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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 PERFORMANCE OF DIRECT SEEDED SALI RICE UNDER TWO DIFFERENT CROP ESTABLISHMENT METHODS AND WEED MANAGEMENT PRACTICES(AAU, Jorhat, 2020-06) M, Vigneshwaran; Sarmah, M.K.A field experiment entitled “Performance of direct seeded sali rice under two different crop establishment methods and weed management practices” was carried out at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat during the sali season of 2018-19 with a view to study the growth and yield behaviour of direct seeded sali rice under two different crop establishment methods and to find out the appropriate weed management practices for direct seeded sali rice. The experiment was laid out in a factorial RBD with three replications. The treatments consisted of two methods of sowing i.e., dry seeding (M1) and wet seeding (M2) and seven different weed management practices viz., two hand weedings at 20 & 40 DAS (W1), preemergence herbicide application of pretilachlor @ 0.75 kg a.i./ha (W2), pre-emergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS (W3), pre-emergence herbicide application of pyrazosulfuron ethyl @ 20 g a.i./ha (W4), pre-emergence herbicide application of pyrazosulfuron ethyl @ 20 g a.i./ha + one hand weeding at 40 DAS (W5), weed free check (W6) and weedy check (W7). The experimental field was infested with different types of grasses viz., Panicum repens, Leersia hexandra and Eragrostis unioloides, sedges viz., Cyperus rotundus L., Fimbristylis littoralis, and broad leaved weeds viz., Ageratum conyzoides, Alternanthera philoxeroides., Ludwigia decurrens and Acmella ciliate. The method of sowing brought significant influences on weed density and weed dry weight in all the growth stages. The wet seeding proved statistically superior in regards to growth attributes i.e. number of tillers/m2 and plant height at all growth stages compared to dry seeding. Similarly, wet seeding recorded significantly highest yield attributes i.e. number of panicles/m2 (160.11), panicle length (26.32 cm), number of filled grains/panicle (118.83) of sali rice followed by dry seeding. The wet seeding also recorded significantly highest grain yield (31.27 q/ha) and straw yield (49.04 q/ha). Higher uptake of nitrogen, phosphorus and potassium in grain, straw and total uptake by sali rice and lower uptake by weeds were recorded in wet seeding. Among the different weed management practices, weed free plot recorded the lowest weed density and weed dry matter, highest weed control efficiency and highest weed control index at all growth stages as well as recorded the highest growth characters, yield attributes, grain yield and straw yield. Results indicated that apart from the weed free plot, pre-emergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS and pre-emergence herbicide application of pyrazosulfuron ethyl @ 20 g a.i./ha + one hand weeding at 40 DAS shown the lowest weed density, dry weight, highest WCI, highest WCE at 45, 60 DAS and at harvest stage as well as it recorded the highest yield attributes, grain yield and straw yield. At 30 and 60 DAS, lowest uptake of nutrients by weeds were recorded in weed free check followed by two hand weedings at 20 & 40 DAS. At harvest, lowest uptake by weeds were recorded in weed free check followed by pre-emergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS. Significantly higher uptake of nitrogen, phosphorus and potassium in grain, straw and total uptake by sali rice was recorded in weed free check followed by pre-emergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS and pre-emergence herbicide application of pyrazosulfuron ethyl @ 20 g a.i./ha + one hand weeding at 40 DAS. The treatment combination of wet seeding (M2) combined with the weed free check recorded the highest grain yield (41.33 q/ha) and straw yield (59.33 q/ha) and it was statistically at par with the treatment combination of wet seeding along with preemergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS. An economic analysis showed that treatment combination of wet seeding combined with pre-emergence herbicide application of pretilachlor @ 0.75 kg a.i./ha + one hand weeding at 40 DAS (M2W3) recorded the highest net return (Rs. 63,089/ha) and benefit cost ratio (1.76).ThesisItem Open Access NUTRIENT MANAGEMENT IN RAPESEED THROUGH ORGANIC SOURCES(AAU, Jorhat, 2020-09) Lhamu, Sonam; Das, J. C.An experiment on “Nutrient management in rapeseed through