaken asEffect of irrigation scheduling on yield and nutrient uptake of different direct-seeded basmati rice varieties. Materials and Methods An experiment was conducted during Kharif 2015, at Agricultural Water Management Research Farm, Sher-e-Kashmir University of Agricultural Science and Technology, Jammu (J&K), India (located at 32o40' latitude N and 74o58' E longitude with an altitude of 332 m above mean sea level). The soil had a sandy-loamy texture with a pH of 8.23, EC 0.18 (dS/m), organic carbon (0.36%), total N (231.17 kg ha-1), available phosphorus ( 13.21 kg ha-1) and available potassium (142.17 kg ha-1). The experiment was conducted in a strip design with three replicates consisting of five irrigation schedules viz. Control (normal transplant with recommended water management practice), Irrigation/saturation with suction at 0.3 bar at 15 cm depth* (* Suction measured by tensiometer installed at 15 cm depth), Irrigation/saturation with suction at 0.4 bar at 15 cm depth* (* Suction measured via Tensiometer installed at 15 cm depth), Irrigation at 2-day intervals via sprinkler at 125% PE (cumulative evaporation value in pan for 2 days) and Irrigation at 2 day intervals via sprinklers at 150% PE (cumulative pan evaporation value for 2 days) for 2 days) in vertical plots and three varieties viz. Basmati-370, Pusa-1121 and Pusa-1509 in horizontal plots. The crop was sown in the third week of June. The recommended dose of fertilizer based on the variety was applied. Rice from each net plot in each replicate was harvested and dried. The grains after threshing were weighed and recorded as grain yield per net plot. Furthermore, this net grain yield per plot was converted into grain yield per hectare. Chemical analysis of plant sample Plant samples were taken from each plot at harvest to estimate the concentration of N, P and K. The samples were oven dried, then finely ground with an electric grinder and analyzed for concentration of nitrogen, phosphorus and potassium. N, P and K uptake in cereal and straw samples was calculated by multiplying the percentage of nutrient content by the respective dry matter accumulation according to the formula below: Nutrient content (%) x dry matter accumulation (kg ha-1) Nutrient uptake ( kg ha-1) = 100 The nitrogen content of grain and straw was estimated by the modified micro-kjeldhal method as outlined by Jackson (1967) and expressed as a percentage. The phosphorus content of cereals and straw was determined by the Vanadomolybdo phosphoric acid method, and the absorbance of the solution was recorded at 430 nm using a spectrophotometer, while the potassium content in the plant sample (cereals and straw separately) was determined by the flame photometer method. Soil chemical analysis Representative soil samples from the experimental plot were taken from the upper 15 cm depth before sowing the crop. Similarly, topsoil samples from 0 to 15 cm depth were also collected from each experimental plot at the time of harvesting. The collected soil samples were air-dried in the shade, pulverized with a wooden hammer and passed through a 2 mm sieve and analyzed for nitrogen, phosphorus and potassium content. Available nitrogen was determined by the alkaline permanganate method as outlined by Subbiah and Asija (1956). Available phosphorus was determined by Olsen et al., 1954 and available potassium iswas determined by the ammonium acetate extractable K method using the flame photometer as outlined by Jackson (1973). Statistical Analysis and Data Interpretation Data recorded on various parameters of the experiment were subjected to analysis using Fisher's analysis of variance (ANOVA) method and interpreted as outlined by Gomez and Gomez (1984). The significance levels used in the 'F' and 't' tests were P=0.05. Critical difference values ​​were calculated where the F test was significant. Results and Discussion Grain and Straw Yield The results of the study showed that irrigation scheduling at various thresholds and varieties of basmati rice significantly affected the grain and straw yield, as presented in Table 1. The highest grain (3,370 kg ha-1) and straw yield (6,030 kg ha-1) were observed with Control irrigation scheduling (normal transplanting with recommended water management practice), which was found to be on par with the watering at 2-day intervals using a sprinkler at 150% PE. The decrease in cereal and straw yield in other treatments was due to the decrease in soil water content following differentiated irrigation programs and therefore showed increased sensitivity for biomass production, leaf area and crop production. There was a consistent downward trend in grain and straw yields as the irrigation threshold increased from 0.3 to 0.4 bar. The lower yield of direct-sown rice under conditions of greater water deficit was largely due to reduced panicle density, increased tiller mortality and reduced fertility which may be due to abnormal pollen development due to insufficient availability of assimilated under higher stress conditions, as reported by Sudhir-Yadav et al. (2011), Zubaer et al. (2007) and Venuprasad et al. (2007). Application of irrigation at 2-day intervals via sprinkler at 150% PE produced a yield comparable to that of transplanted rice. This was due to moisture availability close to field capacity at a depth of 0-20 cm after irrigation scheduling which resulted in increased nutrient availability in the soil solution. Compared to the var. Pusa-1509 recorded significantly higher grain yield (3240 kg ha-1) which was on par with Pusa-1121 (2960 kg ha-1). This could be due to greater vegetative growth and better light interception which led to a higher leaf area index and subsequently to a greater distribution of dry matter towards the economic part. Yield variability among rice varieties could also be attributed to genetic traits. Ramanjaneyulu et al. (2014) revealed that phenotypic expressions largely depended on genotypic ability. Nutrient concentrationBetween treatments, the contents of nitrogen, phosphorus and potassium in grain and straw, influenced by irrigation schedules and varieties, differed significantly (Table 2). The highest concentration of N, P and K was recorded with irrigation schedule control which was on par with irrigation at 2-day intervals via sprinkler at 150% PE. In terms of variety, a significantly higher concentration of N, P and K was observed with var. Pusa-1509 which was found on par with Pusa-1121. Nutrient uptake The irrigation scheduling control recorded significantly higher nitrogen, phosphorus and potassium uptake by directly sown rice (61.0, 19.7 and 116.1 kg ha-1, respectively) and that was on par with the Watering at 2 day intervals via.