Pathak, K.BHARADWAJ, KRISHNA2021-01-052021-01-052020-07https://krishikosh.egranth.ac.in/handle/1/5810159225A field experiment entitled “Irrigation scheduling in rapeseed using Can evaporimeter” was carried out at Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat during the rabi season of 2018-19 to determine the suitable depth and schedule of irrigation in rapeseed(toria) based on Can evaporimeter and to find out the water requirement of rapeseed by scheduling irrigation with Can evaporimeter. The experiment was laid out in factorial randomized block design and replicated thrice. The treatments consisted of 3 depths of irrigation viz., irrigation of 4 cm depth (I1), irrigation of 5 cm depth (I2) and irrigation of 6 cm depth (I3) and 3 irrigation schedules viz. irrigation at 4 cm evaporation from Can evaporimeter (D1), irrigation at 5 cm evaporation from Can evaporimeter(D2) and irrigation at 6 cm evaporation from Can evaporimeter(D3).The soil of the experimental site was sandy loam in texture, acidic in reaction (pH 5.2), medium in organic carbon (0.70%), low in alkaline KMnO4 extractable N (243.7kg/ha), medium in Brays I P2O5 (24.9kg/ha) and low in 1 N ammonium acetate extractable K2O (151.6kg/ha). The toria variety “TS-38” was sown on 15th October, 2018 and harvested on 16th January, 2019. The total amount of rainfall received during the crop growth period was 69.8 mm. Experimental findings revealed that irrigation of 6 cm depth (I3) recorded the highest values for all growth characters in terms of plant height, dry matter accumulation, Leaf Area Index (LAI), Specific Leaf Area (SLA) and Crop Growth Rate (CGR) and Relative Growth Rate (RGR). Similarly, the yield attributing characters viz., branches/plant, number of siliquae/plant, number of seeds/siliqua and nutrient (NPK) uptake of rapeseed was observed to be highest under irrigation of 6 cm depth (I3). However, 6 cm irrigation (I3) recorded lower Specific Leaf Weight (SLW). The highest seed and stover yield (1104 kg/ha and 2052 kg/ha, respectively) was found under irrigation of 6 cm depth (I3) which was statistically at par with irrigation of 5 cm depth (I2) [1042 kg/ha and1942 kg/ha, respectively]. On the other hand, the test weight and harvest index (HI) were found to be non-significant under different treatment combinations. Likewise, irrigation of 6 cm depth (I3) also recorded the highest oil yield (465.9 kg/ha), highest water use (205.6 mm), crop WUE (89.9 kg/ha cm) and nutrient (NPK) uptake. Scheduling of irrigation at 4 cm evaporation from Can evaporimeter (D1) resulted in better growth parameters of the crop viz., plant height, dry matter accumulation, LAI, SLA, CGR and RGR. On the other hand, irrigation at 6 cm evaporation from Can evaporimeter (D3) recorded better SLW. Irrigation at 4 cm evaporation from Can evaporimeter (D1) also recorded the highest yield attributing characters viz., number of branches/plant, number of siliquae/plant and number of seeds/siliqua. The highest seed and stover yield was found under irrigation at 4 cm evaporation from Can evaporimeter (D1) [1173 kg/ha and 2152 kg/ha, respectively]. Similarly, irrigation at 4 cm evaporation from Can evaporimeter (D1) also recorded the highest oil yield (484.9 kg/ha), highest water use (216.3 mm), crop WUE (97.3 kg/ha cm) and nutrient (NPK) uptake. The highest field WUE (57.2 kg/ha cm) was recorded under irrigation scheduling at 5 cm evaporation from Can evaporimeter (D2). Irrigation of 6 cm depth at 4 cm evaporation from Can evaporimeter (I3D1) recorded the highest dry matter accumulation, siliquae/plant, seed yield and stover yield. It was closely followed by 5 cm irrigation at 4 cm evaporation from Can evaporimeter (I2D1), 4 cm irrigation at 4 cm evaporation from Can evaporimeter (I1D1), 6 cm irrigation at 5 cm evaporation from Can evaporimeter (I3D2) and 5 cm irrigation at 5 cm evaporation from Can evaporimeter (I2D2). However, I1D1 required less irrigation than I2D1 and I3D1 and recorded higher crop WUE and field WUE. In terms of economics, the highest gross return ( 41510.00/ha), net return ( 14322.00) and benefit-cost ratio (1.53) were obtained by application of 6 cm irrigation at 4 cm evaporation from Can evaporimeter (I3D1) and closely followed by application of 5 cm irrigation at 4 cm evaporation from Can evaporimeter (I2D1) with gross return, net return and benefit – cost ratio of 41125.00/ha, 14237.00 /ha] and 1.52, respectively.EnglishThesis