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Open Access
Customized fertilizer and nutrient scheduling for okra (abelmoschus esculentus (L.) moench)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2016) Yansin, Luikham; KAU; Anitha, S
Multinutrient deficiencies in soil are common nowadays due to imbalanced use and extensive mining of nutrients, which have also led to the decline of soil and crop productivity over time. Customized fertilizers (CF), which are multinutrient carriers facilitating the supply of complete range of nutrients in right proportion for the crop grown in a particular soil, have come up as an alternative to tide over these problems. Scheduling of nutrients by split application promotes efficient utilization of nutrients in a need based manner and helps to reduce nutrient losses from the soil. An investigation entitled “customized fertilizer and nutrient scheduling for okra (Abelmoschus esculentus (L.) Moench)” was carried out at the Water Management Research Unit, Vellanikkara, Thrissur from May to September, 2015 with the objective of developing a customized fertilizer and studying its techno- economic feasibility and nutrient scheduling in okra. The investigation consisted of 12 treatments viz., FYM + 75% CF (2 splits at 30 days interval), FYM + 75% CF (4 splits at 15 days interval), FYM + 100% CF (2 splits at 30 days interval), FYM + 100% CF (4 splits at 15 days interval), FYM + 125% CF (2 splits at 30 days interval), FYM + 125% CF (4 splits at 15 days interval), FYM + soil test based NPK application (N & K as 2 splits at 30 days interval), FYM + soil test based NPK application (N & K as 4 splits at 15 days interval), FYM + NPK as per POP (N & K as 2 splits at 30 days interval), FYM + NPK as per POP (N & K as 4 splits at 15 days interval), FYM alone based on N recommendation of POP (2 splits at 30 days interval) and absolute control. Biometric observations were recorded and nutrient contents and uptake were estimated at 30 DAS, 60 DAS and 90 DAS. A customized fertilizer grade was developed based on the initial analysis of macro and micronutrient contents of soil and nutrient requirement of okra. Water soluble fertilizers and straight fertilizers were used for the preparation of CF. Based on the soil fertility rating and nutrient recommendation for okra, the actual nutrients needed for the experimental site was worked out in kg ha-1 as 59N: 9P: 34K: 16Mg: 1B. Based on this, CF grade 22.01N: 3.35 P: 12.68K: 5.97Mg: 0.37B was developed. The study revealed that application of 125 per cent CF either as two or four splits was equally effective and recorded the highest yield compared to lower doses of CF and other nutrient management practices. Application of 125 per cent CF resulted in a yield increase of 32.11 per cent, 35.16 per cent and 49.84 per cent compared to soil test based application, application of nutrients at recommended dose and application of FYM alone respectively. Application of 100 per cent CF recorded higher yield compared to nutrient application based on soil test based NPK and NPK as per POP. The yield increase in 125 per cent CF was due to the better development of growth and yield parameters and higher nutrient uptake including that of Mg and B in customized fertilizer doses. The lower doses of CF (75%) performed equally well as soil test based NPK and NPK as per POP with respect to yield. The combined application of fertilizers along with FYM gave better yield than application of FYM alone as a source of nutrients. Faster delivery of nutrients could be achieved through fertilizers since FYM alone could not meet the huge requirement of nutrients by okra. In this study, application of CF and other fertilizers in more splits did not show significant increase in yield of okra. Application of CF showed a positive effect on the soil fertility status except for nitrogen. The improvement in nutrient status could be attributed to application of optimum dose of CF along with FYM to maintain adequate supply of nutrients. The application of higher levels of CF was cost effective and economically beneficial due to higher yield despite increased cost of cultivation owing to higher cost of inputs. Nutrient application in lower splits was more economical due to reduced labour. The study indicated that application of multinutrient carriers such as customized fertilizers are a technologically and economically viable practice for increasing soil and crop productivity. The quantities of NPK required as CF are much lower than the POP recommendations, and therefore fertilizer doses can be reduced substantially.
