Browsing by Author "Sundaresan Nair, C"

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Effect of liming and application of mussoorie phosphate on the yield of green gram, var. Co-1, grown in the upland laterites of Kerala state
(Kerala Agricultural University, 1979) Sundaresan Nair, C; Aiyer, R S
Green gram variety Co-1 was grown with different forms and levels of phosphates superimposing a treatment of fully burnt lime at 500 kg/ha. The forms of phosphates compared were Mussoorie phosphate, single superphosphate and a complex fertilizer, factomphos (16:20). The results indicate that the response of green gram variety Co-1 is limited up to 15kg PgCyha and that between the forms, there is no significant difference. The use of Mussoorie phosphate entails a net saving of Rs. 50 per ha at application rates of 15 kg PjOs/ha. After harvest, if the tops are recycled three-fourths of the N applied will be returned to the soil. It has been shown that the pulse crop can give a net profit of Rs, 500 per ha under Kerala conditions.
Efficiency of rock phosphate in the acid rice soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1992) Visakha, L; Sundaresan Nair, C
Investigations were conducted to assess the suitability of Rajasthan rock phosphate for rice in two acid rice soils viz. Vellayani kayal soil and Moncompu soil respectively. The study also included a study on fractionation of the soil P collected at periodical intervals from these two locations for the different forms of P. The results are summarized below: 1. At both the locations a significant increase in height of plants, number of tillers, panicle length, thousand grain weight etc. was obtained by the application of phosphatic fertilizers over control. But between the different phosphatic forms no significant difference could not be observed. 2. In both the locations application of rock phosphate both Rajasthan rock phosphate as well as Mussoorie rock phosphate has been found to be as good as super phosphate in enhancing the yield of rice grain. 3. In both the locations the treatments with different forms of P increased the P content of grain and straw. This indicates that, the rock phosphate applied in acid soils while increasing the yield significantly increase the P content in plants also. In general, the treatments with phosphate fertilizers increase both the Ca and Mg content of grain and straw. The increase is much more marked in the case of calcium. 4. At both the locations the total P content of the soil is found to be significantly enhanced by the phosphatic fertilizer treatments. The highest total P content was recorded 20 days after transplanting and there is a progressive decrease in total P with time. 5. At Vellayani, super phosphate is found to be significantly superior to the other two rock phosphate in enhancing the available P status of the soil. But there is no significant difference between the two forms of rock phosphate in enhancing the available P. At Moncompu all the phosphatic treatments ie. super phosphate, mussoorie rock phosphate and Rajasthan rock phosphate were found to be equally good in enhancing the available P. The difference in response might be due to the difference in pH of the two soils. The highest available P content was recorded at 40th day at Vellayani and on 60th day at Moncompu.Thus there is variation in the period of submergence required for the attainment of peak value in available P in the two soils. Soil to soil variation is partly responsible for this. 6. Fe- P fraction of the soils treated with phosphatic fertilizers increase with period. Maximum Fe- P was recorded by super phosphate. However between the two rock phosphate there is no significant difference. Maximum Fe- P was recorded at 40th day of water logging. At Moncompu all the phosphatic fertilizer treatments significantly enhance the Fe- P content. All the phosphatic fertilizer forms significantly increase the Al- P fraction over control. But there is considerable variation in the behaviour at the two locations. The treatments significantly enhance the Al- P level at Moncompu than at Vellayani. The peak Al- P was recorded at 40th day at both the locations. There is progressive decrease in reductant soluble P and occluded P as the period progresses. The pattern was followed irrespective of soil types. The progressive decrease in reductant soluble P is accelerated by phosphatic fertilizer treatment in kayal and Moncompu soils. Same is the case with occluded P. The treatments with phosphatic fertilizers increase the Calcium P fractions in all the soils. Application of Mussoorie rock phosphate and Rajasthan rock phosphate as well as super phosphate enhance the Ca- P fraction. There is not much difference between the locations in enhancing the Ca-P fraction with respect to the treatments. Saloid fraction reach a peak value by 60 days of water logging. The results of the present study indicate that Rajasthan rock phosphate compares very well with super phosphate and Mussoorie rock phosphate under water logged situations. Its lower cost will substantially contribute towards reducing the input cost of phosphates under acid rice soil conditions. The studies on the pattern of dissolution give an indication that its solubilization and conversion to more available forms can be put to greater advantage in the growing of a rice crop by synchronizing the peak period of utilization of phosphate by the rice crop with the peak period of availability by shifting the basal application of rock phosphate by about 10 to 15 days perior to transplanting or sowing, in situations where such a practice is feasible.
