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Open Access
Economics of production and marketing of tuber crops in Palakkad district
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 1997) Sheena, P A; KAU; Thomas, E K
The present investigation on the economics of production and marketing of tuber crops viz. coleus, sweet potato and tapioca in Palakkad district was undertaken during the year 1994-95. The study focussed on estimation of cost and returns and marketing system. Data for the study was generated through a sample survey of farmers, village traders, wholesalers and retailers. Two stage sampling technique was adopted for the study, with panchayats selected purposively and sample farmers by random sampling method. The sample size for each crop was 50 making a total of 150 sample respondents. The results of the cost structure analysis revealed that the largest single item of expense was rental value of own land for coleus and tapioca and for sweet potato chemical fertilizer had the highest expense. Among the explicit cost items male labour accounted the highest share in coleus while rental value of own land and farmyard manure were the most important item in sweet potato and tapioca respectively. Cost A1, Cost A2, Cost B1, Cost B2, Cost C1 and Cost C2 per hectare was Rs.10101.74, Rs.13016.86, Rs.10101.74, Rs.17593.80, Rs.10743.99 and Rs.18236.05 respectively for coleus and Rs.8124.94, Rs.8124.94, Rs.13304.05, Rs.8852.50 and Rs.14031.61 respectively for tapioca and Rs.6733.13, Rs.6733.13, Rs.6733.13 and Rs.9079.94, Rs.7311.04 and Rs.9654.84 respectively for sweet potato. The average per hectare yield of coleus, sweet potato and tapioca were 9154 kg, 8801 kilogram and 7398.73 kilogram respectively. Benefit-cost ratio for coleus was Rs.2.27, Rs.1.76, Rs.2.27, Rs.1.30, Rs.2.13 and Rs.1.25 based on costs A1, A2, B1, B2, C1 and C2 where as the corresponding figures for sweet potato were Rs.1.74, Rs.1.74, Rs.1.74, Rs.1.29, Rs.1.60 and Rs.1.21 respectively. In the case of tapioca Benefit cost ratio was Rs.3.19, Rs.3.19, Rs.3.19, Rs.1.95, Rs.2.93 and Rs.1.85. The income measures in relation to different cost concepts, in coleus cultivation such as gross income, farm business income, family labour income, net income and farm investment income were Rs.22884.72, Rs.12782.98, Rs.5290.92, Rs.4648.67 and Rs.12140.73 respectively and Rs.11734.04, Rs.5000.91, Rs.2654.10, Rs.2076.20 and Rs.4423.00 respectively for sweet potato and Rs.25895.56, Rs.17770.62, Rs.12591.51, Rs.11863.95 and Rs.17043.06 respectively for coleus. Functional analysis was carried out using Cobb-douglas production function and the results revealed that for coleus fertilizer was found to be negative and significant. The production elasticity of labour was negative and insignificant. Farmyard manure and planting material were found to be insignificant. With regard to sweet potato labour was found to be negative and significant and the production elasticity of fertilizer was found to be negative though insignificant. Farmyard manure and planting material was found to be significantly influencing production. Regarding tapioca the production elasticity of labour and farmyard manure was found to be negative though insignificant. The high value of production elasticity of area indicated the dominance of this particular factor. Marginal value product of farmyard manure and planting material for coleus and sweet potato were greater than their factor cost ratio and was negative for labour and fertilizer. In the case of marketing of coleus and sweet potato more than 95 per cent of the produce was sold to wholesalers through commission agents. The producer’s share was only 34.53 per cent and 31.76 per cent of the consumers’ rupee for coleus and sweet potato respectively. The index of marketing efficiency was 0.53 for coleus and 0.47 for sweet potato. Regarding tapioca the tubers who performed the role of commission agent and from them produce is taken by mill owners of Salem and Dindigul. Since there is a product diversification the marketing of tapioca tubers was studied only upto the intermediary level.