Open Access
Fertigation and mulching in oriental pickling melon (Cucumis melo var. conomon (L.) Makino) under high density planting
(Department of Agronomy,Vellanikkara, 2016) Ashly, P; KAU; Joseph, P A
A field experiment was conducted to study the eficcts of 'Fertigation and mulching in oriental pickling melon {Cucumis melo vor.conomon (L.) Makino ) under high density planting and LDPF mulching in the summer rice fallow at the Agricultural Research Station (ARS) , Mannuthy from December 2014 to February 2015. High density planting of short duration less spreading high yielding variety of op melon at 33,333 plants per hectare was found to increase the yield of op melon more than double the yield at the recommended population of 10,000 plants per hectare. Under high density planting there is a proportionate increase in the demand of water and nutrients, which are crucial for the balanced growth, development and yield of the crop. The purpose of this experiment was to find out an optimum level of irrigation, fertilizer which will be supplied as drip fertigation for the highest yield and quality of fruits under polythene mulched condition. There were nine drip fertigation combinations with three levels of irrigation (75, 100 and 125 per cent Ep ) and 3 levels of fertilizers (200, 250 and 300 per cent of RDF), and one control which were laid out in Randomized Block Design with three replications. There was a significant increase in the characters like length of vine, number of leaves per vine, number of secondary branches per vine, leaf area index and shoot dry matter production at harvest with increase in irrigation levels from 75 per cent Ep to 125 percent Ep. At the same lime, other growth attributes such as number of primary branches per vine and days to fust male and female flower appearance didn't show any significant effect with various drip irrigation levels. Similarly, under high density planting and polythene mulching, the length of vine, number of leaves per vine, number of secondary branches per vine, LAI and shoot dry matter production at harvest increased linearly with increase in fertilizer levels from 200 per cent to 300 per cent of recommended dose. But increase in fertilizer level did not make any significant effect on the number of primary branches of OP melon. It remained constant around 2 in all levels of irrigation and fertilizer. The interaction between irrigation and fertilizer levels was not significant in any of the characters viz., length of vine, number of leaves per vine, number of primary and secondary branches per vine and LAI and shoot dry matter production at harvest. Per hectare yield of crc^ as well as various yield attributes like number of fruits per plant, average fruit weight, average volume of fruit and fruit yield per plant were not affected significantly by various irrigation levels. However, the average weight and volume of fruits increased slightly and non significantly with increase in irrigation levels from 75 per cent Ep to 125 per cent Ep. All other parameters like number of fruits per plant, yield of fruits per plant and fruit yield per ha recorded maximum value at 100 per cent Ep and the value declined gradually when irrigation level was increased to 125 percent Ep. Even though the weight and volume of individual fruits were maximum at 125 per cent Ep, the number of fruits per plant was less in this treatment, which ultimately resulted in a raluction in per ha yield of the crop. Number of fruits per plant, fruit yield per plajit and per hectare yield of fruit showed significant increase with increase in fertilizer level from 200 per cent to 250 per cent of recommended dose of fertilizer. But a further increase in fertilizer level affected the above characters negalively.So also, among the fertilizer levels, the average weight and volume of fruits were highest at 250 per cent RDF even though the effect was non- significant. The interaction between irrigation and fertilizer levels was not significant on the weight of fruits per plant and average weight and volume of fruits. But, there was significant elTect of interaction between irrigation and fertilizer levels on characters like ftuit yield per plant and per ha. Highest fruit yield per plant and highest per ha fruit yield were recorded at IiFi which was significantly superior to all the other combinations except I3F2,. So, there was positive interaction up to 100 per cent Ep and 250 per cent of recommended dose of fertilizer level when applied together as drip fertigation with LDPE mulching. Number of days taken for the appearance of flowers and the number of days taken for harvest did not show significant variation under various levels of drip fertigation. The interaction between irrigation and fertilizer levels was also non- significant on these characters. In general, days to first male flowering and female flowering were 21 and 26 respectively in drip fertigation treatments, while they were 25 and 29 respectively in control. Fruits were harvested 63 and 68 days after planting in drip fertigation treatments and control plots respectively. There was an increase in fruit dry weight with increase in irrigation levels from 75 per cent Ep to 100 per cent Ep and then it declined with further increase in irrigation level to 125 per cent Ep and the highest fruit dry matter production was recorded with 250 per cent of RDF compared to both 200 and 300 per cent of RDF. The interaction between irrigation and fertilizer levels also significantly influenced the fruit dry matter production. The maximum was observed at a combination of irrigation with 100 per cent EP and fertilizer with 250 per cent RDF. Both nitrogen and phosphorus content of leaves at 45 DAS increased significantly with increase in irrigation levels from 75 per cent to 125 per cent Ep under drip irrigation. But the increase in potassium content with increase in irrigation levels was non- significant. But the concentration of nitrogen, phosphorus and potassium in leaves of op melon increased significantly with increase in fertilizer levels from 200 per cent RDF to 300 per cent RDF. This shows the tendency of op melon to absorb and accumulate more and more NPK in their leaves with an increase in their availability in the root zone. The interaction between the tested irrigation and fertilizer levels did not show any significant effect on the content of primary