Journal of the Rubber Research Institute of Sri Lanka

Permanent URI for this collectionhttps://dl.nsf.gov.lk/handle/1/8676

Browse

Subject: search.filters.subject.Dry matter production

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Effect of different levels of supplemental nitrogen on CO2 assimilation rates and productivity of Pueraria phaseoloides (Roxb) Benth and Desmodium ovalipolium (prain) wall. ex ridely grown in agalawatta series soil
    (Rubber Research Institute. Agalawatte, 1985) Nugawela, A.; Jayasinghe, C.K.; Aluthhewage, R.; Wettasinghe, S.
    Plant dry matter production is linked to CO2 assimilation rates, respiratory losses and total leaf area. Experiments were undertaken to determine the effect of different levels of supplimental nitrogen given to legume cover crops, on their CO2 assimilation rates and productivity. They were found to be highest for Pueraria phaseoloides and Desmodium ovaliforlium when given around 140 and 35 ppm of supplimental nitrogen. Reciprocal of specific leaf area and laef nitrogen content were also determined and they showed a positive linear relationship with supplemental nitrogen levels. How nitrogen could a influence the CO2 assimilation rates of cover crops studies are discussed.
  • Thumbnail Image
    Item
    Clonal differences in rock phosphate utilization by Hevea
    (Rubber Research Institute. Agalawatta, 1991) Dissanayake, D.M.A.P.; Dissanayake, T.; Gunasekera, R.; Jayasekera, S.
    Genotypic variability in utilization of rock phosphates including the local source Eppawale was evaluated using Hevea clones during the early immature phase. All the clones responded to P fertilization, and the responces were related to the source of fertilizers and other soil characteristics. Plants of clone RR1C 121 utilized Eppawala rock phosphate efficiently, both in Matale and Boralu soil. But, plants of clone RR1C 110 were able to use both rock phosphate sources only in Matale soils. However, responce to rock phosphate from plants of 100 was comparatively low in relation to P uptake and dry matter production. The necessity of testing these clones for the locally available phosphate source in the field scale is also discussed