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Open Access
Production potential of two fodder grasses under different management practices
(Department of Agronomy, College of Agriculture, Vellayani, 1986) Raghavan Pillai, G; KAU; Madhavan Nair, K P
Open Access
Phosphorus management in a rice based cropping system
(Department of Agronomy, College of Agriculture, Vellayani, 1989) Annamma, George; KAU; Sasidhar, V K
In order to standardize an appropriate phosphorus management practice in a rice based cropping system involving rice-rice-cowpea/sesamum, field experiments were carried out in the rice fields of the Instructional Farm, College of Agriculture, Vellayani from June 1984 to September 1986. The experiment was laid out in a randomized block design with three replications. There were eight treatments. The treatments comprised of (1) continuous phosphorus application to all the three crops in the system (2) phosphorus application to the first and second crops of rice (3) phosphorus application to the first crop of rice and third crop of cowpea/sesamum (4) phosphorus application to the first crop of rice only (5) phosphorus application to the second crop of rice and third crop of cowpea/sesamum (6) phosphorus application to the second crop of rice only (7) phosphorus application to the third crop of cowpea/sesamum only (8) control plot with no addition of phosphorus to any of the crops in the system. The salient findings of the experiment are as follows: Phosphorus application had no significant influence on grain and straw yield of first crop of rice. But available nitrogen, available and total phosphorus and available potassium of the soil were increased with phosphorus application. Direct, residual and cumulative effects of phosphorus had no significant influence on grain and straw yield of second crop of rice. Phosphorus uptake could not show any variation due to the different treatments. Available and total phosphorus content of the soil were highest under cumulative phosphorus treatment. All the growth and yield attributes of third crop of cowpea and sesamum were increased by the direct and cumulative effects of phosphorus. Grain yield of cowpea was significantly increased by the direct application of phosphorus. Eventhough not significant the highest sesamum yield was accorded by the direct and cumulative application of phosphorus. Phosphorus uptake in all the growth stages of the crop was highest in direct phosphorus plots. Available and total phosphorus content of the soil was highest in continuous phosphorus applied plots. There was no significant influence on grain and straw yield of first crop of rice after cowpea and sesamum in the direct, residual and cumulative effects of phosphorus. Residual phosphorus was sufficient to maintain the available nitrogen status of the soil. Available phosphorus of the soil was increased by the direct, cumulative and continuous application of phosphorus and total phosphorus by continuous application of phosphorus. Balance sheet of available phosphorus revealed that the soil phosphorus level almost maintained, where phosphorus was applied only to the third crop of cowpea or sesamum. The highest net return and benefit-cost ratio for the rice-rice-cowpea and rice-rice-sesamum system was obtained when phosphorus was applied only to the third crop in the rice fallow and the residual effect being utilized by the succeeding rice crops.