nutrients in leaves of op melon at 45 DAS. Nitrogen content of shoot at harvest increased significantly with irrigation levels from 75 per cent Ep to 125 per cent Ep and fertilizer level from 200 per cent to 300 per cent of RDF. The fruit nitrogen level at harvest remained constant with slight variation, with the different levels of irrigation and fertilizers. At the same time, the interaction between any of the tested irrigation and fertilizer levels did not make any significant effect on shoot and fruit nitrogen content at harvest. Levels of irrigation significantly influenced the total N uptake by the crop at harvest. With increase in irrigation levels, N uptake increased significantly up to band then decreased, b and b were at par. The total nitrogen uptake by the crop at harvest increased with increase in fertilizer levels upto F2 and then decreased. F2 was significantly superior to F| and F3. The interaction between irrigation and fertilizer levels didn't make an\ significant effect on the character. Phosphorus content of shoot at harvest of op melon was found increasing significantly with increase in drip irrigation levels from 75 per cent Ep to 125 per cent Ep and fertilizer from Fi to F3 levels. At the same time, the fruit phosphorus content at harvest was not significantly affected by an increased application of phosphorus in soil.Fruit P content at harvest was not influenced by levels of irrigation and fertilizers. None of the combinations between irrigation and fertilizer levels showed significant superiority in increasing either shoot or fruit phosphorus content in OP melon. Levels of irrigation significantly influenced the P uptake by the crop. With increase in irrigation levels, P uptake increased up to b- But b and b were at par and significantly superior to b- With increase in fertilizer levels, the P uptake by the crop also increased up to F3. But F2 and F3 were at par and significantly superior to Fi. The Interaction between irrigation and fertilizer levels could not make any significant effect on P uptake by the crop. Irrigation and fertilizer levels significantly influenced the potassium content of shoot at harvest, but not the content of fruit. Significantly the highest potassium content in shoot was recorded at irrigation level of 125 per cent Ep and fertilizer level of 300 % RDFfFj). The fruit potassium content remained constant with different irrigation and fertilizer levels. Levels of irrigation significantly influenced the total K uptake by the crop. With increase in irrigation levels, K uptake increased significantly up to b (100 per cent Ep) and then decreased. Similarly, total K uptake also increased significantly upto 250 per cent RDF and then decreased. The interaction between irrigation ai^d fertilizer levels didn't show any significant influence on total K up lake. With increase in drip irrigation from 75 to 125 per cent Ep field water use efficiency decreased from 215.6 ( kg ha-mm ') to 145.8 ( kg ha-mm'') . Among the fertilizer levels, highest field water use efficiency was reported by 200 per cent RBF (181.9 kg ha-mm"') . However, the variation in FWUE among the fertilizer levels was not as significant as that observed in irrigation treatments. High level of irrigation in the control practice reduced FWUE in a significant way and was the lowest at 42.7 kg ha-mm"'. Soil chemical properties such as pH and Electrical Conductivity didn't show appreciable variation due to the various levels of irrigation and fertilizer. This indicates that chemical properties of soil are not likely to be influenced by short term management practices like irrigation and fertilizer application. In all the treatments and control, soil moisture content was the highest in the surface layer of 0-15 cm and the lowest in the bottom most layer of 30-45 cm. The decrease in soil moisture content from surface to the bottom most layer was gradual. In each layer, moisture content increased with increase in drip irrigation level from 75 % Ep to 125 % Ep. The moisture content in each layer was more in the control plot as it received more moisture through flood irrigation. In each layer the variation in moisture content was negligible within every level of drip irrigation due to the influence of varying levels of fertilizers. Keeping quality of the fruits was not affected by irrigation or fertilizer levels up to 45 days after harvest under high density planting with LDPE mulching. All the drip fertigation treatments were far superior to control on increasing the net profit per hectare and also the net income per rupee invested. In all the irrigation treatments F2 fertilizer level increased the net profit per hectare as well as net income per rupee invested in a significant way as the increase in fertilizer level above Ft had negative effect on crop yield. Among the treatment combinations I2F2 recorded the highest net return of Rs. 531581 per hectare followed by I3F2 of Rs 513651. Among the treatment combinations also I2F2 recorded the highest net income of Rs 2.06 per rupee invested followed by 1.95 by both I3F2 and I}F2. The study may be concluded by stating that for the most profitable production of op melon in the summer rice fallows of Kerala, high yielding less spreading varieties like Saunhagya should be planted at a high density of 33,333 plants per hectare and managed by drip fertigation at 1 GO per cent Ep and 250 per cent RDF with LDPE mulching. This has produced the highest net profit per hectare and net income per rupee invested.
Open Access
Characterization and management of weedy rice (Oryza sativa f spontanea)
(Department of Agronomy, College of Agriculture, vellayani, 2016) Anjali, K; KAU; Ameena, M
