Author
Abstract
Physico-chemical properties of Vertisols in the Mwea area, the major irrigated rice area of Kenya, were investigated to develop recommendations for soil and nutrient management for intensive rice cultivation. Soil depth ranged from 0.8 to 1.8 m with dark clay layers with a heavy texture predominated by montmorillonite. Only a weak horizon differentiation was recognized in the clay layers except for a slight change in the structure with depth. Carbonates as nodules and concretions were commonly detected in deep to shallow layers. The soil chemical fertility was estimated to be medium to high in terms of major essential elements in general, except for K whose amount was found to be rather low in some areas. Available N level was medium to high for Vertisols, but it was obvious that efficient N application was essential to achieve a high yield standard considering the range of soil available N content.
Low yield was often associated with a low topographic position of the fields. In the fields with poor drainage mostly found in depressed areas, strong reduction of soil and high base concentration might disturb the root activity for nutrient uptake.
From the physical viewpoint, difficulty in plowing was a major constraint. Dry tillage could be an option to minimize water percolation into deep layers along cracks to maintain the trafficability. Incorporation of organic matter such as rice straw or upland crop residues is being tested to improve the friability of soil for better workability in dry tillage and drainage, which may also contribute to the recycling of nutrient sources like K.
References
For further details log on website :
https://www.jstage.jst.go.jp/article/jsta1957/45/2/45_2_126/_article
1) National Agricultural Research Center
Abstract
Physico-chemical properties of Vertisols in the Mwea area, the major irrigated rice area of Kenya, were investigated to develop recommendations for soil and nutrient management for intensive rice cultivation. Soil depth ranged from 0.8 to 1.8 m with dark clay layers with a heavy texture predominated by montmorillonite. Only a weak horizon differentiation was recognized in the clay layers except for a slight change in the structure with depth. Carbonates as nodules and concretions were commonly detected in deep to shallow layers. The soil chemical fertility was estimated to be medium to high in terms of major essential elements in general, except for K whose amount was found to be rather low in some areas. Available N level was medium to high for Vertisols, but it was obvious that efficient N application was essential to achieve a high yield standard considering the range of soil available N content.
Low yield was often associated with a low topographic position of the fields. In the fields with poor drainage mostly found in depressed areas, strong reduction of soil and high base concentration might disturb the root activity for nutrient uptake.
From the physical viewpoint, difficulty in plowing was a major constraint. Dry tillage could be an option to minimize water percolation into deep layers along cracks to maintain the trafficability. Incorporation of organic matter such as rice straw or upland crop residues is being tested to improve the friability of soil for better workability in dry tillage and drainage, which may also contribute to the recycling of nutrient sources like K.
References
- 1. BLOKHUIS, W. A. 1982 Morphology and genesis of Vertisols. In: Vertisols and rice soils of the tropics. Symposia papers 2. Transactions of the Twelfth International Congress of Soil Science 23-47.
- 2. FAO 1985 Fifth meeting for soil correlation and land evaluation. World Soil Resources Reports 56. pp.207.
- 3. KANTOR, W. and U. SCHWERTMANN 1974 Mineralogy and genesis of clays in red-black soil toposequences on basic igneous rocks in Kenya. J. Soil Sci. 25: 67-78.
- 4. KAWAGUCHI, K and K. KYUMA 1977 Paddy soils in tropical Asia. The University Press of Hawaii. pp.258.
- 5. MIYAKE, M. M. ISMUNADJI, I. ZULKARNAINI and S. ROECHAN 1984 Phosphate response of rice in Indonesian paddy fields. Technical Bulletin No 17, TARC. pp.78.
- 6. MOBERG, J. P. and I. E. ESU 1991 Characteristics and compositions of some savanna soils in Nigeria. Geoderma 48: 113-129.
- 7. OHU, J. O., E. I. EKWUE and O. A. FOLORUNSO 1994 The effect of addition of organic matter on the compaction of a Vertisol from Northern Nigeria. Soil Technology 7: 155-162.
- 8. YOSHIDA, S and Y. HAYAKAWA 1970 Effects of mineral nutrition on tillering of rice. Soil Sci. Plant Nutri. 16: 186-191.
For further details log on website :
https://www.jstage.jst.go.jp/article/jsta1957/45/2/45_2_126/_article
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