Browsing by Author "Jacob John"

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Allelopathic effect of trees grown in homesteads of Kerala on ginger (Zingber officinale Roscoe)
(Department of Agronomy, College of Agriculture, Vellayani, 2016) Eldhhose Abraham; Jacob John
Allelopathic effect of trees grown in homesteads of Kerala on turmeric (Curcuma longa Linn.)
(Department of agronomy, College of agriculture, Padannakkad, 2015) Sruthi Lakshmi, P G; Jacob John
Crop productivity and weed dynamics in rice based farming systems
(Department of Agronomy, College of Agriculture, Vellayani, 2017) Madankumar, M; Jacob John
Crop-tree inventory of the home gardens of Southern Kerala
(Kerala Agricultural University, 1999) Jacob John; Achuthan Nair, M
Effect of time of sowing and weed management on the performance of dry sown rainfed rice
(Department of Agronomy, College of Agriculture, Vellayani, 1993) Jacob John; Thomas Alexander, V
An experiment was conducted at the College of Agriculture, Vellayani during the first crop season of 1992 to study the effect of time of sowing and weed management on the performance of dry sown rainfed rice using Onam variety. Split plot experiment in randomised block design with time of sowing as major treatments and weed management as minor treatments was adopted and the treatments replicated thrice. May 16, May 23 and May 30 were the first, second the third dates of sowing respectively. The weed management treatments included combination of butachlor with 2, 4-D, butachlor with hand weeding, hand weeding twice 20 and 40 DAS, complete weed free and un weeded control. Sowing on May 23 resulted in greater plant height, panicle weight, grain and straw yield, nutrient uptake, grain protein and lesser uptake of phosphorus and potash by weeds when compared to May 16 and May 30. The second best sowing date was May 16. When compared to un weeded control, hand weeding twice, combination of butachlor with hand weeding and butchlor with 2, 4-D gave higher plant height, tiller number, productive tiller number, panicle weight, thousand grain weight, grain yield, straw yield, nutrient uptake and grain protein out of which hand weeding was the best. Hand weeding also resulted in the lowest weed population, weed dry weight, nutrient uptake by weeds, weed index and the highest weed control efficiency. Initially, butachlor alone was ineffective in reducing weed population and its dry weight. However, the combination of butachlor with 2,4-D and butachlor with hand weeding was effective in later stages. The combination of butachlor with hand weeding resulted in higher weed control efficiency than butachlor with 2,4-D. The rice grains contained no applied weedicide residues. Hand weeding, combination of butachlor with hand weeding and butachlor with 2,4-D resulted in greater profit and benefit – cost ratio than un weeded control. However, the highest profit was obtained with hand weeding twice.
Identifying resilient rice based cropping systems involving tuber crops for lowlands
(Department of agronomy, college of agriculture ,Vellayani, 2023-10-09) Anju, B Raj.; Jacob John
The study entitled “Identifying resilient rice based cropping systems involving tuber crops for lowlands” was conducted at Department of Agronomy, College of Agriculture, Vellayani during the period from 2019-2023. The major objectives of the study were to evaluate the performance, in terms of yield and economics, of different rice based cropping systems involving tuber crops in lowlands under different nutrient levels, to analyse weed dynamics, soil health and carbon dioxide emission, and to assess the residual effect on the succeeding virippu rice crop. It could be concluded that, among different rice based cropping systems involving tuber crops in lowlands, rice-rice-sweet potato (C2) performed better in terms of yield, economics and weed control. Grain yield of succeeding crop of rice, recorded with F2 and F1 were comparable. Thus it was concluded that FYM, N and P could be reduced by 25 per cent in rice based cropping systems. Rice-(cassava+bush cowpea)-daincha (C4) recorded significantly higher available nutrients, carbon fractions with less CO2 emission. Hence, rice-(cassava+bush cowpea)-daincha (C4) could be adjudged as the resilient rice based cropping system involving tuber crops in lowlands.