Nutrient dynamics if the rice based cropping systems
(Department of soil Science and Agricultural Chemistry, College of agriculture, Vellayani, 1989) Sundaresan Nair, C; Subromonia Aiyer, R
Nutrient dynamics in the rice based cropping systems
(Division of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1989) Sundaresan Nair, C; Subramonia Aiyer, R
The experiment consisting of five cropping sequences viz. rice - rice – rice (A1), sweet potato – rice – rice (A2) cowpea – rice – rice (A3) daincha – rice – rice (A4) and fallow – rice – rice (A5) and six treatments with varying doses of N P and K were conducted to study the performance of the sequences in relation to the nutrients required for optimising the out put from the sequences. The field experiment was laid out at R.R.S., Pattambi in 1980 – 81 and the experiment was conducted for two consecutive years ie. For six seasons. The experiment was started with the summer crop of 1981, namely summer rice (Triveni), sweet potato, cowpea, daincha and a summer fallow wherein the land was ploughed twice and left as such without any crops. The component crops were raised with five treatment variations modified from the recommended doses for each crop. The biometric observations for the summer crops, virippu and mundakan crops were recorded. The indications were that treatments have a significant effect on summer crops virippu and mundakan rice crops of 1981 and 1982. The yield shows that both treatments and sequences have a significant effect. The sequence daincha – rice – rice and the cowpea – rice – rice sequence gave the highest yield. The chemical analyses of plant parts of the summer crops, virippu and mundakan rice crops of both 1981 and 1982 show that the treatments have no effect on the NPK content. The soil study shows that the cropping sequences have a significant effect on soil pH. A pH decrease was noticed in all the sequences, the highest decrease being in the rice – rice – rice sequence. The organic carbon level of the soil is also affected due to the cropping sequence. The rice – rice – rice sequence shows a maximum decrease in organic carbon level and the daincha – rice – rice – rice shows a gain in organic carbon level of the soil. The total nitrogen of the soil shows a decrease in all the sequences and maximum decrease was noticed in sweet potato – rice – rice sequence. The available nitrogen level also was influence both by the sequences and treatments. A decrease in available nitrogen was noted to be a maximum in the rice – rice – rice sequence. The total P and available P levels show an increase in all the sequences and were high in daincha – rice – rice and cowpea – rice – rice sequences. The treatments also have a significant effect in maintain the P level in soils. The total K status of the soil as well as the exchangeable status of K shows a decrease after two year of cropping. The nutrient uptake studies reveal that the maximum NPK uptake takes place in the sequences sweet potato – rice – rice followed by rice – rice – rice and cowpea- rice – rice – rice followed by rice – rice – rice and cowpea - rice – rice. The balance sheet of nutrients reveals that nitrogen and available phosphorus in all sequences show a decrease and increases with decrease in fertilizer levels. The balance sheet of K shows that the soil maintains K levels. The sequence daincha – rice – rice is the best in maintaining a high K status in the soil. An analysis of the economics of cropping sequences reveal that the sequence sweet potato – rice – rice with full recommended dose of fertilizers gave the highest net return, which was followed by Cowpea in – rice – rice and rice – rice – rice. From nutrient balance studies, yield and economic analysis it is clear that any attempt in reducing the quantity of fertilizer for the component crops of the sequences affects the yield, besides deleteriously affecting the fertility of the soils. Any decrease in the fertilizer doses in the sequences will not be economical. With a long range view of enhancing crop output from cropping sequences and maintaining soil fertility, it becomes necessary to enhance and maintain higher fertility levels.
