Browsing by Author "Jacob, D"

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Agronomic biofortification of zinc in rice (oryza sativa L.)
(Department of Agronomy,College of Agriculture, Vellayani, 2019) Amal Jose; Jacob, D
Impact of plant population and weed management practices on the performance of Basmati Rice
(Department of Agronomy, College of Agriculture, Vellayani, 2002) Jacob, D; Elizabeth K Syriac
Nutritional management of yellowing in arecanut
(Department of Agronomy, College of Horticulture, Vellanikkara, 2007) Jacob, D; Mercy George
Performance of semi dry rice in response to nutripriming and sowing methods in onattukkara sandy plains
(Department of Agronomy, College of Agriculture,Vellayani, 2025-01-09) Vincy Alex.; Jacob, D
The study entitled “Performance of semi-dry rice in response to nutripriming and sowing methods in Onattukara Sandy Plains” was conducted during the period 2022-2024. The objective was assessment of the influence of nutriprimed seeds sown with seed drill on the growth and yield of semi-dry rice in Onattukara Sandy Plains. The research work comprised a pot culture experiment conducted at Department of Agronomy, College of Agriculture, Vellayani and a field experiment carried out in farmer’s field at Onattukara Sandy Plains of Alappuzha district. The short duration rice variety 'Bhagya' was used in the experiments. A pot culture experiment was conducted in completely randomized design to identify three most effective nutripriming treatments for field experimentation. Ten treatments were evaluated in three replications, consisting of seeds nutriprimed with KCl 0.1% (T1), KNO3 0.1% (T2), 19:19:19 0.1% (T3), KCl 0.1% + ZnSO4 0.01% (T4), KNO3 0.1% + ZnSO4 0.01% (T5), 19:19:19 0.1% + ZnSO4 0.01% (T6), KCl 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% (T7), KNO3 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% (T8), 19:19:19 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% (T9), and hydroprimed seeds as control (T10). Nutriprimed seeds exhibited superior germination performance compared to hydroprimed control, as evidenced by higher values for germination percentage, germination index, mean daily germination, speed of germination, mean germination rate, coefficient of rate of germination, germination rate index, shoot and root length, shoot and root dry weight, seedling vigour index I, and seedling vigour index II. Conversely, these nutriprimed seeds demonstrated lower values for time spread of germination, mean germination time, and time to 50 per cent germination. Scores were assigned to each germination parameter, seedling growth and vigour index. The three treatments with the highest overall scores were advanced to field experiment. The best performing nutripriming treatments thus selected were, 19:19:19 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% (NPK+Zn+B), 101 19:19:19 0.1% + ZnSO4 0.01% (NPK+Zn), and KNO3 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% (NK+Zn+B). The field experiment was laid out in randomized block design during virippu season (May 2024 to August 2024), to evaluate the influence of various nutripriming treatments and sowing methods on the growth and yield of semi-dry rice. Eight treatments replicated thrice, included NPK+Zn+B nutriprimed seeds sown traditionally (T1), NPK+Zn+B nutriprimed seeds sown using seed drill (T2), NPK+Zn nutriprimed seeds sown traditionally (T3), NPK+Zn nutriprimed seeds sown using seed drill (T4), NK+Zn+B nutriprimed seeds sown traditionally (T5), NK+Zn+B nutriprimed seeds sown using seed drill (T6), non-nutriprimed seeds sown traditionally as control (T7), and non-nutriprimed seeds sown using seed drill as control (T8). Seeds nutriprimed with NPK+Zn+B and sown using seed drill (T2) resulted in taller plants, greater number of tillers per square metre, higher leaf area index, and increased total chlorophyll content. T2 also had higher dry matter accumulation per hill, resulting in higher crop growth rate (26.01 g m-2 d-1) and relative growth rate (0.034 g g-1 d-1) during 40 to 60 DAS. Moreover, T2 resulted in increased number of productive tillers (444 no. m-2), greater number of spikelets per panicle (127 nos.), filled grains per panicle (110 nos.), and higher grain weight per panicle (3.13 g). Treatment T2 exhibited the lowest sterility percentage (11.3%). These improved growth and yield attributes in T2 resulted in greater grain (4986 kg ha-1) and straw (6215 kg ha-1) yields, and higher harvest index (0.44). Non-nutriprimed seeds sown traditionally (T7) yielded 3114 kg ha-1 grain, while non-nutriprimed seeds sown using seed drill (T8) produced a grain yield of 3578 kg ha-1. This represented a 14.9 per cent increase in grain yield due to the use of seed drill. Seeds nutriprimed with NPK+Zn+B and sown using seed drill (T2) achieved higher grain yield (4986 kg ha-1), accounting for 39.4 per cent increase compared to T8. 102 Seeds nutriprimed with NPK+Zn+B and sown with seed drill (T2) recorded lower absolute density of weeds, resulting in lower weed dry weight. T2 also resulted in higher crop uptake of N (154kg ha-1), P (25 kg ha-1) and K (96 kg ha-1). Post harvest soil analysis revealed decreased available N, P and K (241, 34.44 and 168 kg ha-1, respectively) in T2 compared to pre-treatment levels. Among the treatments, seeds nutriprimed with NPK+Zn+B and sown using seed drill (T2) recorded the highest net income (₹ 64167 ha-1) and benefit cost ratio (1.44). From the study it was concluded that, seeds nutriprimed with 19:19:19 0.1% + ZnSO4 0.01% + Na2B8O13 0.01% and sown using seed drill is an effective method for better crop establishment and higher grain yield in semi-dry rice cultivation in the Onattukara Sandy Plains.