Indole acetic acid oxidase activity in brinjal as influenced by fertiliser treatments
(Department of Soil science and Agricultural chemistry, College of Horticulture, Vellanikkara, 1998) Rosamma Abraham; Jacob John
The present investigation was carried out in the College of Horticulture, Vellanikkara, during 1995-1997. The study was aimed to find out the effect of organic manu ring and chemical fertilisers on the levels of lAA and its influence on growth and yield of brinjal by monitoring the activity of indole acetic acid oxidase in plant leaves at different stages of plant growth. The experiment was laid out in randomised block design with 13 treatments and three replications. The treatments include combinations of different levels of organic manure and fertiliser, that is, zero, normal recommended dose and double recommended dose with an without foliar application of 150 ppm !AA and absolute control. IAA oxidase activity was found to increase with the age of the plant upto the tlowering stage and thereafter it was found to decrease. Application of treatment was found to influence the IAA oxidase activity only at the fruiting stage of the plant. Height, number of branches; flowers and fruits per plant and average fruit weight were not significantly influenced by the treatments. Howe~er fruit yield in brinjal was increased by the application of FYM, fertiliser and laa. Fruit yield was increased when IAA was applied along with FYM or fertiliser alone or in combination. Plant N content was found to decrease from vegetative to flowering phase and thereafter it was found to increase. But the application of different treatments could not enhance the plant N content significantly. But the P contents was influenced significantly due to treatments K content was not influenced due to treatments. Potassium content of the plant was found to decrease with advancing growth stages. However, K content of the plant was not found to vary significantly. Treatments in general, enhanced the Fe and Mn content of the plant and the relative content of Mn in tissues at all stages of growth remained considerably lower than that of Fe. Fe and Mn contents of the plant bad no influence on !AA oxidase activity in this experimental condition. Application of FYM, fertiliser and their combination with and without supplementary addition ofIAA permitted significant difference in the uptake ofN, P and K compared to that in control. Maximum uptake of N and P was recorded by the treatment which received IAA application along with the double dose of fertiliser and FYM.
Media and nutrient management for organic amaranth (Amaranthus tricolor L.) in terrace gardens
(Department of Agronomy, College of Agriculture, Padannakkad, 2014) Ramesh Kumar, C; Jacob John
Performance and allelopathic effect of sweet potato in double cropped lowlands
(Department of Agronomy, College of Agriculture, Vellayani, 2022-12-20) Arun Thazhath; Jacob John
A study titled “Performance and allelopathic effect of sweet potato in double cropped lowlands”was conducted at College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana during the period from April 2020 to November 2020 with the objectives of evaluating the performance of sweet potato varieties in summer rice fallow, assessing their allelopathic effects on weeds and examining the residual effect on succeeding virippu rice crop in double cropped lowland rice based cropping system. The study comprised three experiments. Experiment-I was a laboratory bioassay, to assess the allelopathic effect of leaf leachates different varieties of sweet potato on rice var.Uma, laid out in completely randomized design (factorial CRD), with three replications. The two factors involved in the experiment were leaf leachate of different varieties and various concentrations. There were a total of 24 (Leaf leachate of 8 varieties) x (3 concentrations viz. 1: 5, 1:10 and 1:15 w/v) treatment combinations and one control (tap water). The varieties selected were Sree Kanaka, Sree Varun, Sree Arun, Sree Nandini, Sree Bhadra, Bhu Sona, Bhu Krishna and Kanjanghad. The parameters recordedwere germination percentage, days required for 50 per cent germination, germination index, plumule length, radicle length, response index, pH of leachates and phenol and tannin content of leachates. Experiment-II was a field experiment conducted by raising sweet potato varieties in double cropped lowland during the summer. Randomized block design (RBD) was adopted for this experiment with three replications. The treatments were the eight sweet potato varieties and one fallow treatment as control. Experiment-III was a field experiment aimed at examining the residual effect of sweet potato crop by raising