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ThesisItem Open Access REAL TIME NITROGEN APPLICATION IN WINTER RICE UNDER DIFFERENT CROP ESTABLISHMENT TECHNIQUES(AAU, Jorhat, 2020-10) Konwar, Milon Jyoti; Saikia, M.A field experiment entitled “Real time nitrogen application in winter rice under different crop establishment techniques” was carried out in the year 2017 and 2018 in the Instructional-Cum-Research (ICR) farm, Assam Agricultural University, Jorhat to study the relative performance of winter rice varieties with LCC- based N application under different crop establishment techniques. The experiment was comprising of 45 treatment combinations with three varieties viz., V1: Ranjit, V2: Bahadur, V3: Gitesh; three crop establishment techniques viz., M1: Transplanting, M2: System of Rice Intensification, M3: Direct seeding by drum seeder and five nitrogen application techniques viz., N0 : Recommended dose of N (60 kg ha-1); N1 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 2;N2 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 3; N3 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 4; N4 : 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5, laid out in a split-plot (split-split) design with varieties in the main plots, crop establishment techniques in the sub-plots and nitrogen application techniques in the sub-sub plots and were replicated thrice.The soil of the experimental site was sandy loam, acidic in reaction, medium in organic carbon and available N, low in available P2O5 and K2O. Among the different growth and physiological parameters viz., plant height, tillers m-2, dry matter accumulation, CGR, RGR and NAR, the highest values recorded in the variety Ranjit followed by Bahadur and Gitesh. Similarly, in case of crop establishment techniques and nitrogen application techniques, SRI and 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 recorded the highest values in different growth and physiological parameters viz., plant height, tillers m-2, dry matter accumulation, CGR, RGR, NAR during 2017 and 2018, respectively. Root volume was also significantly affected by different varieties and was found to be the highest in Ranjit followed by Bahadur and Gitesh. Similarly, in case of crop establishment techniques, the root volume was recorded highest in SRI method followed by transplanting and direct seeding by drum seeder whereas the root volume was found to be highest in application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 as compared to recommended dose of nitrogenin different nitrogen application techniques. The results from the pooled data revealed that the variety Ranjit recorded significantly the highest yield attributing characters and grain as well as straw yields of 47.22 q ha-1 and 87.12 q ha-1 during 2017 and 2018. In case of methods of crop establishment, SRI recorded significantly higher grain and straw yields of 46.54 q ha-1 7 and 85.86 q ha-1 as compared to sowing by drum seeder. Application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 recorded significantly the highest grain as well as straw yields of 53.65 q ha-1 and 94.48 q ha-1, respectively as compared to other treatments. Pooled data of the treatment combinations showed that application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 with Ranjit establishing with SRI method registered significantly higher grain and straw yields over other treatment combinations. The highest grain and straw yields of rice from the pooled data was recorded with the application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 in Ranjit when SRI method of crop establishment was followed. The uptake of N, P, K and total uptake had been significantly affected by different varietal treatments. The highest uptake was found in case of Ranjit followed by Bahadur and Gitesh. In different crop establishment techniques N, P, K and total uptake was found to be the highest in case of SRI method followed by transplanting and direct seeding by drum seeder. Highest uptake was also found in application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 in comparison to other treatments.Results from the apparent nitrogen balance sheet indicated that the highest net gain in available N in soil was recorded in application of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 in Ranjit when SRI method was followed during 2017 and 2018, respectively,as compared to other treatment combinations. In case of economics, the higher net returns and B:C ratio (1.65 and 1.62) was recorded under treatment combinations