organic sources” was carried out in the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat to study the effect of different organic sources of nutrients on growth and yield of rapeseed during the rabi season of 2018-19. The treatments consisted of eleven levels of organic sources of nutrients viz., T1 – FYM @ 10 t/ha, T2 – Vermicompost @ 5 t/ha, T3 – Poultry Manure @ 5 t/ha, T4 – FYM @ 5 t/ha + vermicompost @ 2.5 t/ha, T5 – FYM @ 5 t/ha + poultry manure @ 2.5 t/ha, T6 – Vermicompost @ 2.5 t/ha + poultry manure @ 2.5 t/ha, T7 – FYM @ 5 t/ha + vermicompost @ 2.5 t/ha + mustard oil cake @ 1 t/ha, T8 – FYM @ 5 t/ha + poultry manure @ 2.5 t/ha + mustard oil cake @ 1 t/ha, T9 – Vermicompost @ 2.5 t/ha + poultry manure @ 2.5 t/ha + mustard oil cake @ 1 t/ha, T10 – FYM @ 5 t/ha + vermicompost @ 1.25 t/ha + poultry manure @ 1.25 t/ha + mustard oil cake @ 1 t/ha including one T0 – Control. The treatments were laid out in a randomized block design with three replications. The soil of the experimental site was sandy loam in texture, with bulk density 1.48 g/cm3, field capacity 24.45%, PWP 11.20%, water holding capacity 35.35%, organic carbon 0.53%, acidic in reaction (pH-5.1) and medium in available nitrogen (274.20 kg/ha), phosphorus (26.95 kg/ha) and potassium (192.00 kg/ha). A toria variety TS-67 was sown following all recommended practices of the crop. Results revealed that the growth parameters viz., plant height and dry weight of plants recorded at 30 DAS, 60 DAS and at harvest, plant population per unit area and number of primary, secondary as well as total branches per plant, the yield attributes viz., number of siliquae/plant, seeds/silqua and seed and stover yield of rapeseed were significantly higher with the application of vermicompost 2.5 t/ha + poultry manure 2.5 t/ha + mustard oil cake 1 t/ha followed by FYM 5 t/ha + poultry manure 2.5 t/ha + mustard oil cake 1 t/ha over most of the other organic sources of nutrients and control. The increase in seed yield due to the said treatments were 330.7% and 307.2%, respectively over the control and on an average 45.5% and 37.5%, respectively over other organic sources of nutrients. The oil yield due to the said treatments was also significantly higher by 346.2% and 324.6%, respectively over the control. Significantly higher N, P and K contents and their uptake by both seed and stover of rapeseed under the said treatments were recorded over other organic sources of nutrients and the control. Application of FYM, poultry manure and vermicompost either alone or in combination with mustard oil cake significantly reduced the weed population/m2 over other organic sources of nutrients and the control but increased the N, P and K contents in weeds over the control. However, due to the lower dry weight of weeds, significantly lower uptake of such nutrients by weeds were recorded with the treatment FYM 5 t/ha + vermicompost 2.5 t/ha + mustard oil cake 1t/ha (T7) followed by vermicompost 2.5 t/ha + poultry manure 2.5 t/ha (T6) compared to other organic sources of nutrients and control. Application of organic nutrient sources also considerably increased the soil moisture contents recorded from two different depths viz., 0-20 cm and 20-40 cm of the profile at flowering and siliquae development stages over the control. The highest cost of cultivation and gross return was recorded with the treatment vermicompost 2.5 t/ha + poultry manure 2.5 t/ha + mustard oil cake 1 t/ha (T9) followed by the treatment FYM 5 t/ha + poultry manure 2.5 t/ha + mustard oil cake 1 t/ha (T8). The highest B: C ratio (3.600) was recorded with the treatment FYM 10 t/ha (T1), but the highest additional net profit of Rs. 39180 was recorded under FYM 5 t/ha + poultry manure 2.5 t/ha (T5) over the control (T0).ThesisItem Open Access NUTRIENT AND WEED MANAGEMENT IN RAINFED TORIA BY ORGANIC METHODS(AAU, Jorhat, 2020-07) Borah, Prostuti; Choudhary, J.K.An experiment entitled “Nutrient and weed management in rainfed toria by organic methods” was conducted at Instructional-cum-Research Farm, Assam Agricultural University, Jorhat during the rabi season of 2019-2020 to study the effect of nutrient management (NM) and weed management (WM) by organic methods on growth and yield of toria. The experiment was laid out in randomized block design (factorial) with three replications. The treatments consisted of three nutrient management treatments viz., control (N0), application of vermicompost 2.5 t/ha (N1) and application of vermicompost 5.0 