rice crop in the same plots where experiment-II was conducted. Thus, the treatments of this experiment were same as that of experiment-II. Germination percentage was not significantly affected by the leaf leachates of different sweet potato varieties or the leachate concentration. The highest germination index was recorded in Sree Arun (1.87) and lowest in Bhu Krishna (1.59). Plumule length was maximum in treatment Sree Bhadra (4.6 cm) and lowest for Bhu Sona (3.93 87 cm). Control showed significantly greater plumule length (5.08 cm) than treatments. Maximum radicle length was observed in Sree Bhadra (8.93 cm) which was on par with Sree Kanaka and Sree Nandini. With respect to concentration of the leachates, radicle length was the greatest in 1:15 (w/v) (8.73 cm) and least in 1:5 (W/V) (8.14 cm). pH of all the leaf leachates were lower when compared to the control. Phenol content was the highest in leaf leachates of Bhu Krishna (2.34, 2.19 and 1.96 mg 100g1 at 1:5, 1:10 and 1:15 concentration levels respectively) followed by Bhu Sona. The maximum tannin content was observed in leaf leachate of Bhu Sona (80.40, 71.70, 63.57 mg 100g-1 at 1:5, 1:10 and 1:15 concentration levels respectively). Grass weeds were the most prevalent in the field. Among grasses, population of Leptochloa chinensis and Echinochloa crus-galli significantly differed among the treatments. The population of different species of broad-leaved weeds and sedges did not differ significantly among treatments. In case of grasses, the highest weed count was seen in the control (210.67) which was on par with Sree Bhadra and Bhu Sona. The lowest weed dry weight was in Sree Arun (9.37 g m-2 ) which was on par with Kanjanghad, Bhu Krishna, Sree Nandini and Sree Varun. The highest weed control efficiency was observed in Sree Arun (45.97 %) which was on par with Bhu Krishna (45.19 %). At 20 DAP, the dry matter production (DMP) was comparable among the sweet potato varieties. At 40 DAP, the highest dry matter production was observed in Sree Varun (35.97 g/plant) which was on par with Bhu Krishna and Sree Arun. At 60 DAP, maximum DMP was seen in Bhu Krishna (46.85 g/plant) and was on par with Sree Varun and Kanjanghad. At harvest, Bhu Krishna had maximum DMP (52.09 g/plant) and was on par with Sree Varun (50.13 g/plant). Crop growth rate (CGR), during the period of 40 to 60 DAP alone, was significantly higher in Bhu Krishna (4.57 g m-2 day-1 ) and it was on par with Kanjanghad (4.49 g m-2 day-1 ) and Sree Varun (3.63 g m-2 day-1 ). Relative growth rate (RGR), during the period of 40 DAP to 60 DAP alone, was highest in Kanjanghad (14.06 x 10-3 g g-1 day-1 ) and it was on par with Bhu Krishna (13.28 14.06 x 10-3 g g-1 day-1 ) and Sree Nandini (11.21 14.06 x 10-3 g g-1 day-1 ). At 40 DAP, the SPAD value was the highest for Sree Varun (39.07) which was on par with all treatments, except Sree Bhadra and Sree Arun. At 60 DAP, SPAD value 88 was the highest in Sree Nandini (40.03) which was on par with Kanjanghad, Bhu Krishna and Sree Varun. Post-harvest soil analysis revealed the lowest soil pH in control (5.25), Bhu Krishna, Sree Varun and Sree Kanaka all of which were on par. The highest organic carbon content was noticed in Sree Arun (1.36 %) which was commensurate with Bhu Krishna, Sree Nandini and Sree Varun. The highest available nitrogen content was observed in Bhu Sona (215.12 kg ha-1 ) which was similar to Kanjanghad, Bhu Krishna, Sree Bhadra and Sree Nandini. The highest available potassium content was observed in Bhu Sona (85.17 kg ha-1 ) and it was on par with control plot, Sree Bhadra, Sree Nandini and Sree Kanaka. Highest gross income, net income and benefit:cost ratio were obtained from Kanjanghad which was on par with Bhu Krishna and Sree Varun. Highest rice grain yield was obtained in the crop that followed Kanjanghad (2103.17 kg ha-1 ) which was on par with that which followed Bhu Krishna and Sree Arun. There was no significant difference in straw yield between treatments. Hence, from the experiments it can be concluded that Bhu Sona and Bhu Krishna varieties exerted a greater inhibitory allelopathic effect on rice seedling growth compared to other varieties. Among the varieties, Sree Arun (upto 64 %) and Bhu Krishna (upto 61 %) suppressed weed growth more with higher weed control efficiency. Evaluation of sweet potato varieties in summer fallows of double cropped lowland revealed that Bhu Krishna, Kanjanghad and Sree Varun performed better with respect to yield attributes, yield and economics. In the virippu rice crop raised to assess residual effect, higher yield was obtained the crop which succeeded Bhu Krishna, while the lowest yield was observed in crop that followed Bhu Sona.
Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows
(Department of Agronomy, College of Agricultuture,Vellayanire , Vellayani, 2025-02-04) Hemand, J; Jacob John
A field experiment entitled “Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows” was conducted at Department of Agronomy, College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana, Thiruvananthapuram, Kerala, during 2022 to 2024. The main objective was evaluation of intercrops in paired row planted rice in summer fallows of double cropped lowland rice field, in terms of weed dynamics, biological efficiency and economics. The field experiment was conducted during summer season of 2023-24 at Integrated Farming System Research Station (IFSRS), Karamana, Thiruvananthapuram, Kerala, India. The field experiment was laid out in randomized complete block design with ten treatments and three replications. The treatments were T1: Paired row of rice + grain cowpea, T2: Paired row of rice + finger millet, T3: Paired row of rice + Foxtail millet, T4: Paired row of rice + proso millet, T5: Sole crop of paired row rice, T6: Sole crop of grain cowpea, T7: Sole crop of finger millet, T8: Sole crop of foxtail millet, T9: Sole crop of proso millet, T10: Fallow. The varieties used for the study for rice, grain cowpea, finger millet, foxtail millet and proso millet were Uma, Bhagyalekshmi, Co 15, Co (Te)7 and TNAU 202, respectively. FYM and fertilizers were applied as per the recommendations (KAU, 2024 and TNAU, 2024) to rice, grain cowpea and millets, respectively. The growth attributes of rice and intercrops were recorded at monthly intervals. The analyzed data revealed that growth attributes of rice were significantly influenced by treatments. Among the treatments, the higher number of tillers m-2, and leaf area index were in sole crop of paired row rice (T5). Among the yield attributes, rice recorded the highest number of productive tillers m-2, grain yield and straw yield in the sole crop treatment(T5). The analyzed data showed that T5 recorded 8 to 15 per cent yield increase over intercropping treatments. The highest harvest index (0.48) of rice was obtained when intercropped with finger millet (T2). Sole crop of grain cowpea (T6) recorded the highest growth attributes when compared to intercropped treatments. Among the yield and yield attributes, number of pods per plant (15.87), grain yield (4526 kg ha-1), haulm yield (4526 kg ha-1) and harvest index (0.43) were the highest in sole crop of grain cowpea (T6). Analyzed data revealed that the plant height and number of tillers of finger millet, foxtail millet and proso millet were significantly influenced by intercropping treatments. The highest mean plant height and number of tillers m-2 were recorded in their sole crops. The sole crop yield of finger millet, foxtail millet and proso millet were higher than their intercropping treatments. Grasses were the predominant weed flora in the field. Total weed count and weed dry weight were significantly influenced by treatments. At 15 DAS, weed smothering efficiency (WSE) was highest in T4 (44.94%), while at 30 DAS and at 45 DAS, the highest efficiency of 43.79 and 40.57 per cent, were recorded in T1. The results on nutrient removal by weeds showed that significantly lower N, P and K were removed by weeds in T1 (Paired row of rice + grain cowpea). Total NPK uptake of crops were also influenced by the treatments. Higher nutrient uptake of all crops was seen in their sole cropping treatments. In rice, P uptake was significantly influenced by the treatments. The results on soil data revealed that the dehydrogenase activity (150.89 μg TPF g-1 soil d-1) was the highest in T1.The available N and P was higher in T6 and available K was higher in T9. The LER value was greater than unity in all intercropping treatments. Among the intercropping treatments, the highest RCC was observed in T1. Product of RCC was greater than one in all treatments. Aggressivity values were found positive in rice and negative in intercrops. Results indicated that rice equivalent yield from all intercropping system was significantly higher than sole crop of rice except in intercropping with proso millet. Highest monetary advantage was obtained from T1. Higher BCR and net income was observed in T1 (Rice + grain cowpea). Results revealed that net income of T1 was 39.27% higher than T5. The study on the performance of various intercrops in paired row planted rice in lowland summer fallows revealed that paired row planted rice intercropped with grain cowpea can be adjudged as the best treatment in case of weed control, biological efficiency and had higher net income and BCR.