Weed management in semi-dry rice of semi-dry rice Onattukara sandy plains
(Department of Agronomy, College of Agriculture, Vellayani, 2024-03-14) Rachana, V R; Jacob, D
The study entitled “Weed management in semi-dry rice of Onattukara Sandy Plains” was conducted at College of Agriculture, Vellayani during 2021-2023. The objective of the study was evaluation of ready-mix pre-emergence and post-emergence herbicides for weed management and their effect on growth and yield of semi-dry rice in Onattukara region. The field experiment was carried out in farmer’s field at Onattukara Sandy Plains (AEU 3) during kharif season 2023. The experiment was laid out in RBD with eight treatments and three replications. The treatments comprised pre-emergence (PE) pendimethalin + pyrazosulfuron ethyl 787 g ha-1 followed by (fb) post-emergence (PoE) triafamone + ethoxysulfuron 60 g ha-1 (T1), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE penoxsulam + cyhalofop butyl 135 g ha-1 (T2), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE bispyribac sodium 25 g ha-1 (T3), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb mechanical weeding at 25 DAS (T4), PE pendimethalin 770 g ha-1 fb mechanical weeding at 25 DAS (T5), mechanical weeding twice at 15 and 30 DAS (T6), hand weeding twice at 15 and 30 DAS (T7), and weedy check (T8). Ready-mix formulations of pendimethalin + pyrazosulfuron ethyl, triafamone + ethoxysulfuron and penoxsulam + cyhalofop butyl were used in the study. Pre-emergence herbicides were applied on the next day after sowing and post emergence herbicides were applied at 25 DAS. Mechanical weeding was done with wheel hoe weeder. The short duration rice variety ‘Bhagya’ was used in the study. Weed management practices significantly influenced the growth parametres such as plant height, number of tillers per square metre, and dry matter per hill. In comparison to other weed management treatments, treatments (T1, T2, T3, and T4) that recieved PE pendimethalin + pyrazosulfuron ethyl had taller plants and more tillers per square metre at 20 DAS. PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) recorded significantly higher plant height (64, 92, and 106 cm), more number of tillers per square metre (486, 552, and 515) and dry matter production per hill (8.08, 14.47, and 17.70 g) at 40 DAS, 60 DAS and harvest. 98 Leaf area index (LAI) was higher in T1, T2, T3, and T4 at 20 DAS. Treatment T2 resulted in higher LAI at 40 DAS (3.27) and 60 DAS (6.23). Crop growth rate (CGR) observed in T2 during 20-40 DAS (18.20 g m-2 d-1) was higher and showed an increase during 40-60 DAS (21.29 g m-2 d-1). Relative growth rate (RGR) was higher in T2 during 20-40 DAS (0.057 g g-1 d-1) than T1, T3, T4, T5, and T6. During 40-60 DAS, RGR in T2 was comparable. Weed management practices significantly influenced the yield attributes of rice. Treatment T2 resulted in higher number of productive tillers per square metre (462), greater number of spikelets (120) and filled grains per panicle (108), heavier grains per panicle (3.09 g), and the lowest sterility percentage (10.40 %). The combination of PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in significant increase in grain yield (4960 kg ha-1), straw yield (6175 kg ha-1), and harvest index (0.45). Compared to treatment T7 (hand weeded twice at 15 DAS and 30 DAS) treatment T2 exhibited about a 40 per cent increase in grain yield. