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ThesisItem Open Access Resource conservation through crop establishment methods and weed management practices in winter rice (Oryza sativa L.) - garden pea (Pisum sativum var. hortense) relay cropping system(2023) Bhattacharjya, Sameeron; Deka, J.A field experiment was conducted at the farmers’ field at Pirakata Brahmin gaon under the jurisdiction of Krishi Vigyan Kendra, Jorhat with a view to study the resource conservation through crop establishment methods and weed management practices in winter rice (Oryza sativa. L.) - garden pea (Pisum sativum var. hortense) relay cropping system during 2019-20 & 2020-21. The treatment consisted of four crop establishment methods of winter rice (T) viz., T1 : WDSR (Broadcasting), T2 : WDSR (Modified Drum Seeder with furrow opener), T3 : PTR (Farmers’ Practice), T4 : PTR (Mechanized Transplanting by paddy transplanter) where WDSR: Wet Direct Seeded Rice, PTR: Puddled Transplanted Rice along with three weed management practices of rice (W) viz., W0 : Weedy check, W1 : Pretilachlor 0.75 kg/ha as pre-emergence fb bispyribac-sodium 0.025 kg/ha (20 DAS/DAT) as post-emergence, W2: Pretilachlor 0.75 kg/ha as pre-emergence fb manual weeding (30 DAS/DAT). The experiment was laid out in a factorial randomized block design with three replications. The soil of the experimental site was sandy clay loam in texture, medium acidic in reaction, mediumin organic carbon and available N and low in available P2O5 and K2O. The study revealed that establishment method i.e. T3: PTR (FP) resulted lower weed growth during 30 DAS in winter rice but T2: WDSR (Drum Seeder) had lower weed growth in subsequent growth stages at par with T3: PTR (FP) and T4: PTR (MTR). It was found that T2, T3 and T4 had higher growth and yield parameters of the crop as compared to T1 : WDSR (B) which resulted higher grain and straw yield of winter rice as well as uptake of nutrients. The highest grain yield of 49.79 and 50.13 q/ha of winter rice was recorded under T4 : PTR (MTR) followed by 46.62 and 47.8 q/ha in T2 : WDSR (Drum seeder) during 2019 and 2020, respectively. Among the weed management practices, i.e. W1: Pretilachlor 0.75 kg/ha as pre-emergence fb. Bispyribac-sodium 0.025 kg/ha (20 DAS/DAT) as post-emergence and W2: Pretilachlor 0.75 kg/ha as pre-emergence fb manual weeding (30 DAS/DAT) recorded lower weed growth and nutrient uptake with higher weed control efficiency (WCE) and weed control index (WCI) during active growth period of winter rice. This resulted into higher crop growth characteristics and yield parameters which ensured higher grain and straw yield as well as uptake of nutrients by winter rice. The percent increase in grain yield of winter rice in W1 and W2 as compared to W0 (control) was 82.97, 84.52 in 2019 and 81.62, 81.58, respectively in 2020. The treatment combination T4W2 recorded highest grain and straw yield of winter rice which was statistically at par with T4W1, T2W1 and T2W2. The higher B:C of 2.27 and 2.14 was recorded in T2W1 with higher gross return and net return followed by T2W2 (2.18 and 2.08 during 2019 and 2020, respectively). In case of relay garden pea, no significant difference in green pod yield and stover yield was recorded due to rice establishment methods and weed management practices. Highest green pod yield of 18.54 and 19.10 q/ha was recorded under rice establishment method T4: PTR (MTR) during 2019-20 and 2020-21, respectively. Weed management practice W1 resulted higher green pod yield of 18.23 q/ha during 2019-20 whereas W2 resulted higher green pod yield of 18.36 q/ha during 2020-21. Soil physico-chemical properties like bulk density, water holding capacity, carbon stock of soil at 0-15 cm and 15-30 cm depth, available N, P2O5 and K2O were significantly improved under rice establishment method PTR (MTR). Cost benefit analysis of the winter rice–relay garden pea cropping system revealed that among different treatment combinations highest B: C was registered in T2W1 (2.67 and 2.51) followed by T2W2 (2.49 and 2.37) during 2019-20 and 2020-21, respectively.ThesisItem Open Access EVALUATION OF TILLAGE, PLANT GROWTH PROMOTING BACTERIA AND WEED MANAGEMENT PRACTICES IN UPLAND DIRECT SEEDED RICE(2023) PHUKAN, JIMNI; Deka, JayantaA field experiment entitled “Evaluation of tillage, plant growth