Open Access
Design, fabrication and testing of a power operated jab type paddy dibbler
(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1997) Maji Krishnan, G; KAU; Jippu, Jacob
A power operated jab type paddy dibbler developed and tested at K.C.A.E.T, Tavanur is described. A cup feed type metering mechanism, discharged the seeds into the distribution wheel. Rotation of this wheel caused the transfer of seeds from the distribution wheel to the seed tubes. The to and fro motion of the plungers inside the five seed tubes closed and opened the port between the seed tran9fer tube and seed tube at predetermined intervals. A cam and follower arrangement fitted on the main shaft regulated the to and fro motion of the plungers. In operation, the rotation of the dibbler wheel caused the tip of seed tubes to make holes in the soil. At the time of penetration the plunger occupied a position farthest to the main shaft thus keeping the tip of seed tube closed. This prevented the entry of soil into the seed tube. After the seed tube has reached the maximum depth the plunger is moved up quickly transferring the seeds into the holes. The dibbler gave seed rates of 87.1, 74.6, 68.0, and 61.1 kg/ha at the speeds 0.788, 1.152, 1.530 and 1.778 km/h respectively in the field. It placed at an average 3-6 seeds in a hill at a depth of 4-4.2 cm. The number of seeds mechanically damaged was only 0.89 per cent and loss of viability due to mechanical damage was only 3.77 per cent. The average power required was 0.093 hp. Labour requirement was 60.68 man-h/ha. Cost of operation of this dibbler was Rs 86.0/h including the cost of power source. The jab type dibbler is convenient for use by both men and women.
Open Access
Biocontrol of water hyacinth using fungal pathogens
(Department of Plant Pathology, College of Agriculture, Vellayani, 1997) Susha Thara, S; KAU; Naseema, A
Detailed study was conducted on the host range of the already identified fungal pathogens of water hyacinth viz. Colletotrichum gloeosporioides, Fusarium eguiseti and F.pallidoroseum on thirty cultivated plants including vegetables, pulses and oil seeds, field crops, fruits and forest crops and ornamental plants and forty one common weed plants which are seen in and around water ways infested with water hyacinth. It was observed that C. gloeosporioides could infect amaranthus, bhindi, chilli, Euphorbia hirta, Hydrocotyl asiatica and Phyllanthus niruri. Of the thirty cultivated plants and forty one weed plants tested F. eguiseti was seen to be pathogenic to amaranthus, Amaranthus viridis, Commelina . bengalensis, C. jacobi and Monochoria vaginalis. F. pallidoroseum could produce symptoms on napier grass, Axonopus sp., boerhaavia diffusa, C.benghalensis, C.jacobi, Echinochloa colonum, Euphorbia hirta, Justicia diffusa, J.prostrata, M.vaginalis and Oldenlandia umbrellata and Scorpia dulcis. For the effective destruction of the weed, lxl011 spores per ml concentration of Q. gloeosporioides, E. eguiseti and F. pallidoroseum were found to be more effective than lxl09 and lxl010 spores per ml concentration. Cell free metabolites of the pathogenic fungi were found to produce symptoms on water hyacinth plant. Metabolite produced by E. pallidoroseum caused considerable damage than by E.equiseti and C. gloeosporioides. When pathogens were applied singly and in combination on water hyacinth it was observed that the combined application of F. pallidoroseum and F. equiseti followed by F. pallidoroseum alone gave maximum intensity of infection. Eventhough C. gloeospoirioides gave least intensity of infection it can be used as a co-pathogen with E. eguiseti. Metabolite of the pathogens individually and in combination when applied on healthy water hyacinth plants, maximum damage was caused by F.pallidoroseum alone and the combination of metabolite of three fungi viz. C. gloeosporioides,F equiseti and F. pallidoroseum. Least damage was caused by metabolite of C. gloeosporioides. An experiment was conducted to find out suitable carrier materials for the mass multiplication and storage of pathogen. It was observed that for C. gloeosporioides maximum sporulation was in water hyacinth leaf followed by guinea grass straw and rice bran. But the spore viability was maximum for rice straw, and on coir pith. Maximum infection was caused by fungus grown on guinea grass straw and rice straw. In the case of E. equiseti spore counts was higher in guinea grass straw followed by coir pith. The spore germination was maximum in rice bran and coir pith. Maximum infection was produced by the fungi on guinea grass straw, coir pith and waterhyacinth leaf. E. pallidoroseum produce maximum number of spores on rice bran followed by guinea grass straw. It was observed that the germination percentage of spores were maximum on coir pith. Out of the six carrier materials used the fungus produced maximum infection when grown on rice bran and guinea grass straw. In the study for testing the storage life of metabolities, it was observed that the efficiency to produce symptom was reduced on storage in the case of C. gloeosporioides and E. pallidoroseum whereas for E. eguiseti on storage the effeciency of the metabolite to cause damage increased. Metabolite stored on refrigerated condition performed poorly for all the three fungi. Different methods of application of the three fungi were tried. Of the five treatments, placement of bits and dusting the inoculum along with the carrier materials produced maximum infection. In the experiment conducted to characterize the toxin presented in the cell free metabolite of pathogenic fungi, observed the presence of Fusaric acid in the metabolite of Fusarium spp.