Performance of Maize (Zea mays L.) intercropping systems in lowlands
(Department of Agronomy, College of Agriculture ,Vellayani, 2024-02-26) Meera, L Raj; Jacob John
The study entitled “Performance of maize (Zea mays L.) intercropping systems in lowlands” was undertaken at the College of Agriculture, Vellayani during 2021-2023. The objective was to evaluate different maize based intercropping systems in the summer fallow of double cropped lowland rice field in terms of weed dynamics, biological efficiency and economics. The field experiment was carried out at the Integrated Farming System Research Station (IFSRS), KAU, Karamana from January to May 2023 in Randomized Block Design with 10 treatments and three replications. The treatments comprised of T1: maize + bush cowpea (1:2), T2: maize + green gram (1:2), T3: maize + black gram (1:2), T4: maize + fodder cowpea (1:2), T5: sole crop of maize, T6: sole crop of bush cowpea, T7: sole crop of green gram, T8: sole crop of black gram, T9: sole crop of fodder cowpea and T10: fallow. Maize (var. TNAU maize hybrid Co-6) was raised as main crop and bush cowpea (var. PGCP-6), green gram (var.TM 96-2), black gram (var. VBN-6) and fodder cowpea (var. Aiswarya) were raised as intercrops. Maize was raised as per the recommendations of TNAU (CPG, 2005) and the intercrops as per KAU Package of Practice Recommendations (KAU, 2016). The results revealed that intercropping had significant effect on the growth and yield of the main crop and intercrops. Growth attributes of maize viz. plant height, number of leaves per plant, leaf area per plant and leaf area index (LAI) showed significant variation with intercropping. The treatment T5 resulted in taller plants, highest number of leaves per plant, leaf area per plant and LAI and it was followed by T1. Seed weight per cob (63.02 g), grain yield (4566 kg ha-1) and stover yield (13122 kg ha-1) were also highest in T5, which was followed by T3. Growth and yield attributes of intercrops were significantly reduced under intercropping systems. Sole crop of bush cowpea (T6), green gram (T7) and black gram (T8) recorded greatest plant height, number of branches per plant, leaf area per plant and LAI. Yield attributes like number of pods per plant, grain yield and haulm yield were also higher in sole cropping system. The plant height, number of branches per plant, leaf area per plant, leaf area index, leaf stem ratio, green fodder yield and dry fodder yield were higher in the sole crop of fodder cowpea (T9). Intercropping with maize profoundly reduced the weed count, weed dry matter production (DMP) and NPK removal by weeds. The lowest weed count was recorded in T9 at 30 DAS. At 60 DAS, lowest weed count was recorded in T3 and T1. The highest weed count was recorded in T10, both at 30 and 60 DAS. Lowest weed DMP was recorded in T1, 30 and 60 DAS. The weed smothering efficiency of maize + bush cowpea system was the highest among the different intercrops at 30 and 60 DAS (41.46 % and 59.04 % respectively). The N removal by weeds was lowest in T1(1.15 kg ha-1), which was on par with T4 (1.54 kg ha-1) at 30 DAS. At 60 DAS the lowest N removal was recorded in T1 (5.58 kg ha-1). P removal by weeds was lowest in T1 (0.62 kg ha-1, 0.64 kg ha-1) which was on par with T3 (1.78 kg ha-1,1.85 kg ha-1) both 30 DAS and 60 DAS respectively. K removal by weeds was lowest in T1 at 30 DAS (0.92 kg ha-1) and 60 DAS (2.22 kg ha-1). All the crops recorded higher values of NPK uptake under sole cropping of main crop and intercrops. The dehydrogenase activity was the highest in the maize + bush cowpea (T1) (175.52 µg TPF g-1 soil d-1) system compared to the others. The highest amount of available N in the soil found after the experiment was in T8 (472.29 kg ha-1) which was on par with T7 (397.23 kg ha-1) and T9 (397.23 kg ha-1). The highest amount of available P was found in T9 (71.00 kg ha-1) while available K was higher in T8 (168.64 kg ha-1). Analysis of the competitive indices of the intercropping system revealed that the land equivalent ratio (LER), monetary advantage index (MAI) and maize equivalent yield (MEY) were highest in the maize + black gram system (T3). The highest relative crowding coefficient and positive aggressivity value of maize indicated the dominance and competitive nature of maize over intercrops. The maize + black gram (T3) intercropping system recorded the highest net income (₹ 102262 ha-1) and B:C ratio (2.15). From the present study, it is inferred that in summer fallows of double cropped lowland, maize + black gram (1:2) system was more suitable in terms of maize equivalent yield, land equivalent ratio, monetary advantage index, net income and benefit cost ratio. Based on weed dry matter production, weed smothering efficiency and nutrient removal by weeds, the maize + bush cowpea (1:2) system was the best.