promoting bacteria and weed management practices in upland direct seeded rice” was carried out during 2020 and 2021 at Instructional-Cum-Research (ICR) Farm, Assam Agricultural University, Jorhat to evaluate the effect of different tillage, plant growth promoting bacteria and weed management practices on weed, crop and soil properties. The experiment comprising 20 treatment combinations with 2 tillage practices, viz., T1: conventional tillage, T2: reduced tillage up to 50%; 2 plant growth promoting bacteria treatments, viz., P1: Pseudomonas fluorescens, P2: no inoculation and 5 weed management practices, viz., W1: Sesbania aculeata mulching, W2: brown manuring with Sesbania aculeata, W3: pretilachlor @ 0.75 kg/ha followed by bispyribac-sodium @ 0.025 kg/ha at 30 DAS, W4: mechanical weeding at 20 and 40 DAS, W5: weedy check, laid out in a split-plot design with tillage and plant growth promoting bacteria treatments in main plot and weed management practices in sub-plots replicated thrice. The soil of the experimental site was sandy loam, acidic in reaction (pH 5.5), medium in organic carbon (0.60 %), available N (280.60 kg/ha), available P2O5 (22.28 kg/ha) and low in available K2O (128.07 kg/ha). The initial bulk density, total porosity as well as water holding capacity of the soil at 0-15 and 15-30 cm soil depth were 1.43 and 1.50 g/cc, 44.96 and 42.31% and 43.10 and 41.02 %, respectively. Among tillage practices, conventional tillage resulted in the lower weed growth throughout the crop growth period and the higher crop growth characteristics as well as yield parameters of upland direct seeded rice as compared to reduced tillage up to 50%. The per cent increase in grain yield of upland direct seeded rice under conventional tillage over reduced tillage up to 50% were to the tune of 16.60 and 17.91 in 2020 and 2021, respectively. Among, plant growth promoting bacteria treatments, Pseudomonas fluorescens inoculation recorded better crop growth characteristics as well as yield parameters leading to better weed suppression as compared to no inoculation. The per cent increase in grain yield under Pseudomonas fluorescens inoculation compared to no inoculation was to the tune of 8.38 in 2020 and 8.84 in 2021. Among different weed management treatments, pretilachlor @ 0.75 kg/ha followed by bispyribac-sodium @ 0.025 kg/ha at 30 DAS and brown manuring with Sesbania aculeata recorded the lower weed growth and nutrient uptake by weeds with higher WCE and WCI during active crop growth period which resulted into the higher crop growth characteristics and yield parameters ultimately reflecting in the higher grain and straw yields with higher nutrient uptake by the crop. The corresponding per cent increase in grain yield of crop in pretilachlor @ 0.75 kg/ha followed by bispyribacsodium @ 0.025 kg/ha at 30 DAS and brown manuring with Sesbania aculeata compared to weedy check was 188.99 and 175.62 in 2020 and 189.24 and 174.85 in 2021, respectively. Treatment combination of conventional tillage either with pretilachlor @ 0.75 kg/ha fb bispyribac-sodium @ 0.025 kg/ha at 30 DAS or brown manuring with Sesbania aculeata recorded higher grain and straw yields as compared to other treatment combinations. Soil physico-chemical and biological properties like carbon stock, periodical soil moisture content, available N, P2O5 and K2O, microbial population, microbial biomass carbon and maximum activity of enzymes, viz., phosphomonoesterace and dehydrogenase was recorded in reduced tillage up to 50% compared to conventional tillage. However, bulk density, total porosity and water holding capacity were better under conventional tillage. Among plant growth promoting bacteria treatments, Pseudomonas fluorescens inoculation recorded higher availability of nutrients, microbial population, microbial biomass carbon and maximum activity of enzymes, viz., phosphomonoesterace and dehydrogenase. However, this treatment did not significantly affect the soil physical properties. The higher B-C ratio was recorded under treatment combination of conventional tillage, Pseudomonas fluorescens with pretilachlor @ 0.75 kg/ha fb bispyribac-sodium @ 0.025 kg/ha at 30 DAS (2.01 and 2.04) followed by conventional tillage, Pseudomonas fluorescens and brown manuring with Sesbania aculeata (1.97 and 2.01) in 2020 and 2021, respectively.ThesisItem