REN R314 Lecture Notes - Lecture 24: Herbicide, Soil Fertility, Vector Calculus
20 Apr 2018
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1st step: establishment of field trials: the single tree plot approach screening trials are very useful (low cost, rapid, But does not provide area based growth response data: test of growth response (diameter, ba, volume, biomass) to nutrient additions, depends on the tree and cannot give you cubic m growth/hectare. 3rd step: operational assessment of sites: delineate sites to be fertilized by measuring the chosen variables that relate well to fertilization response. Variation small + response small: no need for fertilization. Variation small + response large: fertilization for all stands. Variation large + response large: need to identify the responsive stands. Variation large + response small: need an assessment program. Foliar analysis: critical values, vector analysis, dris analysis. Soil analysis trees have long rotations, soils do not change over time. Greenhouse based bioassay: collect soils from study site, grow seedlings to see if deficiency symptoms arise, however greenhouse responses may not reflect field studies.