Productivity enhancement of rice based cropping system with fodder crops
(Department of Agronomy, College of Agriculture, Vellayani, 2019) Bindya, B N; Jacob John
Productivity enhancement of rice based cropping system with pulses
(Department of Agronomy, College of Agriculture, Padannakkad, 2019) Adarsh, S; Jacob John
Relative efficiency of different weed management practices in dry sown rainfed rice
(Kerala Agricultural University, 1996) Jacob John; Thomas Alexander, V
Resilient rice based cropping systems for lowlands
(Department of Agronomy, College of Agriculture, Vellayani, 2024-04-01) Jince mary, M Joy.; Jacob John; Rajasree, G
The study entitled “Resilient rice based cropping systems for lowlands” was carried out at the Department of Agronomy, College of Agriculture, Vellayani during the period from 2019-2023. The major objectives of the study were to evaluate the performance, in terms of yield and economics, of different rice based cropping systems in lowlands, investigate their impact on weed dynamics, soil health and carbon dioxide emission, and assess the residual effect on the succeeding virippu rice crop. The investigation comprised two experiments viz. Experiment I: Performance of different rice based cropping systems in lowlands and their impact on the weed dynamics, soil health and carbon dioxide emission and Experiment II: Residual effect of rice based cropping systems on the succeeding virippu rice crop. The field experiments were carried out at the Integrated Farming System Research Station, Karamana, during 2019-2020 in randomized block design with eleven cropping systems [rice-fallow-fallow (T1), rice-rice-fallow (T2), rice-dhaincha – cowpea (T3), (rice + dhaincha)- rice – green gram (T4), rice – cassava – amaranthus (T5), ricecassava- cowpea (T6), rice – para grass- fodder cowpea (T7), rice- fodder cowpea – fodder maize (T8), rice- bhindi – culinary melon (T9), rice – bhindi – yard long bean (T10) and rice – rice – amaranthus (T11)], each replicated thrice. In treatment T4, dhaincha was used for brown manuring. It was raised as an intercrop by sowing seeds @ 20 kg ha,-1 two days after transplanting rice and was later incorporated by spraying 2, 4- D @ 1.0 kg ha -1 at 50 per cent flowering stage (45 DAS). The varieties used were, Uma (rice), dhaincha local (dhaincha), Anaswara (cowpea), CO-8 (green gram), Vellayani Hraswa (cassava), Arun (amaranthus), local (paragrass), CO-8 (fodder cowpea), African Tall (fodder maize), Salkeerthi (bhindi), KAU Vishal (culinary melon) and Vellayani Jyothika (yard long bean). During virippu, the highest yield of rice was in T9 (5016 kg ha-1) and the lowest in T1 (3463 kg ha-1). Fodder cowpea produced the highest yield among the crops grown during mundakan (24434 kg ha-1) and summer (26620 kg ha-1). The rice equivalent yield (REY) in mundakan and summer seasons differed significantly among the systems. The REY in mundakan was the highest in T10 (16761 kg ha-1) which was on par with T9 (16419 kg ha-1). The least REY in mundakan was obtained from T3 and T7 (486 kg ha-1). The highest REY in summer was obtained from T10 (7348 kg ha-1) followed by T11 (6532 kg ha-1) which were on par. Rice - bhindi - yard long bean sequence (T10) produced the lowest weed dry matter at 20 DAS (46.95 g m-2) and 40 DAS (33.15 g m-2). Highest weed dry matter at 20 DAS (75.80 g m-2) and 40 DAS (87.32g m-2) was recorded in T1 at the end of the crop cycle. Treatment T10 had the highest weed smothering efficiency (WSE) at 20 DAS (38.07 %) and 40 DAS (63.20%) at the end of the crop cycle. Data on influence of physical properties of soil at the end of crop cycle among the cropping systems revealed that, the greatest decrease (8.09%) in bulk density over the initial value was observed in T9 while T1 showed an increase in bulk density (1.37%). The highest increase in water holding capacity was observed in T4 (8.59%) while T1 showed a decrease in water holding capacity by 7.43% over the initial value by the end of the crop cycle. Soil pH did not vary significantly among the cropping sequences. Significantly higher organic C (1.94%, 1.86%), labile C (2310 mg kg-1, 1614 mg kg-1) and water-soluble C (33.69 mg kg-1 , 21.70 mg kg-1) at 0-15 cm and 15-30 cm respectively were recorded in T9 at the end of the crop cycle. Results on available nutrient status in soil at the end of crop cycle