Open Access
Seed production in stylosanthes gracilis under varying levels of population density, nutrition, moisturiser regimes and cuttings
(Department of Agronomy, College of Agriculture, Vellayani, 1989) Balachandran Nair, G K; KAU; Sreedharan, C
An investigation was carried out during the period from July 1980 to March 1982 in the Instructional Farm, College of Agriculture, Vellayani to study the agronomic techniques required for maximum seed production in Brazilian lucerne (Stylosanthes gracilis). The following three separate field experiments were conducted and data collected and analysed. The first experiment entitled ‘influence of cultivars and plant population on seed production’ was laid out as a22 Factorial Experiment in R. B. D and replicated five times with the objective to find out the best cultivar of Stylosanthes gracilis for seed production along with the seed rate. The treatments consisted of combinations of two cultivars of Stylosanthes gracilis viz. Schofield and Cook, and two seed rates viz. 2.5 and 5 kg/ha. The second experiment entitled ‘nutritional requirements of Stylosanthes for seed production’ was laid out as a32 Factorial Experiment in R. B. D and replicated thrice with the treatment combinations of three levels of phosphorus viz.80, 120 and 160 kg P2 O5/ha and three levels of lime viz. no lime, 375 and 750 kg lime/ha. The objective was to assess the phosphorus and lime requirement of the crop for maximum seed yield. The third experiment entitled ‘Effect of moisture regimes and cuttings on seed production’ was conducted as a 32 Factorial Experiment in R.B. D and replicated thrice with treatment combinations of three irrigation schedules (IW/CPE ratios) viz. 0.50, 0.75 and 1.00 and three cutting schedules viz. no cutting, one cutting and two cutting. The objective was to investigate the efficiency of irrigation schedules and cuttings on seed yield. The results from the investigation revealed that the variety cook produced significantly higher seed yield of about 64 kg/ha as against 35 kg/ha obtained from the variety schofield. The seed rate of 5 kg/ha gave the higher seed yield of about 56 kg/ha as against the seed yield of about 43 kg/ha under the seed rate of 2.5 kg/ha. The seed yield attributing characters like setting percentage of seeds and number of seeds per plant were maximum for the variety cook. All the growth characters contributed to about 66 per cent of the variation in seed yield. The highest net return per hectare was obtained when the variety schofield was grown under a seed rate of 2.5 kg/ha. Application of phosphorus at 120 kg and lime at 375 kg per hectare gave maximum seed yield of about 80 kg/ha. It was also found that higher levels of phosphorus like 120 or 160 kg/ha helped to increase the setting percentage of seeds. The biometric characters such as spread of plants, number of branches and LAI were significantly influenced by the application of 120 kg phosphorus and 375 kg lime per hectare. The nutrients uptake was also enhanced by the application of phosphorus and lime at the above levels. The growth characters influenced the seed yield by 53 per cent. The economic optimum doses of phosphorus and lime for maximum seed yield were found to be 149 kg and 593 kg per hectare respectively. The highest gross and net returns were obtained from plots treated with phosphorus and lime at 120 kg and 375 kg per hectare respectively. Irrigating the crop at IW/CPE ratio 1.00 gave the maximum seed yield of 89 kg/ha. When the crop was left without cut it produced the highest seed yield of 92 kg/ha. The maximum setting percentage of seeds and leaf production were observed when the crop was irrigated at ratio 1.00 and without cut. The no cutting treatment gave maximum number of seeds per plant. The biometric charaters like height, spread, number of branches and length of branches were all found maximum in treatments where no cutting was given. Maximum water use efficiency for seed production was recorded by the lowest irrigation ratio of 0.50 and also when the crop was left without cut. About 46 per cent of the variation in seed yield was explained by the growth characters. Maximum net return per hectare was obtained when the crop was irrigated at IW/CPE ratio 1.00 and without cut.
Open Access
Influence of levels of nitrogen, methods of application and plant population on the performance of the high yielding rice variety sabari
(Department of Agronomy, College of Agriculture, Vellayani, 1989) Mohamed Kunju, U; KAU; Sadanandan, N