of 30 kg N as basal + 15 kg ha-1 N when LCC ≤ 5 with Ranjit and drum seeder method of crop establishment in 2017 and 2018, respectively.ThesisItem Open Access INTEGRATED NUTRIENT MANAGEMENT IN RICE–BUCKWHEAT CROPPING SEQUENCE(AAU, Jorhat, 2020-06) Basumatary, Mahadev Uzir; Saud, R. K.A field experiment entitled “Integrated Nutrient Management in Rice - buckwheat cropping sequence” was conducted during kharif of 2016 and 2017 and rabi of 2016-17 and 2017-18 at Krishi Vigyan Kendra (KVK) farm of Kokrajhar district under Lower Brahmaputtra Valley Zone (LBVZ) of Assam. The treatment consisted of Integrated Nutrient Management (INM) viz., T1 (control), T2 (100% RDF), T3 (100% RDF + FYM @ 10 t ha-1), T4 (75% RDF + 25% N through FYM), T5 (75% RDF + 25% N through vermicompost), T6 (50% RDF + 50% N through FYM), T7 (50% RDF + 50% N through vermicompost) and T8 (FYM @ 1 t ha-1 + mixture of Azospirillium amazonens A-10 and Bacilllus megaterium P-5 @ 4 kg ha-1, + Rock phosphate@ 10 kg, MOP @ 40 kg ha-1) applied to kharif rice (as main-plot treatment in rabi season) in randomised block design and replicated three times. In succeeding rabi season, each main- plot treatment was splitted into three sub plot treatments with three levels of recommended dose of fertilizers viz., B1 (0% RDF i.e. control), B2 (50 % RDF) and B3 (100% RDF) to buckwheat resulting into twenty four treatment combinations and replicated three times in split plot design. The result revealed that the highest grain yield (54.13 and 52.71 q ha-1) and straw yield (64.23 and 64.18 q ha-1) of rice were recorded with the application of treatment T3 (100% RDF + FYM @10t ha-1) during kharif, 2016 and 2017, respectively. Most of the growth and yield attributes, nutrient content and their uptake by the crop, organic carbon and available NPK status of soil after harvest of the kharif rice were maximum under application of T3 (100% RDF + FYM @ 10 t ha-1) followed by treatment T5 (75% RDF + 25% N through vermicompost) during both the years of experimentation. The highest net return (Rs.36417 ha-1) and B: C ratio (1.99) were obtained with the treatment T3 (100% RDF + 10 t FYM ha-1) followed by T5 (75% RDF + 25% N through vermicompost) having net return of Rs.32534 ha-1 and B:C ratio of 1.92 to kharif rice. During rabi season, the residual effect of treatment T3 (100% RDF + FYM @10 t FYM ha-1) showed higher growth, yield attributes, seed and stover yields of buckwheat as well as nutrient content and their uptake by the crop during both the years of experimentation. The highest seed yield (12.76 and 13.65 q ha-1) and stover yield (23.52 and 25.47 q ha-1) were recorded with the residual effect of the treatment T3 7 (100% RDF + FYM @10 t FYM ha-1) in rabi 2016-17 and 2017-18, respectively. Lower bulk density and higher organic carbon value and improvement in status of available NPK in soil after harvest of buckwheat (end of the rice – buckwheat sequence) were also recorded with the residual effect of T3 (100% RDF + FYM @ 10 t ha-1) applied to the preceding kharif rice. In terms of monetary return, the highest net return (Rs. 19070 ha-1) and B: C ratio (2.26) were recorded with the residual effect of T3 (100% RDF + FYM @ 10 t ha-1) followed by T5 (75% RDF + 25% N through vermicompost) with net return (Rs. 15630 ha-1) with B: C ratio (2.03) to buckwheat on the basis of average of two year (2016-17 and 2017-18) data. The result further revealed that the treatment B3 (100% RDF) resulted in higher values of growth, yield attributes, seed and stover yields, harvest index of rabi buckwheat as well as nutrient content and its uptake by crop, organic carbon and available NPK status with lower bulk density of soil after harvest of crop among the different levels of RDF (NPK) directly applied to buckwheat crop during both the years of investigation. Among RDF levels to buckwheat, maximum net return (Rs.14894 ha-1) with B: C ratio (1.89) was obtained with B3 (100% RDF). The treatment combination of T3B3 i.e. 100% RDF + FYM @10 t ha-1 with 100% RDF calculated highest net return (Rs.26674 ha-1) and B:C ratio (2.60) followed by treatment combination of T5B3 (75% RDF + 25% N through vermicompost with 100% RDF) with net returns of Rs. 19758 per hectare with B:C ratio of 2.18. The performance of rice-buckwheat cropping sequence was assessed on the basis of rice equivalent yield, net monetary returns and B:C ratio. In respect of all the above assessment, the application of 100% RDF + FYM @ 10 t ha-1 to kharif rice and 100% RDF to buckwheat was the most beneficial combination compared