Open Access RELATIVE PERFORMANCE OF NIGER VARIETIES TO DIFFERENT MICROCLIMATIC REGIMES UNDER RAINFED SITUATION(2023) Gogoi, Vaishali; Ojha, N. J.A field experiment entitled “Relative performance of niger varieties to different microclimatic regimes under rainfed situation” was conducted at Instructional-cum- Research (ICR) farm, AAU, Jorhat during rabi season of 2022-23. The experiment was laid out in split plot design with three replications. The treatments consisted of five sowing dates viz., 20th October, 5th November, 20th November, 5th December and 20th December in main plots and three varieties viz., NG-1, GA-10 and JNS-9 in sub- plots. The experimental site was sandy loam in texture with pH 5.43, medium in available N (283.14 kg/ha), available K2O (156.55 kg/ha), organic carbon (0.56%) and low in available P2O5 (18.67 kg/ha). Different growth and yield attributing characters of niger were influenced significantly due to different dates of sowing. The growth characters viz., plant height, number of leaves per plant, number of branches per plant, leaf area index, plant dry weight, crop growth rate, relative growth rate, yield attributing characters viz., number of capitula per plant (16), number of seeds per capitulum (34.66) were significantly higher in the crop sown on 20th October (D1). The nutrient content and uptake (N, P and K) was also the highest in case of D1. Significantly higher seed yield (468.33 kg/ha) and stover yield (1935.22 kg/ha) were recorded when the crop was sown on 20th October. Among the varieties, growth parameters such as plant height, number of leaves per plant, number of branches per plant, leaf area index, plant dry weight, crop growth rate, relative growth rate, yield attributing characters such as number of capitula per plant (14.46), number of seeds per capitulum (32.06) and test weight (3.35g), seed yield (457.46 kg/ha), stover yield (1967.40 kg/ha) and oil yield (164.75 kg/ha) were significantly higher in the variety NG-1 (V1) over the other two varieties viz., GA-10 (V2) and JNS-9 (V3). However, significantly higher oil content was obtained in the variety GA-10 (37.61 %). Treatment combination of sowing of variety NG-1 on 20th October (D1V1) recorded the highest interaction effect in case of number of capitula per plant (17.66), seed yield (511.33 kg/ha), oil yield (164.75 kg/ha) and N- uptake by seeds (14.50 kg/ha). In terms of economics, the highest gross return (₹ 31138/ha), net return (₹ 18999/ha) and B-C ratio (1.57) were recorded when the variety NG-1 was sown on 20th October (D1V1). This was followed by sowing of variety JNS-9 on 20th October (D1V3) with gross return (Rs. 29030/ha), net return (₹ 16891/ha) and B-C ratio (1.39).ThesisItem Open Access INTEGRATED WEED MANAGEMENT IN SUMMER MAIZE (Zea mays L.)(2023) Narah, Tulika; Kurmi, K.A field experiment on “Integrated weed management in summer maize (Zea mays L.)” was carried out during summer, 2022 at the Instructional-cum-Research (ICR) farm, AAU, Jorhat, with the objectives of identifying the weed flora during the crop growth period; the best weed management practice in the crop and to understand the effect of the weed management practices on the soil physical, chemical and microbial population. A total of ten treatments were taken for the research which included - T1:Farmers practice i.e. manual weeding, T2: Recommended practice (Atrazine 1kg ha-1 PE), T3:Weedy fallow, T4: PE application of atrazine 0.5 kg ha-1 followed by PoE application of tembotrione 120 g ha-1, T5: Live mulching with cowpea, T6:Live mulching with greengram, T7: Mulching with lemongrass, T8:Mulching with biodegradable polythene, T9:Weedy Check and T10:Weed free check.The experiment was laid down in Randomized Block Design (RBD) with three replications. The soil of the experimental plot was of sandy loam texture with a pH of 5.1, available N in the medium range (286.54 kg ha-1), available P2O5 and K2O in low range with 24.37 kg ha-1 and 158.82 kg ha-1, respectively. The results of the experiment revealed that the PE application of atrazine 0.5 kg ha-1 followed by PoE application of tembotrione 120 g ha-1 (T4) has been able to control the weeds more effectively than the other treatments at the early stage of crop growth. However, during the later stage of crop growth more effective management of weeds