Open Access
Development of powertiller operated paddy reaper windrower
(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1997) Shiny, Lukose; KAU; Sivaswami, S
A vertical conveyor reaper-windrower suitable for mounting on KAMCO 9hp powertiller was developed Kerala for the first time. After considering the maneuvrability, weight distribution, field capacity and power transmission, the 1.6m width vertical reaper was selected for the KAMCO powertiller and was locally fabricated. The complete rotavator unit was dismantled and a newly designed power transmission unit was fitted on the KAMCO powertiller. The handle was kept at an ergonomically suitable height of 1m. A combination frame was developed inorder to accommodate both the engine and the reaper at the most appropriate location to achieve the static and dynamic balancing during field operation after the removal of rotavator. The centre of gravity of the engine at the new location was 50mm in front of the wheel axle and at a height of 180mm from its original position. Field evaluation of the reaper was carried out during November and December, 1996 at Tavanur. The front mounted reaper- windrower was evaluated to find out the optimum engine speed and forward speed to achieve better harvesting and windrowing pattern, maximum field capacity and field efficiency with less harvesting losses were found out. For the recommended engine speed of 1200 to 1400rpm at low first and low second gears a forward speed of 0.53 to O. 94m per sec. was obtained in the field. The actual cutting width was 1.5m. The maximum field efficiency of 85 per cent was obtained for first gear when the engine rpm was 1200. Actual field capacity for this speed was 0.224ha per hr. It was seen that for the recommended engine speed between 1200 to 1400rpm a normal forward speed of (.53 to 0. 94m/sec was obtained with an average actual field capacity of 0.25 ha/hr and an average total grain loss of 1.9 per cent in the field. Downward handle reaction for this recommended speeds varied between 9 to 14 kgf at the time releasing the clutch or using the accelarator. By the use of powertiller reaper a labour saving of 82.5 per cent was obtained. The owner would get a monitory benefit of Rs.1210/ha while the farmer hiring the reaper would get a saving of Rs.830/ha compared to manual harvesting. The initial invest of the owner would be paid back within 2 years if he could hire it out for 1000hrs per year. The total weight of the unit is 451kg which is 34kg less than the original weight the powertiller with rotavator unit. Its overall dimensions are L:279S x W: 1650 x h: 1510mm and the total cost is Rs.1,16,500.
Open Access
Distribution of extractable in soils of selected major land resource area of Kerala
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1997) Sathyanarayanan, R; KAU; Abdul, Hameed
The investigation was carried out to assess the total and available micronutrients in soils of selected major land resource areas (MLRAs) of' Kerala. The micronutrients investigated in the present study were iron, manganese, zinc, copper and boron. The study was intended to establish the pattern of the distribution of micronutrients both vertically and spatially in eight MLRAs viz, Palode, Vellayani, Trivandrum, Mannar, Kottarakkara, Thakazhy, Ramankary and D-Block soil series of Kerala. Three extractables viz DTPA, EDTA and ammonium acetate were used in the analysis. The available boron content in these soils was also determined by hot water extraction method. All the micronutrients showed great variation in their distribution in the various horizons of the profiles. The micronutrients content of the soils estimated were correlated with soil properties like pH, organic carbon, CEC and clay content. They were found to be positively and significantly correlated with organic carbon, CEC and clay content while it was significantly and negatively correlated with pH. The significant correlations revealed that the micronutrient availability in these soils were influenced greatly by the soil properties mentioned above. From the results obtained, it was observed that micronutrients like iron and manganese were well supplied in all the profiles studied. The micronutrients were found to decrease with depth except in Ramankary, D-Blockand Thakazhy series where it showed an irregular trend with depth due to the peculiar hydrologic and oxidation-reduction conditions existing in these soil series. The available and total micronutrients content in the surface soils from places around the profile sites did not show any significant variation among places. In almost all the samples very high iron content was recorded.