An investigation was undertaken to study the effect of different levels and methods of nitrogen application and different plant populations on the growth, yield and quality of the rice variety sabari in the southern Region of Kerala. The treatments consisted of four levels of nitrogen (40,80,120 and 160 kg/ha), two methods of application of nitrogen (application of the entire dose through soil and 75 per cent through soild plus 25 per cent through foliage) and three levels of spacing viz.10x10cm (100 hills/m2) 10x15 cm (67 hills /m2) and 10x 20 cm (50 hills m2). The experiment was laid out in split-plot design, replicated thrice and conducted for two years at the Instructional Farm, College of Agriculture, Vellayani. Growth characters like plant height, number of tillers per hill, leaf area index and dry matter production at different stages of growth increased with incremental doses of nitrogen. Closer planting resulted in smaller plants and higher number of tillers per unit area. The leaf area index was high in closer planting. Total dry matter production at harvest was more in 10x15 cm spacing. Foliar application of nitrogen (25 per cent) increased the total dry matter production at harvest. Increasing levels of nitrogen delayed flowering. Number of panicles per unit area, length of panicle, weight of panicle, number of spikelets per unit area filled grains per panicle and number of grains per unit area were increased due to incremental levels of nitrogen. Application of the second top dose of nitrogen through foliage produced more number of panicles. It also increased the weight of panicle, number of filled grains per panicle and number of filled grins per unit area. Test weight of grain was more at higher levels of nitrogen. Foliar application also increased the test weight of grain. Maximum yield of grain was recorded at 120 kg/N/ha which was on par with 160 kg N/ha. The average yields of grain at the 40,80,120 and 160 kg N levels were 3149, 3818, 4106 and 4027 kg/ha respectively. Foliar application of the second top dose of nitrogen was superior to soil application in increasing grain yield. Higher grain yield was obtained at 10x15 cm spacing. Quadratic response curve was found to be a suitable fit for nitrogen dose. The overall economic optimum level of nitrogen was 120 kg/ha. It was low (109 kg/ha) at closer spacing and high (124 kg N/ha) at wider spacing. Straw yield was increased with increasing levels of nitrogen application. Foliar application also increased the straw yield. Foliar application of nitrogen resulted in higher grain straw ratio while higher levels of nitrogen decreased the ratio. Increasing doses and foliar method of nitrogen application increased the nitrogen content of plants at flowering and of straw and grain at harvest. Protein content of grain was high at higher levels of nitrogen. It was also increased due to foliar application. The uptakes of nitrogen, phosphorus and potassium were more at higher levels of nitrogen and foliar application. This was not influenced by different spacings. Increasing levels of nitrogen application resulted in only a marginal increase in the residual available nitrogen status of the soil. Residual available phosphorus and potassium in the soil were not appreciably influenced by any of the treatments. Net income and benefit cost ratio were highest at 120 kg N/ha. Foliar application also increased the net income. Among the different spacings 10x15 cm spacing recorded the maximum net income. A combination of 120 kg N/ha of which 25 per cent applied through foliage at the panicle initiation stage with 10x15 cm spacing was found to be the most ideal for maximum benefit from the rice variety sabari under the agroecological situations of the southern Region of Kerala.
Open Access
Agronomic investigations on 'TARO' (Colocasia esculenta L.) variety - Thamarakannan
(Department of Agronomy, College of Agriculture, Vellayani, 1986) Mohan Kumar, C R; KAU; Sadanandan, N
In order to standardize the cultural and fertilizer requirement of two (Colocasia esculata) two separate field experiments were conducted during 1983-84 and 1984-85 at the College of Agriculture, Vellayani. The first experiment (Experiment A) with treatments consisting of two sources of planting material (side and mother corn) four spacing (60 x 30, 45 x 45, 60x 45, 60x60 cm) and five sources of mulching (Green leaf, Coconut coir/husk waste, Water hyacinth, black polythene and no mulch) was conducted in asplit plot design. The second experiment (Experiemnt B) was a 3 x 2 partially confounded factorial design with three levels each of nitrogen (40,80,120 kg ha-1), P2O5 (25, 50,75 kg ha-1), K2O (50, 100,150 kg ha-1) and two times of application (two split application of N and K and three split application of N and K) with two replication
Open Access
Production potential of cassava (Manlhot esculent a Grants) intercropped in coconut gardens
(Department of Agronomy, College of Agriculture, Vellayani, 1986) Ramakrishnan Nayar, T V; KAU; Sadanandan, N
Field experiments were conducted at the coconut Research Station. Balaramapuram during 1983-84 and 1984-85 to study the production potential of cassava varieties Sreevisakham and Malayan-4, intercropped in coconut gardens, as influenced by planting density, growth regulators and different levels of NPK fertilisers. The cassava hybrid Sreevisakham was superior to the popular cultlvar Maiayan-4 in nuirber of nodes plant 1, number of functional leaves plant™1, leaf area index, net assimilation rate, crop growth rates, dry matter production, utilisation index, tuber bulking rate and in fresh tuber yield. For intercropping one hectare of coconut garden in which coconuts are spaced at 7.5 x 7.5 m, cassava plant population of 8000 (spacing 90 x 90 cm) was found to be optimum to produce maximum fresh tuber yield* Cassava plants at higher planting density, were stunted in growth and produced poor quality tubers. The growth regulators cycocel and ethrel though decreased the plant height, could not Influence either the yield attributes or yield and quality of cassava tubers.