was seen under mulching with lemongrass (T7). Mulching with lemongrass (T7) showed higher result with regards to crop growth parameters viz., Plant height, dry matter accumulation,crop growth rate, number of leaves plant-1 and leaf area index at all the stages as compared to rest of weed management treatments. Mulching with lemongrass(T7) also showed higher result in terms of yield attributing characters viz., number of cobs plant-1, cob length, cob girth, 1000 grain weight. Grain yield (69.15 q ha-1) was found to be significantly higher in mulching with lemongrass(T7). Significantly higher cob yield with husk(93.34 q ha-1) and cob yield without husk (90.68 q ha-1) was recorded in mulching with lemongrass(T7). Similarly straw yield (95.97 q ha-1) was found to be highest in mulching with lemongrass(T7). The NPK content and uptake by grain and stover of the crop was highest in mulching with lemongrass(T7).Mulching with lemongrass also recorded higher values of the soil available N, P2O5, K2O. The microbial population after harvest showed significantly higher population of microbes in mulching with lemongrass, as compared to the other treatments with a value of 6.77 log cfu g-1 soil for bacterial population and 4.74 log cfu g-1 soil for fungal population. The highest gross and net returns (Rs 168615 ha-1 and Rs 115308 ha-1, respectively ) were noted in mulching with lemongrass(T7) along with highest B:C (2.16) closely followed by PE application of atrazine 0.5 kg ha-1 followed by PoE application of tembotrione 120g ha-1 (T4).ThesisItem Open Access EFFICACY OF HERBICIDE COMBINATIONS FOR WEED MANAGEMENT IN DIRECT SEEDED KHARIF RICE(2023) Beypi, Mirdan; Kalita, SontaraA field experiment entitled “Efficacy of herbicide combinations for weed management in direct seeded kharif rice” was carried out in Instructional-cum-Research farm, Assam Agricultural University, Jorhat during kharif, 2022.The Randomized Block Design was used to arrange 12 weed management treatments in 3 replications. The treatments were weed free (T1), weedy check (T2), bispyribac-sodium 25g/ha + pyrazosulfuron 20g/ha 20 days after sowing (DAS) as check (T3), pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4), pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5), pretilachlor 750g/ha pre-emergence followed by penoxsulam 30 g/ha + bentazone 1080 g/ha 20 DAS (T6), glyphosate 1000 g/ha followed by one mechanical weeding 30 DAS (T7), glyphosate 1000 g/ha followed by fenoxaprop-p-ethly 50g/ha + ethoxysulfuron 15g/ha 20 DAS (T8), glyphosate 1000 g/ha followed by triafamone + ethoxysulfuron 60g/ha at 20 DAS (T9), glyphosate 1000g/ha followed by penoxsulam 30g/ha + bentazone 1080g/ha 20 DAS (T10), hand weeding at 20 DAS and weeding with grubber at 40 DAS (T11) and two mechanical weeding at 20 and 40 DAS (T12). The texture of the soil was sandy loam with pH of 5.5, bulk density of 1.40 Mg/m3, organic carbon of 0.67% and available N, P2O5 and K2O of 289.93, 19.69 and 114.11 kg/ha, respectively. All treatments significantly lowered the weed density as well as dry matter in terms of broad-leaved, sedge and grassy weeds at 60, 90 and 120 DAS and at harvest as compared to weedy check. Significant reduction (75.59, 56.97, 44.77 and 30.44 %, respectively) in density of total weeds was observed in treatment (T5) pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS at 60, 90 and 120 DAS as well as at harvest over weedy check. The same treatment recorded significantly lower dry matter of total weeds at 60, 90 and 120 DAS and at harvest to the tune of 73.39, 52.71, 37.76 and 27.46 %, respectively over weedy check. Pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) showed higher result with regards to crop growth parameters viz., plant height, number of tillers/m2, leaf area index, dry matter accumulation/m2 and crop growth rate at all the stages as compared to rest of weed management treatments except for plant height which was found to be not significant at 30, 120 DAS and at harvest. The above-mentioned treatment also showed higher result in terms of yield attributing characters viz., number of panicles/m2 and number of grains/panicle with 77.60 and 40.97 % increase over weedy check. In case of panicle length and test weight, the result was found to be not significant among all the treatments. Grain yield was found to be