Chlorophyll-type compounds in soil
The quantities of chlorophyll-type compounds in a group of 24 arable soils were significantly correlated with nitrogen uptake (r=0.79 and yield (r=0.84) of ryegrass grown in pots in the glasshouse. Partial correlation coefficients showed the amounts of mineral N released on incubating the rewetted air-dry soils were related both to chlorophyll units (measure of chlorophyll-type compounds) and organic C. The chlorophyll units (CU) apparently represented some fraction of organic matter that liberated inorganic nitrogen, because the quantities of chlorophyll-type compounds in the soil were too small (only 0.5–3.0 pounds per acre) to supply this nitrogen. It is likely that the compounds were a residue that resisted decomposition. The CU in soil that had been ploughed from ley decreased very slowly during 3 years of arable cropping.
KeywordsNitrogen Organic Matter Chlorophyll Plant Physiology Partial Correlation
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