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Item Extractable aluminium in the rice soils of Kerala(Kerala Agricultural University, 1979) Karthika Kutty Amma, M; Alice Abraham; Aiyer, R STwenty surface soils representing four major rice soil types of Keraia viz., the Kari, Karapadom, Kayal and low level laterites were extracted with different extractants viz.. one normal potasium chloride at different soil solution ratios, one normal ammonium acetate adjusted to different pH values and water and the alluminium estimated. Based on the results, one normal potasium chloride with a soil solution ratio of 1 :10and water were adjudged to be good for predicting toxic levels of Al in this soils. The result obtained further indicate that most of the Al extracted is of the exchangeable type in the case of Kayal and low level laterite soils, while it is not so in the case of Kari and Karapadom soils. The results of the present investigation thus project the need for a very systematic evaluation of the extractable Al content of the highly acid rice soils of Kerala in relation to the existence of Al toxicity to the rice crop.Item Phosphate fractions of Kerala rice soils in relation to their occurrence and pedogenesis(Kerala Agricultural University, 1979) Aiyer, R S; Sundaresan Nair, Cto 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.Item Availbale zinc, copper, iron and manganese status of the acid rice soils of Kuttanad, Kerala state(Kerala Agricultural University, 1975) Aiyer, R S; Rajagopal, C K; Money, N SDetermination of available zinc, copper, iron and exchangeable manganese in the [Cari, Karapadom and Kayal soils of Kuttanad region, Kerala State, revealed that all the three soil types are highly deficient in available copper (90%). Available zinc was deficient in 50% of the Kayal soils studied. High amounts of available iron in the Kari soils suggest the possibility of iron toxicity to rice in these soils. Significant and positive correlations existed between available copper on the one hand and organic carbon (r= + 0.400) and CEC (r= + 0.566! on the other. Available iron was significantly and positively correlated with organic carbon (r= +0689) and CEC (r= -f 0.566) and significantly and negatively correlated with pi! (r= - 0.425) and exchangeable Ca + Mg (r= - 0.408). The results warrant application of copper in all the three types of Kuttanad soils and of zinc in the Kayal soils.Item Potassium status of the major rice soils of Kerala state in relation to their granulometric composition(Kerala Agricultural University, 1975) Sreedevi, S; Thomas Varghese; Aiyer, R SA study on the contribution of various size fractions towards !he total K content of the five major acid rice soil groups viz., Kari, Karapadom, Kayal, Kole and low level laterites of Kerala State was conducted. The possible reason for the lack of response of potassic fertilisers in the heavy clay soils like Kari, Kole and Kayal soils is discussed. Higher incidence of coarse fractions and high content of K in such fractions from the laterites suggest the possibility of increased release of reserve K by better soil management practices like application of organic matter.Item Usefulness of sensory methods of analysis by a taste panel in differentiating the quality of cassava tubers under different manurial treatments(Kerala Agricultural University, 1975) Prema, L; Thomas, E J; Aiyer, R SFive kg. of cooked tubers from 4 treatment combinations from the two extreme levels of nitrogen and phosphorus in a fertiliser experiment conducted at Vellayani with 3 levels of nitogen (N0 = 0, N,-=75 N, = 150 kg P3O,,/ha) and 3 levels ofPItem Response of rice (variety 1R-8) to zinc as affected by levels of phosphatic fertilisers(Kerala Agricultural University, 1975) Prabha, R; Aiyer, R S; Money, N SAn attempt was made to produce phosphorus induced zinc deficiency in rice plants (var. IR-8) under pot culture conditions with 18 treatments, being the combinations of 6 levels of P and 3 levels of Zn. Yield of grain and straw were significantly increased by the application of both zinc and phosphorus. At higher doses of Phosphorus the yield of grain decreased slightly. The optimum combination of P and Zn was found to be 72.5 kg P2 Oa/ha and 25 kg ZnSOJha. The study has revealed that for the proper uptake and utilisation of zinc especially when the soil is poor in available zinc the P levels have to be kept low. High levels of P may lead to zinc deficiency. Such deficiency can be corrected by tha application of zinc in the soil.Item Influence of soluble aluminium on the yield and growth characters of the rice plant(Kerala Agricultural University, 1979) Alice Abraham; Koshy, M M; Aiyer, R SThe effect of 0, 10, 20, 30, 40 and 50 ppm aluminium on the yield and growth characters of the rice plant grown in solution culture was studied, Toxicity symptoms of aluminium were not manifested on the tops while root growth was progressively decreased in 20, 30, 40 and 50 ppm aluminium containing pots. Decrease in root growth was associated with a tendency for root branching and the formation of mere vascular traces in the root cortex. The reduced root growth did not suppress the yield.Item 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 SGreen 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.Item Effect of phorate on rhizobial nodulation in cowpea(Kerala Agricultural University, 1981) Visalakshi, A; Nair, M R G K; Aiyer, R SStudies were made on the effect of phorate granules applied along withs seeds at the time of sowing on nodulation in cowpea treated with Rhizobium a compared to nodulation in untreated seeds. In Rhizobium treated plants, phorate caused suppression of nodule development and increase In nodular size, fresh weight and dry weight. In plants untreated with Rhizobium, phorate suppressed nodule formation in the roots and stimulated nodule size and fresh wieght.Item Screening of rice varieties for tolerance to acidity(Kerala Agricultural University, 1986) Marykutty, K C; Aiyer, R SA pot culture experiment wss conducted to screen out the most tolerant variety that could be grown in a highly acid soil from among 39 varieties cultivated in Kerala. The varieties were screened for tolerance to acidity using the method of D2 statistics, selecting the important characters and thus three clusters were formed. They were characterised as tolerant, medium tolerant and least tolerant varieties to acidity. Among the tolerant varieties, Jyothi variety ranked first.