Open Access
Agrotechniques for soil conservation in taungya systems
(Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Gopinathan, R; KAU; Sreedharan, C
An experiment on 'Agrotechniques for soil conservation in taungya systems' was conducted at the Instructional Farm, College of Horticulture, Vellanikkara for a period of two years from May 1984 to April 1986. The objectives of the experiment were to asses the run-off, soil and nutrient losses as influenced by the important taungya practices and to evolve economically and ecologically viable agroforestry measures for soil conservation. Eucalyptus , the main tree component , was intercropped with the usually cultivated taungya crops of cassava and rice . The efficiency of cassava planting on ridges, grass farming and grass stripping was also investigated. There were seven treatments replicated thrice in RBD. Daily run-off and soil loss were quantified by installing multi-slot device consisting of 47 slots and brick masonry settling tank specifically designed for the project.
Open Access
Fertilizer management of minor tuber crops in coconut based cropping system
(Department of Agronomy, College of Agriculture, Vellayani, 1989) Pushpakumari, R; KAU; Sasidhar, V K
An investigation was carried out to evolve the fertilizer management practices of minor tuber crops in coconut based cropping systems during the years 1985-86 and 1986-87. This investigation was carried out as two experiments. In experiment I, screening of minor tuber crops under varying intensities of shade was done adopting a split plot design with 4 replications. In experiment II the fertilizer management of minor tuber crops in coconut based cropping system was studied. The experiment II was conducted in randomised block design with 3 replications. While experiment I was taken up at the Instructional Farm, College of Agriculture, Vellayani, experiment II was conducted at Coconut Research Station, Balaramapuram. Shade had significant influence on the length of vine/height of plant, LAI, NAR, CGR, dry matter production chlorophyll content of leaves, starch and protein content of tubers and yield of tuber of greater yam, lesser yam, tannia and elephant footyam. With increase in shade intensity, the yield declined proportionately in greater yam and elephant footyam reocrding highest yield under open condition. The tuber yield of lesser yam under open and 25 per cent shade levels were statistically on par, beyond which a drastic reduction in yield was observed with increase in shade intensity. Tannia recorded highest yields under 25 per cent shade, with an almost equal yield under 50 per cent shade. Fertilizer levels did not significantly influence the growth and yield characters of lesser yam, elephant footyam and tannia. But for greater yam there was significant increase in plant height in the first year and tuber yield in the second year with increase in fertilizer level. Greater yam responded linearly to fertilizer levels recording maximum yield with full recommended dose of fertilizer, although the variation was significant only in the second year. Lesser yam had maximum yield at medium fertilizer level and elephant footyam at lowest level, though not significant. The general performance of tannia was very poor. The economics worked out for the fertilizer management practices of greater yam, lesser yam, tannia and elephant footyam revealed that among the four crops tried, elephant footyam gave the maximum net profit followed by greater yam and lesser yam. However, tannia resulted in a loss.
Open Access
Cultural, manurial and water requirements for sweet potato (Iponoea batatas (L) Lam.)