Open Access
Optimization of shade, nutrients and growth regulators for cut-flower production in anthurium
(Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 1997) Salvy, B R; KAU; Valsalakumari, P K
Experiments were conducted at the Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, during 1995-1997 to optimize the shade, nutrients and growth regulators for cut flower production in Anthurium andreanum var. 'Hawaiian Red'. The effects of three growth regulators, viz., GA, BA and Ethephon with two concentration each, 750 ppm and 1500 ppm, in combination with four nutrients, viz., 1 % fertilizer complex, Hoagland solution, Knop's solution and Ohio solution, were assessed at four levels of shade, viz., 80, 70, 60 and 50 per cent. Post harvest studies were also carried out with an objective to prolong the longevity of cut blooms, following different stage of harvest and giving different pulsing and hold- ing treatments. Results revealed that the different levels of shade and growth regulators significantly influenced all the morphological characters of the plant, viz., height, spread, number of leaves, leaf area, petiole length, number of branches and suckers. Plant height was significantly superior under 80 per cent shade (5.68 cm), 1 per cent fertilizer complex sprays (5.46 cm) and BA 750 ppm sprays (6.11 cm), were superior individually. The superior treatment combination was 70 per cent shade + Knop's solution + 750 ppm BA (7.60 cm). The maximum plant spread (EW - 20.13 cm and NS - 19.80 cm) was under 80 per cent shade. Eighty per cent shade + Ohio solution + 1500 ppm BA recorded the maximum EW spread (26 cm), while NS spread was maximum (28.70 cm) in the treatment combination involving 80 per cent shade + 1 per cent fertilizer complex + 750 ppm BA. The best values of growth parameters were recorded under 80 per cent shade and 750 ppm BA, viz., 14.03 and 14.02, respectively, for number of leaves (9.29 and 10.79 cm, respectively) for petiole length, leaf length (7.76 and 8.33 cm, respectively), leaf breadth (5.93 cm and 6.49 cm, respectively), index leaf area (50.75 cm- and 59.60 cm-, respectively). Total leaf area (423.25 cm? and 517.56 cm>, respectively) and LAI (0.43 and 0.51, respectively) were maximum under 70 per cent shade and BA 750 ppm. The superior combinations for these parameters were 80 per cent shade + Ohio solution + 750 ppm BA, for highest number of leaves (26.20); 80 per cent shade + Ohio solution + 1500 ppm BA for highest petiole length (14.00 cm); 60 per cent shade + Hoagland solution + 750 ppm BA for maximum leaf length (10.50 cm) and 60 per cent shade + 1 per cent fertilizer complex + 750 ppm BA for maximum leaf breadth (8.0 cm). The treatment combination involving 70 per cent shade + 1500 ppm BA with Hoagland solution was the best for maximum index leaf area (90.90 cm-) while same with 1 per cent fertilizer complex was the best for total leaf area (872.00 cm-) and LAl (0.89). Branching started only after 6 months from the commencement of the experiment. It was one month earlier under 80 per cent and 70 per cent shade levels. Significantly superior branching was observed under 80 per cent shade (2.29), fertilizer complex (2.13) and GA 750 ppm (2.37), individually. Treatment combination involving 80 per cent shade + 1 per cent fertilizer complex + 1500 ppm GA recorded the maximum branching (3.80). .' . Sucker production was the best under 80 per cent shade (1.35) and 750 ppm BA (1.35). Treatment combination involving 80 per cent shade + Ohio solution + 750 ppm BA produced the maximum number of suckers (2.5) per plant. Growth behaviour with respect to height, number of leaves, leaf area, number of suckers and branches showed a linear trend. The linear growth rate was consistent and positive under the treatment combination of 80 per cent shade + Ohio solution + 750 ppm BA. Dry matter production was significantly superior under higher shade intensity and lower concentration of BA. The dry weight ratio of shoot:root was the highest (2.15) under the treatment combination of 80 per cent shade + Knop's solu- tion + 750 ppm Ethephon. Leaf longevity was significantly highest (161 days) in the treatment combination, 70 per cent shade + 1 per cent fertilizer complex + 750 ppm BA. Stomatal distribution and size were not influenced significantly by the treatments. Leaf senescence, though was influenced significantly, no particular trend was observed. The aerial root production decreased significantly with decrease in shade intensity. Primary and secondary roots and root spread were the highest under 80 per cent shade and BA 1500 ppm. Maximum root length was observed under 60 per cent shade. Flowering with small stalkless flowers was first observed under 50 per cent shade with GA 750 ppm, at the age of 8 months. Inflorescence with normal size were produced at the age of 13 months, first under 80 per cent shade followed by 70 per cent, 60 per cent and 50 per cent. The time taken for various stages of flower development and the number of inflorescence produced per plant were not influenced significantly. Chlorophyll content in leaf was significantly influenced by shade levels. There was a decrease in chlorophyll content with decrease in intensity of shade. Eighty per cent shade and 1500 ppm Ethephon was superior with respect to the