The study entitled ‘Characterization and management of weedy rice (Oryza sativa f spontanea)’ was carried out as four separate experiments conducted at COA, Vellayani and farmers’ fields of Nemom block during 2014-16. The main objectives of the study were morpho-physiological and agronomic characterization of weedy rice morphotypes of Kerala; formulation of a management strategy and assessment of crop weed interference under elevated carbon dioxide concentration. Experiment I. ‘Morpho-physiological and agronomic characterization of weedy rice morphotypes’ was conducted as pot culture laid out in completely randomized design with eight weedy rice morphotypes collected from major rice tracts of Kerala (Trivandrum, Kuttanad, Kole lands, Palakkad, Kozhikode and Ezhome). Morphological characterization of weedy rice morphotypes using morphometric descriptors and its comparison with cultivated varieties revealed that during initial stages most of the weedy rice morphotype possess similar morphological characteristics as the cultivated varieties. Physiological characterization of weedy rice morphotypes revealed no significant variation in chlorophyll content, total soluble protein and stomatal characteristics with cultivated rice varieties. However, root growth in terms of volume and dry weight was significantly higher for most of the morphotypes collected from Trivandrum, Kuttanad, Palakkad, and Ezhome. Earliness in 50% flowering was observed in all the weedy rice morphotypes compared to cultivated rice. Sterility of weedy rice morphotypes were significantly higher (17.77 to 32.79%) compared to cultivated rice varieties (9.23 to 12.85%). All the weedy rice morphotypes collected showed a prominence in awn length ranging from 2.37 to 9.23 cm. An average grain and straw yield of 4.89 and 16.14 g plant-1 and 1000 grain weight of 20.42 g was recorded by weedy rice morphotypes. Shattering percentage expressed as grain threshebility was significantly high for weedy rice morphotypes ranging from 29.73 to 46.32%. The seeds of weedy rice recorded wide variation in longevity ranging from 4.96 to 15 months which is an indication of variable seed dormancy. Experiment II. ‘Management of weedy rice by enhancing rice competitiveness’ was undertaken as micro plot study by raising cultivated rice and most common weedy rice morphotype and maintaining a standard weedy rice population of 7 plants m-2. To enhance rice competitiveness, three levels of seed rates viz., 100,120 and 140 kg ha-1 in combination with three types of priming techniques, i.e., without priming, hydropriming and hardening (2.5 % KCl) were included.Among the treatments, seed rate of 100 kg ha-1 along with hydropriming(T2) recorded significantly higher number of grains per panicle (120.02), grain yield (4.44 t ha-1) and straw yield (6.71 t ha-1) which was on par with T5 (120 kg ha-1 + hydropriming). Confirmatory trial at farmers’ field revealed that seed rates of 100 kg ha-1 or 120 kg ha-1 along with hydropriming (T2& T5) resulted in superior yield attributes inrice viz., number of grains per panicle, grain and straw yield ha-1.Weedy rice count m-2 and dry weight were significantly lower under these treatments. T2 (100 kg+ hydropriming) along with T5 (120 kg+ hydropriming) turned out to be the most economic treatment with a B:C ratio of 1.68 and 1.64 respectively. Experiment III. ‘Effect of elevated CO2 concentration on growth of rice and weedy rice’, was undertaken as pot study under elevated CO2 concentration of 500 ppm in Open Top Chamber (Chamber A) and in ambient conditions (Chamber B and open field). The most common morphotype of weedy rice and two cultivated rice varieties (Jyothi and Uma) were selected for the study. Significant variations in vegetative (no of tillers, leaf area index and leaf area duration) as well as yield attributes and yield (no. of grain panicle-1, grain yield plant-1) were observed under elevated CO2 levels in all these three systems. Higher grain yield per plant was recorded by weedy rice in Chamber A with an elevated CO2 level (1.73 times higher than open condition), followed by Chamber B (recorded 1.19 times more than open condition). However, the extent of response varied among the cultivars under varying atmospheric situations with Uma showing a greater percentage increase in grain yield (51.4% in Chamber A and 40% in Chamber B) followed by weedy rice (42.3% in Chamber A and 16% in Chamber B). The study revealed significant variation among the weedy rice morphotypes. Cultivated rice and weedy rice exhibited morphological similarity during initial stages of growth. Seed rate of 100 kg ha-1 with hydropriming can be recommended as the most effective and economic management strategy for weedy rice. The response of weedy rice to elevated CO2 was more compared to cultivated rice varieties.
Open Access
Fertigation for precision farming in tomato (Solanum Iycopersicum L.)
(Department of Agronomy, College of Agriculture, vellayani, 2016) Amala, J; KAU; Elizabeth, K Syriac
The investigation entitled “Fertigation for precision farming in tomato (Solanum lycopersicum L.)” was carried out at College of Agriculture, Vellayani during the period 2015-2016 to standardize a fertigation schedule for precision farming in tomato and to assess the impact of precision farming practices on growth and yield and also to work out the economics. The field experiment was conducted during the summer season of 2015 (February to June) in farmer’s field at Pirappancode, Thiruvananthapuram district. The experiment was laid out in split plot design with eight treatment combinations and two controls, with four replications. Four levels of nutrients (l1- 75 per cent RD of N and K, l2- 100 per cent RD of N and K, l3- 125 per cent RD of N and K, l4- 150 per cent RD of N and K) constituted the main plot treatments and two fertigation intervals (i1- fertigation once in four days, i2- fertigation once in eight days) constituted the sub plot treatments. The two control treatments were, control 1 (KAU ad hoc POP for precision farming) and Control 2 (KAU POP for conventional farming). The hybrid tomato Lakshmi grafted on wild brinjal was used for the study. Among different nutrient levels, l3 (125 per cent RD of N and K) recorded the highest DMP (219.42 g plant-1), number of fruits plant-1(33.67), fruit set percentage (62.77) , fruit yield (1.54 kg plant-1 and 42.36 t ha-1) and was significantly superior to other nutrient levels tested. Fertigation at four days interval (i1) recorded the highest LAI, DMP (224.21 g plant-1), number of fruits plant-1 (35.53), fruit set percentage (60.74) and fruit yield (1.61 kg plant-1 and 44.25 t ha-1) and was significantly superior to i2 (fertigation at eight days interval). Moisture studies indicated that both WUE and water productivity significantly varied with nutrient levels and fertigation intervals. The highest WUE (40.62 kg ha mm-1) and water productivity (5.26 kg ha mm-1) were observed at 125 per cent RD of N and K. Fertigation at four days interval (i1) registered significantly higher WUE and water productivity than i2. Application of 