(Department of Agronomy, College of Agriculture, Vellayani, 1989) Oommen, M; KAU; Sadanandan, N
Three field experiments were conducted in the wet lands and garden lands of Instructional farm of College of Agriculture, Vellayani to work out cultural, manurial and water requirements for sweet potato. The treatments in the first experiment – Nutritional requirements of sweet potato – consisted of three level of nitrogen (50, 70 and 100kg N/ha), three levels of phosphorus (25, 50 and 75kg P2O5/ha) and three levels of potassium (50, 75 and 100kg K2O/ha). The experiment was laid out in a 33 partially confounded factorial design with two replications. The second experiment – spacing cum depth of application of fertilizers – consisted of three spacing (40cm x 20cm, 60cm x 20cm and 80cm x 20cm) and three depths of application of fertilizers (10cm, 20cm and 30cm). The experiment was laid out in a 32 factorial design in RBD with four replications. The third experiment – Irrigation requirement – consisted of four levels of irrigation (IW/CPE ratios 0.25, 0.50, 0.75 and 1.00) and four levels of fertilizers (50:25:50, 75:50:75, 100:75:100 and 125:100:125 kg N,P and k/ha). The experiment was laid out in a split plot design with five replications. In the experiment to study the nutritional requirement of sweet potato growth attributes like length of vine, number of branches and leaf area index were maximum at higher levels of nitrogen and potassium. The highest values of tuber number, tuber weight, length of tuber and girth of tuber were obtained by the application of 75kg N, 50kg P2O5 and 100kg K2O/ha. Application of nitrogen, phosphorus and potassium at the rate of 75:50:100 kg/ha was found to be optimum for higher tuber yield. While nitrogen nutrition increased the protein content of tuber, potassium application enhanced the starch content. Highest levels of nitrogen, phosphorus and potassium increased the leaf, stem and tuber dry matter production and tuber bulking rate. Potassium only did influence the net assimilation rate. Crop growth rate was maximum at higher levels of nitrogen, phosphorus and potassium. The plant uptake of nitrogen, phosphorus and potassium was maximum at the highest level of these nutrients. The NPK combination of 75kg N, 50kg P2O5 and 100kg K2O/ha resulted in the maximum net return. Experiment on spacing cum depth of application of fertilizers revealed that wider spacing of 80cm x 20cm enhanced the growth characters such as length of vine, number of branches and LAI. Depth of application was not influential on this aspect. Yield attributes like tuber number, tuber weight and girth of tuber were higher at the spacing of 40cm x 20cm but length of tuber was maximum under wider spacing. Application of fertilizers at 20cm depth recorded maximum values for the aforesaid characters. Closer spacing of 40cm x 20cm and 20cm deep placement of fertilizers recorded higher tuber yield. Among the quality attributes protein content alone was influenced by wiser spacing, but protein and starch contents were increased when fertilizers were applied at 20cm depth. Wider spacing increased leaf and stem dry matter and CGR while closer spacing recorded higher tuber dry matter, tuber bulking rate and net assimilation rate. Depth of application of fertilizers did not influence the dry matter production. Plant uptake of nitrogen, phosphorus and potassium was increased by wider spacing and by the application of fertilizers at a depth of 20cm. A combination of 40cm x 20cm spacing and 20cm deep fertilizer placement resulted in maximum net return. Experiment on irrigation requirements divulged that highest IW/CPE ratio and higher fertilizer combinations recorded maximum length of vine and LAI, but number of branches was not influenced by them. Number of tubers, weight of tubers, length of tubers and girth of tubers were not influenced by irrigation, while levels of fertilizers increased the length of tubers. Tuber yield was higher at IW/CPE ratio of 0.75. Fertilizer combination of 100:75:100 kg of N, P and k/ha produced the maximum yield. Starch and protein contents were increased at higher levels of irrigation and fertilizer application. Total dry matter production and bulking rate increased upto an IW/CPE ratio of 0.75 and upto a fertilizer lever of 100:75:100 kg N, P and k/ha. Plant uptake of nitrogen, phosphorus and potassium at harvest was maximum at higher levels of irrigation and fertilizer application. Irrigating the field when the IW/CPE ratio becomes 0.75 and application of fertilizers at a ratio of 100:75:100 kg N, P and k/ha recorded maximum net returns.

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