content of green pigments. The highest total chlorophyll content was observed in the treatment combination involving 60 per cent shade + Ohio solution + 750 ppm Ethephon (8.8 mg g -1 fresh weight). Anthocyanin content was not influenced by any of the treatments or combinations. The leaf nutrient content and uptake of nutrients was maximum under 80 per cent shade and BA 750 ppm, individually. Post harvest studies showed that the right stage of harvest of inflorescence was when 1/3 flowers were open on the spadix. Inflorescence harvested at this stage with medium to large size spathe lasted for a longer period (23.33 days). Among the pulsing treatments, BA 50 ppm for 12 hrs, recorded maximum vase life (20.00 days). Among the different holding solutions tried, 8-HQ 30 ppm, BA 20 ppm and Triadimefon 30 ppm recorded the optimum values of PL W, uptake of vase solution, change in pH and EC, and recorded late spathe blueing, late spadix necrosis and high gloss retention. Highest vase life period (27.00 days) was recorded in 8-HQ 30 ppm (25.00 days) and Triadimefon 30 ppm (25.00 days). Among the combinations tried, BA 20 ppm + Bavistin 0.1 per cent showed longest vase life (23.67 days). Maximum net profit per pot (Rs.204.60) was recorded by the treatment combination involving 80 per cent shade + Ohio solution + 750 ppm BA.
Open Access
Leaf litter dynamics in acacia and eucalyptus plantations
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1997) Moossa, P P; KAU; Venugopal, V K
An investigation entitled “Leaf litter dynamics in Acacia and Eucalyptus plantations” was undertaken to study the leaf litter production, litter decomposition and nutrient release characteristics, and impact of Eucalyptus and Acacia monoculture plantations on the soil physico-chemical and biological characteristics during 1994-97. One hectare each of Acacia auriculiformis, Eucalyptus tereticornis and a moist deciduous forest coming under the Kulathupuzha range of Kerala Forest Department were selected for the study. Field experiment were conducted to determine the leaf litter production and decomposition characteristics of plantation and natural forest. Leaf litter collected at monthly intervals showed that highest litter production was in Acacia (9.4 t ha-1 year-1) followed by natural forest (6.67 t ha-1 year-1) and Eucalyptus (4.68 t ha-1 yaer-1). Pattern of litter production was unimodal in Acacia and natural forest while in Eucalyptus it was bimodal. Chemical analysis of litter samples of plantations and natural forest revealed that with respect to nutrient content fresh and leaf litter of Acacia and Eucalyptus is superior to natural forest whereas litter quality in terms of water soluble components, polyphenols, lignin and cellulose were superior in natural forest. Annual dry matter loss of leaf litter by decomposition followed the order natural forest > Acacia > Eucalyptus. Nutrient release pattern of major and micro nutrients were also worked out for the leaf litter during the process of decomposition and natural forest litter recorded the highest mobility for all the nutrients on decomposition. Improvement in soil physico-chemical properties were noticed due to leaf litter decomposition in the monoculture plantation and natural forest. Biological activity in terms of earthworm and nematode under monoculture plantation was significantly lower than that of adjacent natural forest. Microbial content of soil below the litter bag during different months of decomposition were low in Eucalyptus and Acacia. Chemical analysis of the profile samples of various plantations revealed lower nutrient status in respect of major and micronutrients compared to natural forest. The physical properties of the soil also recorded as unfavourable change in the monoculture plantations as compared to the adjacent natural forest. Proximate anlysis of soil organic matter and humus characterization of the soil organic matter separated from various plantations indicated a low rate of humification and condensation under Eucalyptus. Low humic acid and fulvic acid content in humus and dominance of fulvic acid over humic acid was also noticed in Eucalyptus plantations. Functional group analysis of humic acid and fulvic acid showed that humic material separated from natural forest contained higher quantity of total acidity, contributed by COOH and phenolic group compared to plantation soils. UV, IR, DTA and TGA analysis of humic acid and fulvic acid separated from various plantations showed no variation with respect to natural forest. Allelopathic effect of fresh leaf and leaf litter extract of various plantations on the germination and growth of rice and cowpea followed the order Eucalyptus > Acacia > natural forest and as the concentration decreased from 1: 2 to 1: 10, the allelopathic inhibition also decreased significantly. Allelopathic effect of soil extract also followed the order Eucalyptus > Acacia > natural forest. Thus it can computed that though the leaf litter production and litter quality of monoculture plantations are comparable with that of natural forest, leaf litter decomposition and nutrient released were significantly lower than that of natural forest. Soil physico-chemical properties, soil fertility and biological activities were also adversely affected by monoculture plantations.