125 per cent RD of N and K (l3) recorded the highest root weight of 10.27 g and the highest root volume of 26.58 cm3 and was statistically on par with 150 and 100 per cent RD of N and K. The treatment i1 was significantly superior to i2 for all root characteristics. Uptake of N, P and K varied significantly with nutrient levels and fertigation intervals. The treatment l3 recorded the highest N, P and K uptake and it was statistically on par with l4. Fertigation at four days interval (i1) was significantly superior to i2, in nutrient uptake. Among different interactions, 125 per cent RD of N and K at 4 days interval (l3i1) registered the highest DMP (245.28 g plant-1) and was statistically on par with 150 per cent RD of N and K at four days interval (l4i1). Also, l3i1 recorded the highest fruit yield (1.92 kg plant-1 and 52.70 t ha-1) and number of pickings (7.33) and was significantly superior to other interactions studied. Economics of the study showed that l3i1 (125 per cent RD of N and K at four days interval) registered the highest net income of ₹ 6,61,515 ha-1 and B:C ratio of 2.69 and it was significantly superior to all other interactions. KAU ad hoc POP for precision farming (Control 1) was significantly superior to KAU POP for conventional farming (Control 2), for all growth attributes, yield attributes and yield. The treatment combination 125 per cent RD of N and K given as fertigation at four days interval (l3i1) was superior to control 1 and control 2 with respect to yield attributes, yield and economics. Based on the results of the present field investigation, it can be concluded that application of 125 per cent RD of N and K (93.75 kg N and 31.25 kg K ha-1) as urea and muriate of potash respectively, in 30 splits through fertigation at four days interval along with basal application of FYM @ 25 t ha-1 and P @ 40 kg ha-1 as rock phosphate is the best schedule for hybrid tomato under precision farming.
Open Access
Varietal suitability and crop geometry of baby corn (Zea mays L.) in coconut garden
(Department of Agronomy, College of Agriculture, vellayani, 2016) Dona Scaria; KAU; Rajasree, G
The experiment entitled “Varietal suitability and crop geometry of baby corn (Zea mays L.) in coconut garden” was undertaken at the Coconut Research Station, Balaramapuram, Thiruvananthapuram, during the summer season (March to May) and the Kharif season (August to October) of 2015. The main objectives of the study were to understand the feasibility of introducing baby corn as intercrop in coconut garden, to assess the effect of varieties and spacings on its growth and productivity and to work out the economics of cultivation. The field experiment was laid out in Randomised Block Design with 9 treatments replicated thrice. The treatments comprised of combinations of three varieties and three spacings. The three varieties were Rasi 4212 (V1), G 5414 (V2) and CO-6 (V3) and the three spacings were 30 cm x 20 cm (S1), 45 cm x 20 cm (S2) and 60 cm x 20 cm (S3). The variety G 5414 recorded significantly higher baby cob weight with husk of 47.01 g cob-1 and 35.74 g cob-1, cob yield with husk of 10.97 t ha-1 and 9.98 t ha-1 and marketable baby cob yield of 3.67 t ha-1 and 3.36 t ha-1 in summer and Kharif respectively. This variety took less number of days from tasseling to harvest (2.11) and recorded the highest net income of RS. 133698 ha-1 and RS. 116629 ha-1 and B:C ratio of 2.70 and 2.49 in summer and Kharif seasons respectively. The variety G 5414 was followed by CO-6 in producing higher baby cob yield with husk and marketable baby cob yield. The growth attributes viz., plant height, number of leaves and leaf area index (LAI) at 15, 30 and 45 days after emergence (DAE), dry matter content and light interception were significantly higher for the variety CO-6. Green Stover yield was significantly higher for CO-6 (19.39 t ha-1 and 17.86 t ha-1 in summer and Kharif respectively) followed by G 5414 (16.08 t ha-1 and 14.35 t ha-1 in summer and Kharif respectively). The study revealed that spacing significantly influenced the growth attributes viz., plant height, number of leaves and LAI. The row spacing of 45 cm x 20 cm recorded the highest baby cob yield with husk of 10.90 t ha-1 and 9.63 t ha-1, marketable baby cob yield of 3.49 t ha-1 and 3.24 t ha-1 along with the highest net income of RS. 125839 ha-1 and RS. 114287 ha-1 and B:C ratio of 2.69 and 2.55 in summer and Kharif respectively. Baby cob weight with husk was significantly higher at 45 cm x 20 cm and baby cob-baby com ratio was the most desirable at 30 cm x 20 cm in summer. In summer, the interaction of CO-6 at 45 cm x 20 cm recorded the highest baby cob weight with husk (56.25 g cob-1), marketable baby cob yield (4.21 t ha-1) and B:C ratio (3.16). Net income was the highest with G 5414 at 45 cm x 20 cm and was on a par with CO-6 at 45 cm x 20 cm. In Kharif, CO-6 at 45 cm x 20 cm resulted in the highest baby cob yield with husk (11.16 t ha-1), marketable baby cob yield (3.68 t ha-1), net income (RS.145237 ha-1) and B:C ratio (3.03). The variety G 5414 at 45 cm x 20 cm was on a par with the variety CO-6 at 45 cm x 20 cm with respect to baby cob yield with husk (9.91 t ha-1) and marketable baby cob yield (3.49 t ha-1). The study revealed that, among the varieties tested, the variety G 5414 was superior and among the spacings, 45 cm x 20 cm was significantly superior in both summer and Kharif seasons. The interaction effects revealed that the variety G 5414 at 45 cm x 20 cm and the variety CO-6 at 45 cm x 20 cm were equally superior in terms of yield and economics. In baby com cultivation, detasseling is an important operation which is labour intensive. The variety G 5414 exhibited 50 per cent silking prior to tasseling and hence the detasseling before first harvesting could be avoided. This variety had a better appearance and uniformity compared to CO-6. In general, the baby com yield was higher in summer season compared to Kharif season. To conclude, the result of the study indicated that baby corn can be profitably intercropped in coconut gardens in summer and Kharif seasons. The baby corn hybrid G 5414 at 45 cm x 20 cm spacing resulted in higher baby cob yield with husk, marketable baby cob yield, net income and B:C ratio during both seasons in southern Kerala. The maize variety CO-6 also performed well in coconut garden during both summer and Kharif seasons.