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. The major weed species observed in the experimental field were categorised in to grasses, sedges and broad leaf weeds. Oryza sativa f. spontanea, Isachne miliacea Roth ex Roem et Schult, Eleusine indica (L.) Gaertn, Echinochloa colona L., Sacciolepis interrupta (Wild). Stapf, and Paspalum distichum L. were the major grasses. Cyperus iria L., Cyperus difformis L., and Fimbristylis miliacea (L.) Vahl were the major sedges. Ludwigia perennis L., Melochia corchorifolia L., Marsilea quadrifolia L. and Monochoria vaginalis (Burm. f.) C. Presl ex Kunth were the major broad leaf weeds observed in the experimental field. Weed management practices significantly reduced the absolute density of weeds. The treatments T1, T2, T3, and T4 exhibited lower absolute densities of grasses, sedges, and broad leaf weeds at 20 DAS. Whereas, T2 resulted in lower absolute density at 40 99 DAS and 60 DAS. At 40 DAS, the relative densities of grasses (34.95%), sedges (33.73%), and broad-leaf weeds (31.21%) in T2 indicating a larger proportion of grasses in total weed population. Compared to other treatments, T2 significantly lowered weed dry weight at 40 DAS (14.68 g m-2) and 60 DAS (26.14 g m-2) which resulted in higher weed control efficiency of 82.83 %, and 80.77 % at 40 DAS and 60 DAS. The treatment T2 resulted in higher nitrogen (140 kg ha-1) uptake by crop at harvest and it was on par with T1. The phosphorus uptake was highest in T2 (34 kg ha 1). The higher potassium (118 kg ha-1) uptake was recorded in treatment T2 and was comparable with T1, T3 and T4. The treatment T2 recorded lower weed removal of N, P, and K at 40 DAS and 60 DAS. The post-experimental soil available NPK were also observed to be higher in T2. The soil enzyme activity was significantly influenced by weed management treatments. Among the treatments, T2 recorded higher dehydrogenase activity at 40 DAS and 60 DAS. Urease activity at 40 DAS and 60 DAS were higher in T2 and was comparable with T1 and T3. Considering the treatments, PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in highest gross income (₹ 204488 ha-1), net income (₹ 58943 ha-1) and Benefit: Cost ratio (1.41). It could be concluded from the study that, the pre-emergence application of ready-mix pendimethalin + pyrazosulfuron ethyl 787 g ha-1 at 0-3 DAS followed by post emergence application of ready-mix penoxsulam + cyhalofop butyl 135 g ha-1 at 25 DAS can be recommended as a cost-effective weed management practice for better weed control, higher yield and net income in semi-dry rice at Onattukara Sandy Plains.
Zinc fertifortification of rice (Oryza sativa L.) cultivars
(Department of Agronomy, College of Agriculture , Vellayani, 2021-10-10) Namitha Krishna; Jacob, D
An experiment entitled “Zinc fertifortification of rice (Oryza sativa L.) cultivars” was conducted during 2019-2021 at College of Agriculture, Vellayani. The main objective of the study was to enhance the grain Zn content of rice cultivars through Zn fertilization. The field experiment was carried out in farmer’s field at Southern Coastal Plain (AEU 1) during the kharif season 2020-21. The field experiment was laid out in Randomised Block Design (with two factors) and was replicated thrice. The treatment combinations included four medium duration rice varieties viz., Uma (V1), Pournami (V2), Gouri (V3), DRR Dhan 45 (V4) and four foliar Zn fertilization viz., without ZnSO4 (F1), ZnSO4 @ 0.1 per cent at maximum tillering (MT) and milk (M) stages (F2), ZnSO4 @ 0.5 per cent at MT and M stages (F3), ZnSO4 @ 1.0 per cent at MT and M stages (F4). The growth parameters such as plant height, number of tillers per hill and dry matter production at panicle initiation and harvest stages were significantly influenced by foliar Zn fertilization. ZnSO4 @ 1.0 per cent (F4) recorded taller plants (80.5 and 113 cm), higher tillers per hill (20.2 and 15.7 nos.) and higher dry matter production (12.0 and 28.9 g hill-1 ) at panicle initiation and harvest stages respectively, and were comparable with ZnSO4 @ 0.5 per cent (F3). Higher leaf area index 3.87 recorded at panicle initiation stage in ZnSO4 @ 1.0 per cent (F4) was comparable to ZnSO4 @ 0.5 per cent (F3). Higher spikelets per panicle (120 nos.) and filled grains per panicle (78.0 nos.) recorded in Uma (V1) were statistically similar to Pournami (V2). Sterility per cent (35.2) and thousand grain weight (25.6 g) recorded in Uma (V1) was higher and comparable to DRR