Browsing by Author "Cecil, S.R."
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Item Effect of NPK fertilisers on coconut grown on coral soils of Lakshadweep(1993) Bopaiah, M.G.; Cecil, S.R.Item Nutrition of Coconut(2007-02) Hameed Khan, H.; Biddappa, C.C.; Cecil, S.R.Item Nutritional Requirement of Coconut and Coconut Based Farming Systems in India(2007-02) Cecil, S.R.; Khan, H.H.The growth of young palms is influenced maximum by N, followed by K. While the effect of P has been marginal, it shows favourable interactions with N and K on growth and nut yield. Nutrient removal studies indicate that K is the dominant requirement for increasing the productivity of the palm. Increased rates of N had an adverse effect on copra content while K showed beneficial effect on all production factors. The hybrids (COD x WCT and its reciprocal cross) did not show response to levels beyond 500 g N + 500 g P2O5 + 1000 g foO/palm/year under rainfed conditions while high yielding West Coast Tall showed response to 1000 g N + 1000 g P2O5 + 2000 g K20/palm/year. Magnesium has been a limiting nutrient in coastal sandy and laterite soils and the correction of Mg deficiency leads to 30-35 per cent increase in yield. Recycling long-term resources of soil P has been suggested and 10 to 12 ppm soil available P was found to sustain adequate P supply to palms. Boron is found to be a limiting element, particularly in the north-eastern region, leading to Crown Choke disorder in the palm which is corrected by judicious application of boron. The growth of young palms and yields of bearing palms were not affected when 50 per cent of K requirement was replaced by sodium chloride (common salt). Limited organic farming with leguminous green manure crop in the coconut manuring circle is an encouraging practice for improving the fertility and nitrogen use efficiency. Coconut based high density cropping systems are found to require proportionately lower quantities of mineral fertilisers.Item Performance of Coated Nitrogen Fertilizers in Coconut Growing Soils(2007-02) Kamalakshi Amma, P.G.; Cecil, S.R.The effect of slow release fertilizers in coconut growing laterite soil by using different slow release N-carriers was evaluated. The results indicated that the Urea-N was maximum at the first day when fetilized with urea, whereas it was comparatively low for slow release sources. With the progress of time, the concentration of urea-N gradually decreased to a low value by the 15th day in urea, 60th day in neemcake coated urea and urea formaldehyde and 120th day in the case of coir dust coated urea. The ammoniacal-N was maximum for urea followed by coir dust and neemcake-coated urea. Urea formaldehyde treatment had relatively low NH4-N on first day and progressively increased upto 60 days. The NH4-N content showed a gradual decrease in the urea treated soils whereas a gradual increase from 1 to 120 days when treated with neemcake coated urea and coir dust coated urea. The nitrate nitrogen concentration progressively increased upto the 15th day in the case of other treatments. The present study reveals in general, the slow release nature of ureaformaldehyde and nitrification inhibition property of neemcake and coir dust.Item Potassium in Coconut Growing Soils(2007-02) Biddappa, C.C.; Cecil, S.R.; Khan, H.H.Coconut is generally cultivated in acid laterite, lateritic and red soils where the K content is low. The critical level of soil potassium is between 0.15 to 0.20 me 100g, equivalent to 59-78 ppm of potassium. Based on the assumption that about 80 ppm K is needed to maintain the optimum K content in the diagnostic leaf (0.8-1.0%) a desorption equilibrium model has been developed for laterite and sandy loam soils from which site specific recommendations can be successfully made. The absorption of K by coconut not merely depends on the absolute K concentrations in situ but it depends on relative concentrations of Na+, Mg++, Ca** and NH4+ in the soil. This is primarily because of the antagonism offered by these ions in the uptake of K by coconut. The selective distribution of applied K in the soil indicated that the major portion of K would be held in the boiling HN03 fraction followed by IN NH4OAc extractable form. The desorption studies showed that about 80% of the applied K could be desorbed within 2-3 extractions and further desorption is very steady upto 10 subsequent extractions.Item Residual Effect of Long-Term Phosphorus Application on Soil and Plant Nutrient Contents, Mycorrhizal Association and Yield of Coconut(1992) Hameed Khan, H.; Biddappa, C.C.; Nagarajan, M.; George V. Thomas; Cecil, S.R.Skipping of phosphorus application to adult coconut palms has resulted in reduction of salt available P in manuring circle (0-90 cm) from 43.88 ppm to 12.72 ppm over a period of 14 years and alto had no deleterious effect on P nutrition and yield of palms indicating residual effectiveness of phosphorus. Application of P at two levels showed no advantage in further enhancement of P nutrition and yield. The mean soil available P was 12.72, 30.43 and 53.29 ppm in P-0, P-1 (160 g P2O5, palm-1 year-1) and P-2 (320 g P2O5 palm-1 year-1) respectively. N, P, K. Ka, Ca, Mg, Fs, Mn, Zn, and Ca contents of the palm (Frond 14) were alto net significantly different among the treatments and ware In sufficiency range. Interestingly, VA mycorrhizal infection was more In the P-O treatment (79.3%) compared to P-1 (52.1%) end P-2 (47.1%). Population of P zolubilizing bacteria was also higher In P-0 treatment indicating the involvement of microbial population in P nutrition of coconut. The mean yield of the palms (1989) viz., 109.07, 102.36 and 108.71 nuts palm-1 per year-1 in P-0, P-1 and P-2 treatments respectively and the cumulative yield for four years did not show significant differences among the treatments, it was indicated that residual phosphates of 40 ppm in 0-90 cm in depth in the basin could sustain adquate P nutrition and normal yields for 14 years. Also sail available phosphorus status of 10-12 ppm maintained sufficiency level of P in the coconut palm. Soli available P of less than 10 ppm warrants full recommended dose to be applied (P2) and soils testing 10-28 ppm need only 59% of recommended dote (P1). For soils testing more than 20 ppm, application of phosphorus can be withheld for certain years.Item Soils and Nutrition(1991-01) Cecil, S.R.; Amma, P.G.K.Item Soils And Nutrition(1998) Cecil, S.R.; Amma, P.G.K.