Open Access
Water and weed management for aerobic rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 2017) Akhil, T Thomas; KAU; Deepa Thomas
Aerobic rice culture is a technology to improve the water productivity in rice culture. Water and weed management are two important aspects of this promising technology. It is well established that yield reduction in rice happen if the soil moisture level falls below the field capacity. Unlike in flooded conditions,weeds pose greater problem in aerobic rice production.A field study was undertaken at Agronomic Research Station (ARS), Chalakudy from September 2016 to January 2017 for developing appropriate water and weed management strategies for aerobic rice. The treatments comprised of three levels of irrigation in the main plot (irrigation at 10 mm cumulative pan evaporation (CPE), 20 mm CPE and 30 mm CPE) and five weed management treatments in the subplot (pre emergent herbicide oxadiargyl followed by hand weeding, oxadiargyl followed by 2,4- D sodium salt, oxadiargyl followed by bispyribac sodium at 20 days after sowing (DAS), hand weeding at 20 and 40 DAS and an unweeded control). Depth of irrigation was 3 cmand the total water applied including effective rainfall amounted to 933 mm, 574 mm, 403 mm in I1, I2 and I3 respectively. Irrigation at 10 mm CPE recorded higher values for growth parameters like plant height and number of tillers per meter as well as yield and yield attributes.Higher root volume also was recorded in these plots .Relative leaf water content and chlorophyll content were higher under frequently irrigated plots (10 mm CPE) than less irrigated plots. Moisture stress lead to inhibition of leaf production and decline in leaf area in aerobic rice. Higher availability of moisture, reduced stress, better growth and yield attributes contributed to higher yield under irrigation at 10 mm CPE. Moisture stress caused reduction of 44 percent grain yield under irrigation at 30 mm CPE over irrigation at 10 mm CPE. Hand weeding at 20 and 40 DAS resulted in better growth, yield and yield attributing factors of aerobic rice. Oxadiargyl followed by bispyribac sodium at 20 DAS and oxadiargyl followed by hand weeding at 20 DAS were the next bettertreatments which were on par.Weed competition resulted in 64 percent reduction in grain yield. Oxadiargyl when applied pre-emergent waseffective in controlling the first flush of weeds in the field. All the treatment combinations with oxadiargyl recorded the lower weed dry matter production and weed density. As the crop advanced to flowering, hand weeding at 20 and 40 DAS resulted in lower weed dry matter production and weed density. Better growth and yield in this treatment suggested a long critical period of weed competition in aerobic rice. Irrigation at 30 mm CPE registered the highest water productivity of 0.96 kg m-3, but with severe yield loss. Among weed management treatments hand weeding at 20 and 40 DAS recorded the highest water productivity (1.13 kg m-3) and the lowest was from unweeded control (0.37 kg m-3). Irrigation at 10 mm CPE in combination with hand weeding at 20 and 40 DAS registered the highest growth and grain yield (2791 kg ha-1) and recorded water productivity of 0.88 kg m-3. However irrigation at 10 mm CPE in combination with oxadiargyl followed by bispyribac sodium at 20 DAS resulted in the highest net return (Rs 51477 per hectare) and B:C ratio (2.3).
