4.Journals Published in Sri Lanka

Permanent URI for this communityhttps://dl.nsf.gov.lk/handle/1/6840

Browse

Author: search.filters.author.Yapa, P.A.J.Subject: search.filters.subject.Agriculture

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    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.
  • Thumbnail Image
    Item
    Accumulation of free proline in bark and latex of Hevea brasiliensis affected by brown bast
    (Rubber Research Institute. Agalawatta, 1986) Wickramasinghe, S.I.; Yapa, P.A.J.; De Soysa, T.V.W.
    Free proline accumulation in clone RRIC 101 of Hevea brasiliensis was investigated. The bark and the latex samples collected from both healthy and brown bast effected trees were analysed for free prline content. The average bark proline concentration/unit present in the brown bast trees was found to be considerable higher (P = 0.10) than that of healthy trees. The accumulation of free proline in latex was found to be significant in brown bast trees.
  • Thumbnail Image
    Item
    Serum protein patterns in the healthy and brown bast affected trees of Hevea
    (Rubber Research Institute. Agalawatte, 1985) Prematillake, S.P.; Yapa, P.A.J.; Bamunuarachchi, A.
    Serum protein patterns of healthy and brown bast affected Hevea trees of six clones viz, RRIC 7, RRIC 100, RRIC 101, RRIM 600 and PB 86, were investigated. Total protein content in serum decreased noticeably in all six clones when affected by brown bast, the highest reduction being 50perc. in PB 86. Gel electrophoretic separation of serum proteins complemented these findings, with the disappearence of a number of bands and reduced intensity of the remaining bands. Protein content at different heights showed a high degree of reduction extending upwords from the tapping panel. Proteins are indicative of the spread of brown bast to neighbouring tissues at varying degrees although they may not in a noticeable changes in external appearence or in latex yields.
  • Thumbnail Image
    Item
    Use of Rubber Factory Effluent as a Fertilizer for Young Hevea Plants
    (Rubber Research Institute. Agalawatta, 1993) Soyza, S.; Yogaratnam, N.; Yapa, P.A.J.
    The effect of application of crepe factory effluents on the growth of young Hevea plants was investigated.Five treatments namely normal fertilizer, half normal fertilizer diluted serum 1:1, diluted serum 1:1, diluted serum 1:2 undiluted serum were tried out.Significant growth improvement in both height girth were observed with all 4 serum treatments, after the 20th week.
  • Thumbnail Image
    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.