significantly higher in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) with 175.16 % higher over weedy check and was at par with pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4). Similar result was observed in terms of straw and biological yield with 137.38 and 152.37 %, respectively increase over control. In case of straw yield (50.68 kg/ha) T5 was at par with T4 (46.65 kg/ha) and T6 (44.85 kg/ha). Weed management treatment did not significantly affect harvest index of direct seeded kharif rice. The lower weed index was recorded in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) (5.84 %) followed by pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4) (13.30 %) and pretilachlor 750g/ha pre-emergence followed by penoxsulam 30 g/ha + bentazone 1080 g/ha 20 DAS (T6) (17.49%). No significant change in N, P and K content was recorded in grain and stover whereas N, P and K uptake by the crop was significantly higher in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5). The mentioned treatment decreased N, P and K content in weeds and their uptake as compared to weedy check by 5.18, 22.08 and 6.78, and 50.18, 59.02 and 50.76 %, respectively over weedy check. The same treatment recorded higher available N, P2O5 and K2O by 7.55, 19.57 and 3.96 %, respectively over weedy check. Weed management treatment did not significantly affect soil organic carbon of direct seeded kharif rice. The highest gross and net returns (103541 and 62751 ₹ /ha, respectively) were noted by pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) along with the highest B-C ratio (1.54) closely followed by pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4) (1.36).ThesisItem Open Access CONSERVATION AGRICULTURE PRACTICES IN RICE-LINSEED CROPPING SEQUENCE(2023) Maurya, Manish Kumar; Rafique, Nawab TayabA field experiment entitled “Conservation agriculture practices in rice-linseed cropping sequence” was conducted at Instructional cum Research (ICR) farm, AAU, Jorhat during kharif, 2022 and rabi season, 2022-2023. The experiment consisted of three objective viz. (i) to study the effect of rice establishment methods on growth and productivity of rice and on succeeding linseed crop, (ii) to examine the effect of kharif rice stubble managements on performance of linseed crop and (iii) to assess the economics of the rice based double cropping system as influenced by rice establishment methods and stubble management practices. The experiment consisted of three rice establishment methods viz. transplanting (M1), wet-DSR (M2) and dry-DSR (M3) in main-plot and four stubble management practices viz. no residue (S1), 15 cm tall stubble chopped (S2), 15 cm tall stubble unchopped (S3) and 30 cm tall stubble chopped (S4) in sub-plot. The experiment was laid out in split-plot design with three replications. The soil at experimental site was sandy loam in texture with a pH of 5.1 and 5.26, medium in availability of nutrients including N (282.4 and 279.09 kg ha-1), P2O5 (23.86 and 24.79 kg ha-1), K2O (128.4 and 126.5 kg ha-1) and organic carbon content (0.51 and 0.53%) in Kharif and rabi season, respectively. The total rainfall received during kharif and rabi season was 1267.9 and 278.5 mm, respectively. The mean maximum and minimum temperature during kharif season ranged from 28.2 to 34.90C and 10.9 to 25.60C, respectively while during rabi season, they ranged from 21.4 to 31.90C and 7.9 to 20.50C, respectively. Different growth and yield attributing characters, as well as the yield of rice, were significantly influenced by rice establishment methods. All the growth and yield attributing characters were significantly higher in transplanting (M1) over wet-DSR and dry-DSR. The highest grain yield (5.17 t ha-1) and straw yield (7.04 t ha-1) were also recorded with transplanting (M1). Similarly, different growth and yield attributing characters, as well as the seed yield of linseed were significantly influenced by rice establishment methods and stubble management practices. All the growth and yield attributing characters were significantly higher where linseed was grown following the dry-direct-seeded rice (M3). The highest seed yield (5.28 q ha-1) and stover yield (11.29 q ha-1) were also recorded where linseed was grown following the dry-direct-seeded rice (M3). Similarly, among the stubble management