to rest of the treatments. However, the interaction differences were not up to the significant extent.ThesisItem Open Access EVALUATION OF WEED MANAGEMENT PRACTICES UNDER ORGANIC PRODUCTION IN RICE (A) – RICE (W) – TORIA CROPPING SEQUENCE(AAU, Jorhat, 2020-08) Hazarika, Jyoti Rekha; Baishya, A.An experiment entitled “Evaluation of weed management practices under organic production in autumn rice-winter rice-toria cropping sequence” was conducted for two consecutive years during 2018-19 and 2019-20 at Instructional-Cum-Research Farm of Assam Agricultural University, Jorhat. This study forms a part of the long-term experiment under All India Coordinated Research Project on Integrated Farming System with a view to evaluate the efficiency of cultural and mechanical weed management practices under organic production system. The experiment was laid out in Randomized Block Design replicating thrice with seven treatments viz., T1: two hand weeding (HW) in rice and 1 HW in toria, T2: one mechanical weeding (MW) + one HW in rice and one HW in toria, T3: intercropping (dhaincha in autumn and winter rice and french bean in toria, at 2:1 ratio in replacement series, T4: stale seedbed + reduced spacing (25%) + mulching with previous crop mulch + 1 HW ( in all the three crops), T5: locally available dry weed mulch (3 inch thick) + 1 hand pulling (in all the three crops), T6: incorporation of oilcake (5 t/ha) + 1 HW (in all the three crops) and T7: deep ploughing during summer + 1 HW (in all the three crops). Recommended doses of N were applied as 1/3 rd N through FYM + 1/3 rd N through vermicompost + 1/3 rd N through mustard oil cake to each crop of the sequence. The soil texture of the experimental site was sandy loam with acidic in soil reaction (pH 5.40). The initial soil status was medium in organic carbon (6.82 mg/kg) and available nitrogen (340.50 kg/ha), low in available phosphorus (8.80 kg/ha), available potash (95.23 kg/ha) and in soil available sulpher content (6.50 kg/ha). The results revealed that plant height and other yield attributing parameters as well as grain (30.90 q/ha in autumn rice and 33.51 q/ha in winter rice) and straw (42.37 q/ha in autumn rice and 43.17 q/ha in winter rice) yield of rice were recorded to be the highest in the treatment with stale seedbed + reduced spacing (25%) + mulching with previous crop mulch + 1 hand weeding (HW) i.e. treatment T4, while the lowest values were recorded under the treatment receiving 1 mechanical weeding + 1 hand weeding in rice and 1 HW in toria (T2). The yield attributing parameters as well as seed (5.92 q/ha) and stover yield (18.82 q/ha) of toria was the highest in T6 treatment. The highest REY of rice-rice-toria sequence was recorded in T4 (75.39 q/ha) and the lowest (66.03 q/ha) was under T2 treatment. The highest total weed density and dry weight of the sequence were found in T2 at 30 DAP/DAS (34.53 no./m2 and 14.56 7 g/m2), 60 DAP/DAS (35.40 no./m2 and 21.02 g/m2) and at harvest (48.69 no./m2 and 22.78 g/m2), whereas the lowest was observed in T4 treatment. The total N, P and K uptake by the crops were the highest in T4 treatment with values of 147.6, 49.9 and 154.6 Kg/ha respectively and the highest total N, P and K uptake while that by weeds were recorded in T2 treatment with 102.09, 19.93 and 170.21 Kg/ha in rice-rice-toria cropping sequence. Soil available N, P, K and S content as well as soil microbial parameters after completion of the sequence were recorded to be the highest in T3 treatment. In the present investigation, the gross return (`178974.00), net return (`27877.00) and B:C ratio (1.18) were found to be the highest under T4 treatment [stale seedbed + reduced spacing (25%) + mulching with previous crop mulch + 1 HW (in all the three crops)] and the lowest were recorded under T6 treatment [receiving mustard oilcake (@5 t/ha) + 1 HW (in all the three crops)]. Thus, considering the system productivity, and economic feasibility, the practice of stale seedbed + reduced spacing by 25% + mulching with previous crop mulch + 1 HW in all the three crops (T4) could be considered as the best organic weed management practice in case of rice- rice- toria cropping sequence under the prevailing climatic condition of Assam. However, this practice needs multi-locational trials in all the agro-climatic conditions to derive valid conclusion before putting forwarded for recommendation to the farmer’s. There is also need for further study on long term effect of these organic weed management practices on soil physical, chemical and biological properties.