t/ha (N2) and three weed management treatments viz., control (W0), hand weeding at 30 DAS (W1) and dryland weeder operation at 30 DAS (W2). The soil of the experimental site was sandy loam in texture, acidic in reaction (pH: 5.1), medium in organic carbon (0.58%), available N (270.86 kg/ha), P2O5 (21.87 kg/ha) and K2O (169.82 kg/ha). The weeds of the experimental fields were Cynodon dactylon, Eleusine indica, Paspalum conjugatum, Panicum repens, Axonopus compressus among grasses ; Cyperus rotundus the sedge and Commelina benghalensis, Ageratum houstonianum, Mimosa pudica, Acmella euliginesa, Gynura bicolor, Oxalis corniculata, Alternanthera philoxeroides and Chenopodium album among the broad leaved weeds. The density and dry weight of weeds in rainfed toria were found to be significantly lesser with application of 5.0 t/ha vermicompost compared with other treatments. As a result, the content and uptake of N, P and K by weeds were found to be significantly lesser with N2. The growth parameters like plant height, number of primary branches/plant, number of secondary branches/plant and yield attributing characters viz., number of siliquae/plant, number of seeds/siliqua were found to be significantly improved in N2. The highest seed yield (929.26 kg/ha), stover yield (1997.95 kg/ha) was recorded with this treatment. The oil content, oil yield, N, P and K content and uptake also increased with N2. In respect of weed management, dryland weeder operation at 30 DAS (W2) was found to significantly lower the density and dry weight. N, P and K content and uptake of weeds in rainfed toria. The growth and yield attributing characters of rainfed toria improved significantly with this treatment which recorded the highest seed (755.67 kg/ha) and stover (1750.18 kg/ha) yields. Oil content, oil yield, N, P and K content and uptake also increased with W2. NM interacted significantly with WM in respect of seed and stover yields of toria. The combination of N2W2 was found to be superior with 1038.28 kg/ha and 2217.17 kg/ha seed and stover yield. The treatment combination N2W2 resulted in higher gross return (Rs. 67,082.69 /ha), net return (Rs. 43,379.69 /ha) and the benefit: cost ratio (1.83).ThesisItem Open Access IRRIGATION SCHEDULING IN RAPESEED USING CAN EVAPORIMETER(AAU, Jorhat, 2020-07) BHARADWAJ, KRISHNA; Pathak, K.A 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.ThesisItem Open Access INTERCROPPING OF BUCKWHEAT AND LATHYRUS IN RICE FALLOW UNDER ORGANIC ECOSYSTEM(AAU, Jorhat, 2020-09) BORDOLOI, NAYAN JYOTI; Goswami, JogeshAn experiment entitled “Intercropping of buckwheat and lathyrus in rice fallow under organic ecosystem” was conducted at instructional-cum-research farm, Assam Agricultural University, Jorhat during the rabi season of 2017-18 with the objective to evaluate efficient proportion of intercrops under organic management system in rice fallow land and to monitor soil physico-chemical properties as influenced by different intercrops. The experiment was laid out in randomised block design with 3 replications. The experiment was consisted of nine different treatment combinations namely T1 [Sole buckwheat]; T2 [Sole lathyrus as grain ]; T3 [Sole lathyrus as fodder ];T4 [Buckwheat + Lathyrus as grain (1:1)]; T5 [Buckwheat + Lathyrus as fodder (1:1)]; T6 [Buckwheat + Lathyrus as grain (2:1)]; T7 [Buckwheat + Lathyrus as fodder (2:1)]; T8 [Buckwheat + Lathyrus as grain(2:2)] and T9 [Buckwheat + Lathyrus as fodder (2:2)]. The soil was sandy loam with high in organic C (0.77 %). The initial nutrient content of the soil were, N (296.56 kg/ha), P2O5 (34.88 kg/ha) and K2O (148.32 kg/ha). The present investigation revealed that the yield of buckwheat, lathyrus grain and lathyrus fodder was highest in respective sole treatments and decreased with increasing share of intercrops [1,088.71kg/ha (for buckwheat)], 465.34kg/ha (for lathyrus grain), 6023.60 kg/ha (for lathyrus fodder)]. Among different intercropping systems highest buckwheat equivalent yield was obtained in buckwheat + lathyrus as grain at a ratio of 2:2. In terms of intercropping advantage measured by land equivalent ratio (LER), three intercropping viz T8 [Buckwheat + Lathyrus as grain(2:2)]; T9 [Buckwheat + Lathyrus as fodder (2:2)] and T5 [Buckwheat + Lathyrus as fodder (1:1)] showed superior performance over the sole croppings. However, intercropping of buckwheat + lathyrus as grain in 2:2 ratio recorded highest LER values over the other intercropping systems indicating intercrop