practices, growth and yield attributes were significantly higher where linseed was grown following 30 cm tall rice stubble chopped (S4). The highest seed yield (5.72 q ha-1) and stover yield (11.53 q ha-1) were also recorded where linseed was grown following 30 cm tall rice stubble chopped (S4). The highest cost of cultivation (₹ ha-1 76169.46) in the rice-linseed cropping system was incurred where linseed was grown after transplanted rice with 30 cm tall stubble chopped (M1S4). The highest gross return (₹ ha-1 137376.7) and net return (₹ ha-1 61207.21) were obtained by the treatment combination of linseed grown after transplanted rice with 30 cm tall stubble chopped (M1S4). However, the maximum benefit-cost ratio was recorded where linseed succeeded wet-direct-seeded rice with 30 cm tall rice stubble unchopped (2.02:1) followed by linseed grown after wet-direct-seeded rice with 30 cm tall stubble chopped (1.95:1). From the point of view of the rice-linseed cropping system, the best combination in terms of rice equivalent yield (6668.77 kg ha-1) was obtained by linseed following transplanted rice with 30 cm rice stubble chopped (M1S4).ThesisItem Open Access EVALUATION OF ORGANIC AND NATURAL FARMING PRACTICES ON CROP PRODUCTIVITY AND SOIL IN KHARIF RICE(2023) Dutta, Saurav Kumar; Saud, Ranjit KumarA field experiment entitled “Evaluation of organic and natural farming practices on crop productivity and soil in kharif rice” was conducted in research farm of AAU-ARRI, Titabar during the sali season of 2022-23 with a view to study the growth, yield behaviour, soil conditions of scented rice (variety: Bokul joha) under different organic and natural farming treatments. The experiment was laid out in randomized block design with three replications. The treatments consisted of eight in total viz. absolute control(T1), complete natural farming (beejamrit + ghanajeevamrit + jeevamrit mixture at 300 litres/ha at 30, 60 and 90 DAT) (T2), enriched compost 5 t/ha + biofertilizer (Azospirillum, PSB 4 kg/ha as seedling root dip (T3), enriched compost 5 t/ha (T4), vermicompost 5 t/ha (T5), enriched compost 2.5 t/ha + vermicompost 2.5 t/ha (T6) , fresh azolla at 400 kg/ha as dual crop + biofertilizers (Azospirillum, PSB and KSB mix at 4 kg/ha as seedling root dip) (T7), vermicompost at 1 t/ha mixed inocula of Azospirillum amazonense A-10 and Bacillus megaterium P-5 4 kg/ha and rock phosphate 10 kg/ha P2O5 (T8). The treatments brought significant influences on the various growth and yield attributing characters. Among the different treatments, the highest plant height, dry matter, leaf area index and number of tillers at different intervals were found in the vermicompost @ 1t/ha mixed inocula of Azospirillum amazonense A-10 and Bacillus megaterium P-5 4 kg/ha and rock phosphate 10 kg P2O5. The highest grain (34.62 q/ha) and straw yield (15.50 q/ha) were also obtained from application of vermicompost 1t/ha (on dry weight basis) mixed inocula of Azospirillum amazonense A-10 and Bacillus megaterium P-54 kg/ha rock phosphate @ 10 kg/ha P2O5 (T8) followed by the treatment including fresh azolla @ 400 kg/ha as dual crop + biofertilizers (Azospirillum, PSB and KSB mix @ 4 kg/ha as seedling root dip) (T7). In case of the soil, residual N (272.09 kg/ha) was found to be significantly high in fresh azolla at 400 kg/ha as dual crop + biofertilizers (Azospirillum, PSB and KSB mix at 4 kg/ha as seedling root dip) (T7) whereas P2O5 (22.8 kg/ha) and K2O (123.17 kg/ha) were found to be highest in vermicompost 1t/ha (on dry weight basis) mixed inocula of Azospirillum amazonense A-10 and Bacillus megaterium P-54 kg/ha rock phosphate @ 10 kg/ha P2O5 (T8). An economic analysis showed that the highest net return (₹ 1,40,779/ha), gross return (₹ 1,60,305 /ha) and highest B:C ratio of 1.95 was recorded in the treatment comprising of vermicompost application of 1t/ha and mixed inocula of Azospirillum amazonense A-10 and Bacillus megaterium P-5 at 4 kg/ha and rock phosphate 10 kg/ha P2O5.ThesisItem Open Access SMART NUTRIENT MANAGEMENT WITH NANO UREA ON RABI MAIZE (Zea mays L.) UNDER RAINFED SITUATION(2023) Singh, Rajib; Kalita, R.A field experiment was carried out during rabi, 2022-23 at the experimental plot of the Department of Agronomy, B. N. College of Agriculture, Assam Agricultural University, Biswanath Chariali to assess “Smart nutrient management using nano urea on rabi maize (Zea mays L.) under rainfed situation” with two objectives viz. studying the effect of foliar application of nano-urea on growth and yield of rabi maize and to find out the optimum combination of nano-urea and with conventional urea. The experiment consisted of 11 treatments in randomized block design viz. T1: Recommended Dose of Fertilizer (RDF) T2: 100% P & K + Spray of Nano urea @ 6 ml l-1 at knee high and tasseling stage, T3: 100% P & K + Spray of Nano urea @ 8 ml l-1 at knee high and tasseling stage, T4: 100% P & K + Spray of Nano urea @ 10 ml l-1 at knee high and tasseling stage, T5: 25% N + 100% P & K + Spray of Nano urea @ 6ml l-1 at knee high and tasseling stage, T6: :25% N + 100% P & K + Spray of Nano urea @ 8ml l-1 at knee high and tasseling stage, T7: 25% N + 100% P & K + Spray of Nano urea @ 10ml l-1 at knee high and tasseling stage, T8: 50 % N + 100% P & K + Spray of Nano urea @ 6 ml l- 1 at knee high and tasseling stage, T9: 50 % N + 100% P & K + Spray of Nano urea @ 8 ml l-1 at knee high and tasseling stage, T10: 50 % N + 100% P & K + Spray of Nano urea @ 10 ml l-1 at knee high and tasseling stage, T11: 100% P & K. The results of the investigation revealed that the treatment T1 (RDF) resulted in relatively taller plant height (103.20 cm) at knee high stage which is statistically at par with T8, T9 and T10. However, the highest plant height during tasseling (245.20 cm) and physiological maturity (243.80 cm) was observed in T8 (50% of recommended dose of N from conventional urea + spraying Nano urea @ 6 ml l-1 at knee high and tasseling stage). T1 also registered the significantly higher number of green leaves (8.73) plant-1, dry matter accumulation (138.83 g) and leaf area index (1.84) at knee high stage. Conversely, in later stage of growth, effect of nano urea was found to be significant with notably higher value of number of green leaves plant-1 (11.67 and 9.60); leaf area index (4.63 and 3.10 plant-1) and dry matter accumulation (214.76 and 645.26 g plant-1) recorded at tasseling and physiological maturity, respectively under T8. The crops under this treatment also showed the significantly thicker stem (7.53 cm). Crops receiving 50 % N from conventional urea and 6 ml l-1 of nano urea recorded greater crop growth rate (CGR) between knee high and tasseling (209.79 g m-² day-1) and between tasseling and physiological maturity (638.10 g m-² day-1). In case of, relative growth rate (RGR), higher value (0.32 g g-1 d-1) was recorded under T6 that receiving 25% recommended N from conventional source and 6ml l-1 of nano urea in between knee high to tasseling; whereas between tasseling to physiological maturity stage the highest value (0.47 g g-1d-1) was found in T8. The effect of nano urea was also observed with respect to leaf chlorophyll content and relative water content (RWC) of leaf as the highest being 1.37 mg g-1 fw. and 91.23 %, respectively recorded under T8 . Effect on yield parameters revealed significantly influence of nano urea with respect to increased length (35.88 cm), weight (368 g) and girth (20.29 cm) of cob together with more number of seeds per cob (615.93) and test weight (247.54 g) which were recorded under T8. The improvement of these yield parameters was reflected in grain yield (72.25 q ha-1), stover yield (110.67 q ha-1) and harvest index (39.50 %) and production efficiency (120.42 %) as well. The soil available nitrogen was highest (268.75 kg ha-1) in T10 (50 % N + 100% P & K + spray of Nano urea @ 10 ml l-1), however T1 (RDF), T8 (50 % N + 100% P & K + Spray of Nano urea @ 6 ml l-1) and T9 (50 % N + 100% P & K + Spray of Nano urea @ 10 ml l-1) showed comparable value and the lowest value (241.19 Kg ha-1) was recorded in T11 i.e. 100% P & K. Among all the treatments, T1 (RDF) recorded the highest cost of cultivation ( 80,650 ha-1) followed by T8 and, the lowest ( 75000 ha-1) was incurred in T11 i.e.100% P & K. The highest gross return (Rs. 1,50,569 ha-1), net return (Rs. 72,069 ha-1) and benefit-cost ratio (1.91) was obtained in T8 whereas, T11 i.e. 100% P & K recorded the lowest gross return (. 