Reprints

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1975

Browse

Author: search.filters.author.Aiyer, R SSubject: search.filters.subject.Rice soils

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Extractable aluminium in the rice soils of Kerala
    (Kerala Agricultural University, 1979) Karthika Kutty Amma, M; Alice Abraham; Aiyer, R S
    Twenty 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.
  • No Thumbnail Available
    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 S
    Determination 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.
  • No Thumbnail Available
    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 S
    A 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.