Articles by Author: Jl Van Der Merwe

Search results for Jl Van Der Merwe

We found 154 results for you
  1. Production Capacity of Softwood Sawmills in the Republic of South Africa, Swaziland and Transkei

    Item type: Journal Article • Journal: South African Forestry Journal
    The technical and practical capacities of softwood sawmills and boxmills in the Republics of South Africa, Transkei and Ciskei and the Kingdom of Swaziland were estimated as at 30 June 1987. These estimates show that sawmills in Southern Africa are...
  2. A Technique for Producing Soil Water Retention Curves

    Item type: Journal Article • Journal: South African Forestry Journal
    Water retention curves compiled for specific soil types are an essential management and research tool in evaluating plant stress. The method of producing water retention curves by means of the 1500 kPa pressure extractor is described.
  3. Storage of <em>Pinus radiata</em> Foliage Prior To Determination of Water Potential

    Item type: Journal Article • Journal: South African Forestry Journal
    A procedure to sample and store foliage of Pinus radiata seedlings prior to determination of the water potential is described. The water potential of P. radiata fascicles sampled at pre-dawn can be maintained for seven hours by storing the foliage...
  4. Water Retention in Cultivated Forest Soils of the Southern Cape Province

    Item type: Journal Article • Journal: South African Forestry Journal
    In South Africa, commercial tree planting is restricted because of limited water resources in the soil. Therfore, it is important to recognise relevant soil characteristics and soil amelioration techniques to optimise water supply for best tree growth. The Gompertz function...
  5. Reaction of oriental tobacco to spacing and topping treatments at three levels of nitrogenous fertilizer application

    Reaction of oriental tobacco to spacing and topping treatments at three levels of nitrogenous fertilizer application

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Three levels of nitrogenous fertilizer were applied to oriental tobacco (Nicotiana tabacum L. cv. Elcatra) at different spacings and topped to 14 and 28 leaves per plant respectively. Yield, income, total nitrogen and total alkaloids of the cured leaves increased,...
  6. Amino acids in eight South African topsoil samples

    Amino acids in eight South African topsoil samples

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Amino acids were determined by gas chromatography after acid hydrolysis in eight South African topsoil samples. Total amino acid nitrogen in these samples varied from 11% to 47% of total soil-N. A difference in relative proportions of the amino acids...