Nutrient management for banana musa (AB Group) Njalipoovan in Onattukara soils
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2003) Indira, M; Sundaresan Nair, C
Banana cv. Njalipoovan is a popular variety cultivated in homesteads of Kerala. The nutritional requirement of the cultivar has not yet been worked out. Field experiments were conducted at Onattukara Regional Agricultural Research Station, Kayamkulam in Alappuzha district during 1998-99 and 1999-00 to formulate an effective nutrient management schedule for the cultivar in Onattukara soil. In addition to this a soil column study was undertaken separately to assess the leaching losses of nutrients in the soil and retention of applied nutrients at different depths. Three levels each of nitrogen at 100, 200 and 300 g plant", phosphorus at 100, 200 and 300 g plant! and potassium at 200, 400 and 600 g planr ! apart from nopoko (control) in each block were tested in confounded 33 factorial, confounding NPK in replication I and NP2K in replication H. Application of nitrogen at 300 g plant"! increased the growth attributes like height of the plant, girth of the pseudo stem, total number of leaves and number of functional leaves. Nitrogen supply at higher rates reduced the total duration of the crop, increased the LAI and leaf emergence rate, dry matter accumulation in leaves, pseudostem, rhizome 2 and bunch. Yield attributes and bunch yield increased significantly upto 300 g N planr l. The quality of the fruit was favoured by the application of higher rates of nitrogen. N supplementation at higher rates was beneficial for the uptake of N, P, K, Ca and Mg and micronutrients such as Mn, Zn and Cu. It also enhanced the available N, P, K, Ca and Mg in soil. Supply of phosphorus at 200 g plant"! increased the above growth attributes at most of the stages. LAI in the early stages of growth was favoured by P supply at high rate. Phosphorus application at 300 g plane I favoured dry matter accumulation in leaves, pseudostem, rhizome and bunch. Yield attributes and yield were high by applying phosphorus at 200 g planr ' Fruit quality was not affected by the application of P. Higher rate of P 20 5 enhanced the uptake of N, P, K, Ca, Mg and micronutrients. P nutrition increased the available Nand P content of the soil. Potassium nutrition at higher rates promoted all the above growth characters, leaf area, LAI and dry matter accumulation in different plant parts. Potassium applied at 400 g plant! favoured the yield attributes and yield of crop. Application of K20 at 600 g plane 1 yielded better quality fruits with appreciable total sugars, reducing sugars, sugar-acid ratio, pulp-peel ratio and shelf life. Higher rates of K20 enhanced the uptake of N, P, K and micronutrients like iron, manganese, zinc and copper. Potassium supply at 400 g plant! was beneficial in increasing the calcium and magnesium uptake by different plant parts. Application 3 of K20 at higher rates resulted in appreciable build up of N, P and K in the soil. The combination of N, P20S and K20 applied at 300:300:600 g plant! had appreciably increased the growth characters, yield attributes, and nutrient uptake. It was comparable to that of N, P20S and K20 at 200:200:400 g planr '. The bunch yield obtained by the application of N, P20S and K20 at 300:300:600 g plant! was also comparable with that of 200:200:400 g planr '. However, mineral nutrition of N, P20S and K20 at 200:200:400 g plane! had given the maximum benefit-cost ratio of 1.96. Therefore it can be concluded from the study that application of N, P20S and K20 at 200:200:400 g plant! is beneficial for getting higher yield and maximum economic returns.
Phosphate fractions of Kerala rice soils in relation to their occurrence and pedogenesis
(Kerala Agricultural University, 1979) Aiyer, R S; Sundaresan Nair, C
to their pedogenesis was conducted. The total P content varies between 816 and 917 ppm. The Fe-P fraction is the most dominant fraction in all the soils accounting for 21.8 to 39.3 per cent of the total P in the soils. AI-P is the second most abundant P fraction, accounting up to 12.7 to 25.8 per cent of the total P. The Ca-P fraction varies between 5.9 and 103 per cent. These soils contain only 6.0 to 9.5 per cent and 2.7 to 5.6 per cent respectively of reductant-P and occluded-P. The higher Ca-P incidence in the soils under marine influence has been attributed to the reaction of soluble Ca in the sea water with reduced Fe-P compounds and the formation of more insoluble Ca-P compounds. The results indicate that continuous alluviation by periodical floods in the formation of all the soils under study coupled with the marine influence in all the soils except the lateritic alluvium of the ribbon valleys of the midlands appear to maintain their juvenility.