Dhan 45 (V4). ZnSO4 @ 1.0 per cent (F4) recorded higher values for yield attributes such as productive tillers per square meter (459 nos.), grain weight per panicle (2.37 g), spikelets per panicle (119 nos.), filled grains per panicle (83.3 nos.), which were comparable to ZnSO4 @ 0.5 per cent (F3). Foliar fertilization with ZnSO4 @ 1.0 per cent (F4) produced higher grain 4.65 t ha-1 and straw 4.85 t ha-1 yield, and was comparable to ZnSO4 @ 0.5 per cent (F3) which recorded grain and straw yield of 4.62 and 4.81 t ha-1 respectively. The increase in grain and straw yield due to ZnSO4 @ 0.5 per cent (F3) were 12.1 to 11.1 per cent respectively over the control plot (without ZnSO4 ) (F1). Biofortified rice variety DRR Dhan 45 (V4) recorded significantly higher Zn content in rough rice (28.6 mg kg-1 ) and its milled fractions viz., brown rice (33.7 mg kg1 ), white rice (25.3 mg kg-1 ), rice husk (51.1 mg kg -1 ) and rice bran (97.7 mg kg-1 ). Significantly higher Zn content was recorded in boiled rice (16.6 mg kg-1 ) and decanted rice water (19.9 mg kg-1 ) of variety DRR Dhan 45 (V4). As a variety with high Zn content in rough rice and its milled fractions, Gouri (V3) was second only to DRR Dhan 45 (V4). Among non biofortified rice varieties, lower Zn content in rough rice (18.8 mg kg-1 ), brown rice (16.3 mg kg-1 ), white rice (12.2 mg kg-1 ), rice husk (24.7 mg kg -1 ) and rice bran (47.1 mg kg-1 ) was recorded in Uma (V1) and was comparable with Pournami (V2). Lower Zn content recorded in boiled rice (8.0 mg kg-1 ) and decanted rice water (9.6 mg kg-1 ) of variety Uma (V1) was comparable to Pournami (V2). Foliar fertilization with ZnSO4 @ 1.0 per cent (F4) could increase Zn content in rough rice (24.0 mg kg-1 ), brown rice (28.3 mg kg-1 ), white rice (21.2 mg kg-1 ), rice bran (82.0 mg kg-1 ), boiled rice (13.9 mg kg-1 ), decanted rice water (16.7 mg kg-1 ). However, it was comparable with ZnSO4 @ 0.5 per cent (F3) which recorded Zn content of 22.0, 26.0, 19.5, 75.3, 12.8 and 15.4 mg kg-1 in rough rice, brown rice, white rice, rice bran, boiled rice, and decanted rice water respectively. Zn content in rice husk (54.6 mg kg-1 ) was significantly increased by ZnSO4 @ 1.0 per cent (F4). NPK content of grain and straw was enhanced by ZnSO4 @ 1.0 per cent (F4) resulting in higher plant uptake of NPK, which was comparable with ZnSO4 @ 0.5 per cent (F3). Varieties DRR Dhan 45 (V4) and Uma (V1) resulted in Zn biofortification recovery efficiency (ZnBRE) of 3.26 and 1.39 per cent respectively. Significantly higher ZnBRE efficiency of 3.14 per cent was recorded in ZnSO4 @ 0.5 per cent (F3), ZnSO4 @ 1.0 per cent (F4) recorded ZnBRE of 1.99 per cent. Economic analysis revealed highest gross income (₹ 140474 ha-1 ), net income (₹ 46900 ha-1 ) and benefit: cost ratio (1.50) in treatment combination non biofortified variety Uma foliar fertilized with ZnSO4 @ 0.5 per cent (v1f3). Increasing the foliar fertilized ZnSO4 from 0.5 per cent (v1f3) to 1.0 per cent (v1f4) in variety Uma could bring about only negligible increase in gross income, net income and benefit: cost ratio by 0.5 per cent, 1.1 per cent and 0.3 per cent respectively. Biofortified variety DRR Dhan 45 foliar fertilized with ZnSO4 @ 0.5 per cent (v4f3) recorded gross income, net income and benefit: cost ratio of ₹ 135753 ha-1 , ₹ 42019 ha-1 and 1.45 respectively. Increasing foliar fertilization of ZnSO4 from 0.5 per cent to 1.0 per cent resulted in an increment in gross income, net income and benefit: cost ratio by 1.2 per cent, 3.5 per cent and 0.7 per cent respectively. The present study indicated that foliar fertilization with ZnSO4 @ 0.5 per cent at maximum tillering and milk stages as an economically viable option to significantly increase grain and straw yield of rice, and also to increase Zn content in rough rice and its milled fractions, resulting in increased Zn content in boiled rice and decanted rice water, irrespective of the rice variety.