revealed that, the highest available nitrogen was noticed in T10 (342.87 kg ha -1) while available P and K did not show any significant variation among the cropping systems. Exchangeable Ca was the highest in T5 (215.08 mg kg-1) while exchangeable Mg and available Fe did not show any significant variation among the cropping systems. Available Zn was the highest in T6 (3.697 mg kg-1). At the end of crop cycle, T10 (rice - bhindi - yard long bean), T5 (rice - cassava- amaranthus) and T6 (rice- cassava – cowpea) recorded the highest urease (91.07 mg g- 1 h-1), acid phosphatase (31.16 μg g-1 h-1) and dehydrogenase activity (34.51, μg g-1 h-1) respectively. Perusal of data on total nutrient uptake by crops at the end of crop cycle divulged that among the cropping systems, the highest N uptake (234.70 kg ha-1) was in T8 while highest P (54.92 kg ha -1) and K uptake (244.90 kg ha-1) were noticed in T6. T5 recorded highest Ca (114.20 kg ha -1) and Fe uptake (12.60 kg ha-1) while T3 and T7 recorded highest Mg (81.89 kg ha -1) and Zn uptake (17.62 kg ha-1) respectively. Total nutrients recycled through crop residues at the end of crop cycle showed that, T4 recorded the highest nitrogen recycled (19.52 kg ha -1) while T6 recorded the highest P recycled (5.13 kg ha -1) and T10 recorded the highest K (17.04 kg ha -1) recycled. Highest Ca (8.61 kg ha -1) and Zn (1.55 kg ha -1) were recycled by T9 while T7 recorded the highest Mg recycled (8.16 kg ha -1) and T3 (1.81 kg ha -1) recorded the highest Fe recycled. Data on total nutrients removed by weeds by the end of crop cycle revealed that T7 recorded the least N removal (18.07 kg ha -1) while T8 recorded lowest P removal (6.70 kg ha -1) and T10 recorded lowest K (19.85 kg ha -1), Mg (2.24 kg ha -1) and Zn removal (0.015 kg ha -1). T8 recorded the lowest Ca removal (0.72 kg ha -1) and T3 recorded the lowest Fe removal (0.077 kg ha -1). The removal of all nutrients assessed was highest in T1. Results from CO2 emission study revealed that in mundakan, T5 (281 ppm) and T6 (283 ppm), with cassava exhibited lower CO2 emissions. T5 (25.93 ºC) recorded the least and T4 recorded the highest (32.24 ºC) soil temperatures in mundakan season. T7 and T8 recorded significantly higher soil temperatures (37.80 ºC) and the least (34.03 ºC) was noticed in T1 in summer season. The highest soil moisture was recorded in T4 (23.43%) which was on par with most of the treatments and the lowest value of soil moisture was noticed in T1 (15.92%) during mundakan. The highest rice equivalent yield (28.93 t ha-1), maximum gross returns (₹ 9,01,865 ha-1) and net returns (₹ 5,45,705 ha-1) were obtained in T10 (rice - bhindi - yard long bean). The B:C ratio was the highest for T9 (rice – bhindi - culinary melon) (2.64) followed by T10 (rice - bhindi - yard long bean) (2.53). Based on data of three years, the highest stability index was recorded in rice –cassava – cowpea (T6) (0.95) while rice - bhindi - yard long bean (T10) sequence had the lowest (0.42). The second experiment revealed that rice crop following rice – cassava – amaranthus (T5) was superior in terms of number of grains per panicle (113), grain yield (3934 kg ha-1) and straw yield (4311.67 kg ha -1). Significantly higher weed dry weight was recorded in T1 (48.25 g m-2) and the lowest in T5 (9.86 g m-2) at 20 DAS. At 40 DAT, significantly higher weed dry weight was noticed in T1 (96.12 g m-2) while the lowest was in T4 (23.66 g m-2). The treatment T8 recorded the highest weed smothering efficiency (80%) which was on par with T5 (79.63%) and T4 (77.05%) at 20 DAT. At 40 DAT, T4 recorded significantly higher weed smothering efficiency (74.33%). Significantly highest NUE was in the treatment T5 (8.62) and the lowest in T1 (5.74). Available NUE was highest in T5 (9.72) followed by T6 (9.24) which were on par, while T1 (7.06) showed lowest value of available NUE. It could be concluded that, among different rice based cropping systems in lowlands, rice – bhindi – yard long bean (T10) performed better in terms of yield, economics, weed dynamics and soil health. Cropping systems with cassava during the mundakan season had lower CO2 emissions. Rice crop succeeding rice – cassava – amaranthus (T5) was superior in terms of number of grains per panicle (113), grain yield (3934 kg ha -1) and straw yield (4311 kg ha -1), NUE (8.61) and available NUE (9.72).