advantage. Intercropping of buckwheat + lathyrus as grain at 2:2 row proportion proved to be the best since it recorded highest K value (3.32) indicating better complementary effect. Overall soil health as measured by soil available N, P and K content and organic carbon after harvest of test crops was not affected much due to sole and intercropping systems. Among different treatments, the highest cost of cultivation (₹25,100.00) was recorded in sole buckwheat. Among the intercroppings, the highest gross return (₹77,237.75.00), net return (₹55,024.75.00) and B:C (2.48) were obtained in buckwheat + lathyrus as (G) in 2:2. This study showed that among the sole cropping treatments, buckwheat was found to be the best crop under rice fallow land organic ecosystem. As a whole intercropping of buckwheat with lathyrus as grain in 2:2 ratio found to be the best in respect of buckwheat equivalent yield, biological efficiency and economic point of view. Since the findings are based on one year experimentation, further validation in farmers field will be helpful for generating best technology under fallow land organic ecosystem.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 INTEGRATED NUTRIENT MANAGEMENT IN SUMMER MAIZE (Zea mays)(AAU, Jorhat, 2020-11) Bezboruah, Minakshi; Dutta, RinjumoniA field experiment entitled “Integrated nutrient management in summer maize (Zea mays)” was carried out at Instructional-cum- Research (ICR) Farm, Assam Agricultural University, Jorhat during the year 2019 to find out the effect of INM practice to the growth and yield of summer maize and to study the post-harvest nutrient status of soil as affected by different INM practices. The experiment was laid out in randomized block design with nine treatments and replicated thrice. The treatments consisted of both soil and foliar application of fertilizers viz., T1 [60-40-40 kg/ha NPK (RDF)], T2 [RDF + Azospirillum + PSB], T3 [RDF + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS], T4 [75% N of RDF + 25% of N replaced by vermicompost], T5 [75% N of RDF + 25%of N replaced by vermicompost + Azospirillum + PSB], T6 [75% N of RDF + 25% of N replaced by vermicompost + Azospirillum + PSB + 2 sprays of vermiwash at 25&40 DAS], T7 [50% N of RDF+ 50% of N replaced by vermicompost], T8 [50% N of + 50% of N replaced by vermicompost + Azospirillum + PSB], T9 [50% N of RDF + 50% of N replaced by vermicompost + Azospirillum + PSB + 2 sprays of vermiwash at 25&40 DAS]. The soil of the experimental site was sandy loam in texture, acidic in reaction, medium in organic carbon (0.72%), low in available N (156.19 kg/ha) and medium in available P2O5 (23.78 kg/ha), and K2O (161.50 kg/ha). N was applied in two split doses one at knee high stage and second application was before tasseling. The maize seeds of the variety VMH-53 was sown on 15th of March (2019) and harvested by two picking on 10th June and 15th June. Experimental findings revealed that INM practices influenced both the growth and yield attributing characters. Application of RDF + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS (T3) recorded highest values for all the growth attributing parameters. Similarly, the yield attributing characters like weight of cob with and without husk, length of cob, number of rows per cob, grain per row, grain per cob, weight of grain per cob and nutrient (NPK) uptake was observed to be highest under RDF + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS (T3) which was at par with 75% N of RDF+ 25% of N replaced by vermicompost + Azospirillum + PSB + 2 sprays of vermiwash at 25&40 DAS. Likewise, the highest grain and stover yield being 43.04 q/ha and 89.66 q/ha respectively was produced from RDF + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS (T3) which was at par with the grain 6 yield 41.81 q/ha and stover yield 87.42 q/ha obtained from 75% N of RDF+ 25% of N replaced by vermicompost + Azospirillum + PSB + 2 sprays of vermiwash at 25&40 DAS (T6). However, the protein content in maize and nutrient content in soil after harvest was found to be non-significant. In terms of economics, the highest gross return (` 96765), net return (` 77705) and the B:C ratio (4.08) was recorded from the treatment RDF + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS (T3)and which was nearly followed by the treatment75% N of RDF + 25% of N replaced by vermicompost + Azospirillum + PSB + 2 sprays of vermiwash at 25 & 40 DAS (T6).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.