Open Access
Productivity of spinach beet as influenced by varieties and nutrient doses
(Department of Agronomy, College of Agriculture, Vellayani, 2017) Vinod Alur; KAU; Sheeba Rebecca, Isaac
The investigation entitled “Productivity of spinach beet as influenced by varieties and nutrient doses” was carried out at College of Agriculture, Vellayani, Thiruvananthapuram to assess the suitability of five varieties of spinach beet under protected and open conditions, to standardize the nutrient doses and to work out the economics. The experiment was laid out in split plot design in the Instructional Farm, College of Agriculture Vellayani at 8.50 N latitude, 76.9 0 E longitude, under protected and open conditions as two separate experiments during August- November 2015 and 2016 respectively. The treatments included five varieties (V1: All Green; V2: Pusa Bharathi; V3: Punjab Green; V4: Indam Kolkatta; V5: Trendy) in main plots and three nutrient levels ( N1: 40:20:40 kg NPK ha-1; N2: 60:30:60 kg NPK ha-1; N3: 80:40:80 kg NPK ha-1) in sub plots with four replications. The soil belonged to the order oxisol. The results of the experiment under protected condition revealed that among the five varieties tested, Punjab Green was found superior in terms of the number of leaves, leaf area index (LAI) and yield. The maximum leaf yield recorded by Punjab Green was 4.78 kg m-2 followed by All Green (4.56 kg m-2). Plant height, total number of leaves plant-1 and LAI were significantly higher at N3 (80:40:80 kg ha-1)compared to the lower doses. The same NPK level recorded the highest yield of 4.70 kg m-2 which was significantly superior to the other levels. The interaction effects were significant with v1n3 recording maximum leaf yield (5.06 kg m-2) followed by v3n3 (5.01 kg m-2). Nutrient uptake (NPK), protein and Fe contents were the highest in Punjab Green which was significantly superior to the other varieties, while vitamin C was the highest in Pusa Bharathi. Spinach beet fertilized with 80:40:80 kg NPK ha-1 showed significantly higher values for NPK uptake, Ca content and vitamin C. Soil pH was found to increase with higher levels of nutrients and organic carbon content decreased from the initial values. Available NPK status in soil were found to increase with the increased NPK application. The var. Punjab Green showed maximum net returns ( 881.59from 10m2) and benefit-cost ratio (1.44) and among nutrient levels, nutrient dose of 80:40:80 kg NPK ha-1 was found to be the most economical (net returns from 10 m2 - 835.54, B:C ratio- 1.42). Taking into account the interaction effects, the varieties All Green and Punjab Green at 80:40:80 kg NPK ha-1 could be recommended for cultivation under protected conditions. In open field condition, the var.All Green recorded significantly taller plants with the highest number of leaves, LAI and leaf yield. Among the different nutrient levels, N3 (80:40:80 kg NPK ha-1) was found to be significantly superior in yield attributes and leaf yield in spinach beet. The interaction of Pusa Bharathi and 80: 40: 80 kg NPK ha-1 registered significantly higher yield (4.14 kg m-2) followed by All Green at 80 :40 : 80 kg NPK ha-1 (4.02kg m-2). Nutrient uptake, vitamin A, C, protein and Ca contents were significantly high in the var. All Green and inthe nutrient dose of 80 :40:80 kg NPK ha-1. Interaction effect of the above combination (v1n3) also recorded higher values for the plant nutrient contents. Available N, P and K contents in soil significantly increased with increase in NPK levels. Economic analysis revealed that the interaction v2n3 (Pusa Bharathi and 80 :40 : 80 kg NPK ha-1) was most profitable ( net returns 495.39 from 10 m-2 and B:C ratio 1.25) followed by v1n3( net returns 418.36 from 10 m-2 and B:C ratio 1.21). The variety Punjab Green and All Green were the most suitable varieties for cultivation in polyhouse while All Green and Pusa Bharathi could be recommended for cultivation in the open. The Ca, protein chlorophyll content and NPK uptake were the highest in Punjab Green and All Green in the polyhouse and open respectively. The NPK dose of 80:40:80 kg NPK ha-1was found to be the suitable nutrient dose under both conditions irrespective of the variety. Taking into account the economics of cultivation, the combinations, All Green + 80:40:80 kg NPK ha-1 was the most profitable in the polyhouse while Pusa Bharathi + 80:40:80 kg NPKha-1, for cultivation in the open.
Open Access
Microsite variations of okra [Abelmoschus esculentus (L.) Moench.] Under different weed management practices
(Department of Agronomy, College of Horticulture, Vellanikkara, 2017) Shamla, K; KAU; Sindhu, P V
Okra [Abelmoschus esculentus (L.) Moench.] is a warm season vegetable crop cultivated mainly for its immature fruits. Weed control is an expensive management practice in okra production which can influence productivity of both crop and soil. Weed management practices can modify the micro environment of crops, the extent depending on the method adopted, environmental conditions, and other management practices. The present study was taken up in the Department of Agronomy, College of Horticulture, Vellanikkara during March to June, 2016 to assess the effect of weed management practices on microsite variations and their consequent effect on growth and yield of okra. The treatments comprised of four different organic mulches (mango leaves, paddy straw, newspaper and coir fibre mat), mulching with black polythene sheet, hand weeding, application of pre emergence herbicide and an unweeded control treatment. Black polythene mulching positively influenced the yield and yield attributes of okra and resulted in greatest plant height and number of branches. Mulching with black polythene, hand weeding and herbicide treatment reduced the number of days to harvest. Higher number of harvests and number of fruits per plant were obtained with black polythene mulching. This treatment recorded a fruit yield of 14.58 t ha-1, followed by the treatments paddy straw mulching and newspaper mulching (11.16 and 11.01 t ha-1). Crop uptake of nutrients was higher under black