Socio-economic characteristics of homestead farming in South Kerala
(Kerala Agricultural University, 1999) Jacob John; Achuthan Nair, M
Sturcture analysis and system dynamics of agroforestry home gardens of southern Kerala
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Jacob John; Achuthan Nair, M
A study entitled "Structure analysis and system dynamics of agroforestry home gardens of southern Kerala" was undertaken during the period from 1994 - 1997 in Thiruvananthapuram district of Kerala State. The study comprised of a detailed agroforestry systems inventory description survey of the home gardens in the district, investigations on the system dynamics of two home gardens of the district, laboratory experiments to assess the allelopathic tendencies of some commonly grown multipurpose tree species and linear programming to develop integrated homestead models. The results of the survey revealed that the size of an overwhelming number of holdings was small. The species diversity and average number of plants per home garden was considerably high. Tuber crops ranked first among the crops, followed by fruits, oilseeds, rubber, spices, vegetables, timber and fuel trees and fodder crops. The tree intensity was found to increase as the size of the holding decreased. The frequency of occurrence was highest for coconut, followed by jack, mango, moringa, guava, wild jack and tamarind and lowest for the nitrogen fixing trees. Differences between the agroecological zones of the district with respect to the predominance of crop categories and tree species were also observed. The home gardens presented a multi-tier canopy configuration. There was no specific planting pattern or arrangement. The system, as a whole, was found to be profitable. The two year long field investigation on the dynamics of home gardens revealed that the tree components contributed considerable amounts of nutrients by way of litterfall, stemflow and throughfall. Nutrient addition took place mainly through organic manures at both locations. Harvested biomass accounted for removal of large quantities of nutrients from the systems. Coconut accounted for maximum biomass production and nutrient removal at both sites. The physical, chemical and microbiological properties of the homestead soil were better than that of the control. The soil in the homestead had a lower bulk density, high water holding. capacity, porosity and moisture "Content. An enhanced soil organic carbon content, available N, P and K status were also observed in the home garden. The soil microbial population (bacteria, fungi, actinomycetes and phosphorus solubilizing bacteria) was comparatively higher in the home garden. Nutrient cycling, recycling of crop residues and addition of organic manures helped in improving and maintaining the soil physico-chemical and biological properties of the system in a sustainable manner. The presence of trees lowered the soil temperature in the homestead, whereas relative humidity was maintained at an optimum level when compared to open condition. The light intensities at the floor of all the trees studied were invariably less than that in the open. Both the home gardens were found to be profitable. The tree-crop-livestock integration was a special feature which increased income considerably. Allelopathic inhibition of germination and growth of rice was caused by leaf extracts of all the tree species. Germination of cowpea was inhibited by the leaf extracts of acacia, eucalyptus, casuarina, ailanthus, tamarind, portia and cashew. Growth of cowpea was suppressed by leaf extracts of all the tree species except jack. The powdered leaf litter of all the trees inhibited rice germination and growth. However, jack did not suppress radicle growth. Cowpea germination was inhibited by the powdered litter of all the trees except jack and mange. Cashew, casuarina and jack did not suppress plumule growth of cowpea. Radicle growth of cowpea was inhibited all tree species. The integrated model for the 0.50 ha home garden with 23 enterprises was found to generate a profit of Rs. 10354.21 with an investment of Rs. 3262.30. The coconut-based mixed fanning model developed for the 0.40 ha home garden with 35 enterprises provided a net profit of Rs. 32464.32 on investing Rs. 45000/-.