Open Access
Response of cucumber (Cucumis melo L.) to drip irrigation under varying levels of nitrogen and potash
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Lakshmi, S; KAU; Sasidhar, V K
Two field experiments and one observational trial were conducted in the Instructional Farm, College of Agriculture, Vellayani during 1992 and 1993 to study the effect of drip irrigation and application of N and K fertilizers on the growth and yield of cucumber. In the preliminary observation trial (Experiment I a) three levels of drip irrigation, (2, 3 and 4 I plant-1 day-1) four timings of irrigation (1, 2, 3 and 4 hours) and two number of drippers per plant (1 and 2 dripper plant-1) were evaluated and based on the results of this experiment, the number of drippers per plant and duration of drip irrigation was standardised. Experiment 1 b was conducted to standardise the method of application of fertilizers in Experiment 2 and 3 for which cucumber plants raised under different levels of drip irrigation (2, 3 and 4 I plant-1 day-1). This was conducted during April 1992. The results of these experiments indicated the duration for drip irrigation as 3 hours per day and one number of dripper per plant to be the best. The spread and depth of root system of cucumber plants raised under drip irrigation pointed out that the fertilizers as a ring around the base of the plant at a distance of 20 cm will be within the root zone of the plant. The experiments 2 and 3 were laid out in the field with three levels of drip irrigation (2, 3, and 4 I plant-1 day-1), three levels of nitrogen (35, 70 and 105 kg ha-1) with three levels of potassium (25, 50 and 75 kg ha-1) with three drip irrigation controls (2, 3 and 4 I plant-1 day-1) and farmer's practice. The yield of cucumber was highest at the drip irrigation level of 31 planr-1 day-1. Irrigation at this level favourably influenced the vegetative characters, yield attributes and yield. But root dry matter was not influenced by the different drip irrigation level while the root spread and root depth were highest at the drip irrigation level of 41 plant-1 day-1. When different levels of nitrogen applied were observed, the vegetative characters yield attributes and yield were found to be favourably influenced at 70 kg N ha-1. The root spread of cucumber was highest at the highest level of N applied (l05 kg ha-1). Potassium at 50 kg ha-1 produced the highest yield due to its favourable influence on the vegetative and yield characters. There was no influence of potassium on my of the root characters studied. The soil moisture status was highest up to 30 cm depth in all drip irrigated treatments while in pot watered plots, the soil moisture was higher in the lower layers below 30 cm. The field water use efficiency was highest at the drip irrigation level of 3 I plant-1 day-1, 70 kg nitrogen ha-1 and 50 kg potassium ha-1. The nitrogen, phosphorus and potassium uptake by the plants and fruits were highest at the drip irrigation level of 31 plant day I, 70 kg N ha-I and 50 kg K ha-I. The physical optium levels of drip irrigation was 31 plant -1 day -1, 93 kg N ha-1 and 65 kg K ha-1 in the first season. When another crop is repeatedly grown in the same field, the Nand K levels can be reduced to 75 kg ha-1 and 60. kg ha-1 but drip irrigation is required at the rate of 31 plant-1 day-1. This resulted in higher benefit cost ratio of 2.83 and internal rate of returns of 23%. The payback period of this project worked out to 1.13 years.
