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Item Soil water extraction pattern of coconut (Cococs nucifera L.) in relation to soil compaction(Coconut Research Institute. Lunuwila, 1998/1999) Vidhana Arachchi, L.P.; Yapa, P.A.J.; Mapa, R.B.; Somapala, H.Effect of soil compaction on the gowth and activity of coconut roots in two soil series, namely, Andigama series (gravelly soil) and Madampe series (sandy loam soil) was studied. The effective root zone of coconut in relation to water sbsorption process under natural soil compaction were also investigated. Soil compactin and soil moisture absorption ability was determined using cone penetrometer and neutron scattering methods, respectively. Coconut root distributution in Andigama and Madampe series showed that 75%-80% of roots of adult coconut palms were localised in a depth ranging from 20 cm to 100 cm. About 5% of the roots were located beyond the 100 cm depth and 15% -20% was confined to the top layer (0-20 cm) of soil. Root growth of coconut in the two series did not show any significant differences. However, the root activity in the Madampe series, with respect to moisture absorption was higher that that of the Andigama series due to low compaction of the former. Results also showed that soil compaction higher than 250N/cm restricted the activity of coconut roots in the Andigama series for moisture absorption up to a distance of 2m away horizontally from the base of the tree and the highest moisture extraction was observed at m distance. High moisture extraction by coconut roots was confined to a depth ranging of 20 to 120 cm and of 20 to 250 cm in soils of Andigama and Madampe series, respectively, due to differences in soil compaction levels. It was condluded that soil compaction limits the water absorption ability of coconut roots vertically from the base of the tree, rather than coconut root growth and penetration.Item Characterization of soil water movement in reddish brown earth soils (alfisol)(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 1990) Pathmarajah, S.; Mapa, R.B.Item Sustainable soil management in the 21st century(Faculty of Agriculture, University of Ruhuna. Kamburupitiya, 2003) Mapa, R.B.Item Soil water dynamics in alley cropping systems in the dry zone of Sri Lanka(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 2001) Keerthisena, R.S.K.; Mapa, R.B.; Yapa, P.A.J.Item Soils of Muthurajawela wetland and their applicability to agriculture(Soil Science Society of Sri Lanka:Colombo, 2003) Idamekorala, P.; Mapa, R.B.Item Aggregate stability of major soils in the wet zone of Sri Lanka(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 1997) Jayalath, K.D.D.; Mapa, R.B.Item Litter accumulation from Mucuna bracteata cover crop and its effects on some soil chemical properties in rubber plantations(Rubber Research Institute. Agalawatta, 2010) Chathurika, S.; Samarappuli, L.; Mapa, R.B.Item Use of effective micro-organisms (EM) and urea in accelerating the decomposition of rice straw(Faculty of Agriculture, University of Ruhuna. Kamburupitiya, 2004) Herath, H.M.J.K.; Wickramasinghe, W.M.D.B.; Mapa, R.B.Item Fertility evaluation for wet zone soils of Sri Lanka(Soil Science Society of Sri Lanka:Colombo, 1999) Mapa, R.B.Item Spatial variability of soil texture, organic carbon and cation exchange capacity of a reddish brown latasolic soil in a slopy landscape(Soil Science Society of Sri Lanka:Peradeniya, 2011) Nayanaka, V.G.D.; Vitharana, U.W.A. .; Mapa, R.B.
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