polythene mulch and was lowest in unweeded control. Similarly, except for coir fibre mat mulching, all other treatments with mulching showed higher uptake of nutrients, and consequently, these plants showed higher relative chlorophyll content (SPAD units). Mulching also improved the soil nutrient status as compared to hand weeded, herbicide treated and weedy check plots. Available N and K were higher in mulched plots while available P content was more or less similar in all the plots. Considerable effect of weed management practices on soil microclimate was noticed. Black polythene sheet recorded higher soil temperature during the entire crop period. Soil temperature in the plots with organic mulches was lower than the plots without mulching. In general, the soil moisture content at different growth stages of the crop was higher in all the treatments with mulching as compared to treatments without mulching. Higher population of soil microflora was observed with mulching as compared to unmulched plots. Paddy straw improved soil bacterial and fungal populations both at flowering and harvesting, whereas, actinomycetes were higher under black polythene mulch. At flowering, total population of P - solubilsers, nitrogen fixers and antagonists were higher under mulching with paddy straw. At harvest higher microbial biomass carbon was found in black polythene mulched plots, followed by paddy straw. Higher weed control efficiency (more than 90 %) was observed with black polythene mulching throughout the crop period. Among different organic mulches, newspaper mulch recorded higher weed control efficiency followed by paddy straw mulch. Mulching with coir fibre mat failed to reduce weed growth. Mulching with paddy straw and newspaper recorded lower weed indices than hand weeding and pre emergence application of pendimethalin. The highest benefit:cost ratio of 3.02 was recorded for black polythene mulching. Newspaper mulching and pre emergence spray of pendimethalin were next with respect to B:C ratio. Different weed management practices significantly influenced the micro environment of the crop, and influenced the yield and yield parameters of okra as well as the soil quality. Use of either organic (newspaper or paddy straw) or inorganic (polythene) mulches is a better alternative to manual weeding or herbicidal application for effective weed management and for better B:C ratio in okra.
Open Access
Rhizosphere management for higher root production in ashwagandha (Withania somnifera L. Dunal)
(Deparment of Agronomy, College of Agriculture, Padannakkad, 2017) Ashiba, A; KAU; Anilkumar, A S
The investigation entitled, ―Rhizosphere management for higher root production in ashwagandha (Withania somnifera L. Dunal)‖ was carried out at the Instructional farm attached to the College of Agriculture, Padannakkad during 2015-17 to study the effect of integrated nutrient management practices and summer irrigation on growth promotion and root production in ashwagandha. The experiment was laid out in RBD with 14 treatments replicated twice. The treatments were T1 - HDP in trenches mulched with polythene and filled with enriched growing medium, T2 - T1 + Recommended dose of NPK, T3 - T1 + Liquid organic manures, T4 - T2 + azospirillum, T5 - T3 + azospirillum, T6 - T4 + B and Mg, T7 - T5 + B and Mg, T8 - T6 + Summer irrigation at 15 mm CPE, T9 - T7 + Summer irrigation at 15 mm CPE, T10 - T6 + Summer irrigation at 30 mm CPE, T11 - T7 + Summer irrigation at 30 mm CPE, T12 - HDP in trenches filled with enriched growing medium, T13 - NRP in trenches filled with enriched growing medium, T14 - Broadcasting in trenches filled with enriched growing medium. The results of the field experiment revealed that all growth parameters of ashwagandha were significantly influenced by treatment effects. In general, the treatment T6 was found superior in enhancing vegetative growth. However, the treatments did not exert any significant effect on primary, secondary and tertiary branches at any of the growth stages. The treatments had no significant effect on primary root number during early stages of growth (45 DAT and 60 DAT). The effect of treatments was evident from 75 DAT onwards. T10 at 75 DAT; T9 at 90 DAT; and T8 at 105 DAT and 120 DAT recorded higher primary root number. With respect to root characters, T8 recorded higher root number, T8 and T10 recorded the greatest root length, T11 the highest root spread, and T10 the highest root volume at the time of harvest. The treatment T10, recorded the highest fresh and dry root weight per plant and fresh and dry root production per hectare. The highest LAI and seed yield per plant and seed production per hectare were registered by T6. In general, relative leaf water content and leaf temperature were unaffected by treatment effects. Crude alkaloid content ranged from 6.5 % to 10.4 %. The highest crude alkaloid content of 10.54 % was registered by T7. Other biochemical parameters namely total sugar and total amino acid content were not at all influenced by treatment effects. Azospirillum population ranged from 11.5 x 105 to 64 x 105 per gram dry soil. The highest population of 64 x 105 per gram dry soil was registered by the treatments T8 and T5. Seasonal consumptive use and mean daily consumptive use ranged from 145.73 mm to 250.80 mm and 1.22 to 2.09 mm respectively and T14 registered the higher values. The highest crop water use efficiency of 474.78 g m-3 was recorded by T10. Field water use efficiency varied from 84.46 to 222.31 g m-3 and the highest value was recorded by T6. The treatment which recorded the highest value of field water use efficiency also registered the highest water productivity of 1313.47 g m-3. The highest nitrogen content was recorded by T6. T8, T9 and T10 registered higher contents of phosphorus, potassium and boron respectively. The treatment, T10 was found worthwhile for popularization with respect to higher fresh and dry root yield per plant and root production per hectare, dry matter production, crop water use efficiency, gross income, net income and BCR.

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