86,305 ha-1), net return ( 11,305 ha-1) and benefit-cost ratio (1.15). Results showed that spraying of nano urea @ 6ml/L at knee high and tasseling stage with basal application of 50% of recommended N from conventional urea with 100 % P & K was superior in terms of noticeably enhanced and economically efficient corn yield which was resulted from significantly improved growth and yield parameters. Therefore, it could be inferred that spraying of nano-urea @ 6ml l-1 at knee high and tasseling stage coupled with basal application of 50% of recommended N from conventional urea with 100 % P & K could be a promising and smart option as nutrient management strategy to harvest higher and economically efficient rabi corn yield under rainfed upland situation in Assam.ThesisItem Open Access PERFORMANCE OF AROMATIC RICE (Oryza sativa L.) UNDER NATURAL FARMING PRACTICES(2023) Bhuyan, Kishor Jyoti; Goswami, JogeshA field experiment entitled "Performance of aromatic rice (Oryza sativa L.) under natural farming practices" was conducted at the organic block of the Instructional-cum-Research Farm, Assam Agricultural University, Jorhat, during kharif, 2022–23, with a view to studying the growth, yield, quality and economics of joha rice (variety: Tulasi joha) as well as its impact on overall soil health under natural farming practices. The experiment was laid out in a Randomized Block Design (RBD) with three replications. The experiment consisted of eight different treatments of natural farming practices, viz., T1: control (no nutrient input), T2: vermicompost (*RD of N), T3: panchagavya as foliar application @ 1.5% each at 30, 60 and 90 DAT, T4: enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT, T5: jeevamrutha as foliar application @ 1.5% each at 30, 60, and 90 DAT, T6: beejamrutha as root dip treatment @ 3%, T7: vermiwash as foliar application @5% each at 30, 60, and 90 DAT, T8: green leaf manuring (5t/ha). The soil of the experimental site was sandy loam in texture, acidic (pH 5.25), medium in organic carbon (0.76%), low in available N (270.89 kg/ha) and K2O (134.76 kg/ha), and medium in P2O5 (23.90 kg/ha). The total rainfall received during the crop period was 935.9 mm. The treatments had a significant influence on the various growth, yield and quality parameters, while, a few parameters like leaf chlorophyll content, relative growth rate and L-B ratio were found to be non-significant. Among the different treatments, enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT (T4) showed significantly higher crop growth and physiological parameters such as plant height, number of tillers/m2, number of leaves/ plant, root length, root volume, root dry weight, leaf area index, leaf area duration, plant dry weight and Crop Growth Rate (CGR) at different crop growth stages, followed by vermicompost (T2) and panchagavya as foliar application @ 1.5% each at 30, 60 and 90 DAT (T3). The yield attributing characters such as number of panicles/m2, length of panicle, weight of panicle, number of filled grains/panicle and quality parameters such as length, breadth and amylose content of grains were found to be highest under the treatment enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT (T4) followed by vermicompost (*RD of N) (T2) and panchagavya as foliar application @ 1.5% each at 30, 60 and 90 DAT (T3). In the case of grain yield, enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT (T4) showed significantly higher (24.80 q/ha) results, which was at par with T2, T3, T5 and T6. However, the treatments did not have any significant variations on the straw yield or harvest index. Except for soil organic carbon, higher soil chemical properties such as available N, P2O5 and K2O at harvest were recorded in the treatment T8 consisting of green leaf manuring (5 t/ha), followed by vermiwash as foliar application @5% each at 30, 60, and 90 DAT (T7) and beejamrutha as root dip treatment @ 3% (T6), while, higher soil biological properties such as total microbial count, dehydrogenase activity and microbial biomass carbon were found in enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT, which were at par with panchagavya as foliar application @1.5% each at 30, 60, and 90 DAT (T3). An economic analysis showed that the highest net return (₹91133/ha), gross return (₹138072/ha) and highest B:C (1.94) were recorded in the treatment enriched panchagavya as foliar application @ 1.5% each at 30, 60, and 90 DAT (T4) followed by panchagavya as foliar application @1.5% each at 30, 60, and 90 DAT (T3).