Open Access
Soil test crop response studies in cassava in laterite soils of Kerala
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Kumari Swadija, O; KAU; Sreedharan, C
An investigation was undertaken at the College of Agriculture, Vellayani to establish soil test crop response correlation for soil test based balanced fertilizer prescription for cassava var. M-4 in laterite soils of Kerala. The field investigation consisted of fertility gradient experiment, STCR experiment and technology verification trial. The fertility gradient experiment was conducted during April- May 1994 in the Instructional farm, Vellayani. The desired gradient in soil fertility was created in one and the same field by applying graded doses of N, P and K fertilizers and raising fodder maize var. African Tall. The STCR experiment was conducted in the same field during June '94-March '95 using the test crop, cassava var. M-4. The treatments consisted of factorial combinations of four levels of N (0, 50, 100 and 150 kg ha-1), three levels of P (0, 50 and 100 kg P2O5 ha-1) and five levels of K (0, 50, 100, 150 and 200 kg K20 ha-1) along with three levels of farmyard manure (0, 6.25 and 12.50 t ha-1) fitted in a response surface design. Using multiple regression model, the fertilizer adjustment equation for N at varying soil test values for available N for maximum tuber yield (t ha-1) of cassava in laterite soil was derived as FN = 136.6 - 0.2 SN where FN is fertilizer N (kg ha-1) and SN is soil available N (kg ha-1). The equation becomes FN = 136.6 - 0.2 SN - R for economic tuber production where R is the ratio of cost of one kg of fertilizer N to price of one kg of tuber. At varying soil test values for organic carbon% (OC) the above equations become FN = 226.13 - 378.13 OC for maximum tuber yield and FN = 226.13 - 378.13 OC - 1.25 R for economic tuber yield. The behaviour of fertilizer P and K was found to produce responses other than 'normal' and hence optimisation could not be done for fertilizer P and K for maximum and economic tuber yield at varying soil test values. The nutrient requirements of cassava var. M-4 were estimated to be 6.58, 2.37 and 6.28 kg N, P2O5 and K2O respectively to produce one ton of tuber. In the laterite soil, the efficiencies of contribution of nutrients from the soil for cassava were calculated as 40.17, 41. 3 3 and 48.60% N, P2O5 and K2O respectively. The fertilizer efficiencies were worked out as 54.38, 47 and 52.650% N, P2O5 and K2O respectively. The efficiencies of contribution of nutrients from farmyard manure were calculated as 78.24, 57.33 and 69.66%) N, P2O5 and K2O respectively. From the above basic data, fertilizer prescription equations for specific yield targets of cassava var. M-4 in the laterite soil were derived as given below. Without FYM FN = 12.10 T - 0.74 SN FP2O5 - 5.04 T - 2.02 SP FK2O = 11.93 T - 1.10 SK With FYM FN = 12.10 T - 0.74 SN - 1.44 ON F P2O5 - 5.04 T - 2.02 SP - 2.79 OP FK2O = 11.93 T - 1.10 SK - 1.58 OK where FN, F P2O5 and FK2O are fertilizer N, P2O5 and K2O respectively in kg ha-1, T is the target of tuber yield in t ha-1, SN, SP and SK are soil available N, P and K in kg ha-1 respectively and ON, OP and OK are quantities of N, P and K supplied through organic manure in kg ha-1 The technology verification trial was undertaken during June '96-March. '97 in the laterite soil in three farmers' fields in Thiruvananthapuram district and also in the Instructional Farm, Vellayani. The treatments consisted of Package of Practices recommendation for fertilizer, fertilizer recommendation by the Soil Testing Laboratory and fertilizer doses for the yield targets of 15, 20 and 25 t ha-1 along with a uniform dose of 6.25 t ha-1 of farmyard manure for all treatments. The fertilizer doses based on targeted yield equations recorded higher tuber yield and net income, benefit cost ratio and net returns per rupee invested over the fertilizer recommendation by the Soil Testing Laboratory and Package of Practices recommendation emphasising the need for site specific recommendation based on soil tests. The yield targets of 15 and 20 t ha-1 recorded more than cent per cent achievement and the yield target of 25 t ha-1 recorded about 90% achievement. Higher tuber yield, benefit cost ratio and net returns per rupee invested could be achieved for the yield target of 20 t ha-1. The fertilizer dose for the yield target of 15 t ha-1 recorded the highest returns per rupee invested on fertilizers. The study has revealed the superiority of fertilizer application based on targeted yield approach over the semi-quantitative approach employed in the soil testing laboratories and generalised state level Package of Practices recommendation for the crop. In this approach, the fertilizer dose can be adjusted in accordance with the specific objective and available resources of the farmer.

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