Relations between nutrient concentrations in plant tissues and responses of white clover to fertilisers on a gley podzol near westport
Year: 1970
Type: article
Abstract: Nutrient concentrations in plant tissues were related to yield responses in three fertiliser experiments on virgin Addison sandy loam. Yield responses indicated initial requirements for vigorous growth of white clover of at least 30 cwt agricultural limestone per acre, phosphate equivalent to 9 to 12 cwt superphosphate, 3 to 4 cwt potassium chloride, about 20 lb elemental sulphur, 5 lb each of copper and zinc sulphates, and 1 oz sodium molybdate. Indicated maintenance needs were about 5 cwt limestone per acre per annum, 6 cwt superphosphate, 3 to 4 cwt potassium chloride, and 20 lb elemental sulphur. The low retentive capacity of this soil for phosphate, sulphate, potassium, and calcium, combined with a mean annual rainfall of about 100 in., led to rapid leaching losses of nutrients and therefore abnormally high maintenance needs. Associated with yield responses, N concentrations in white clover leaves (blades plus petiole) increased with increasing rates of mono‐calcium phosphate, lime, sulphur, or sulphate, and with molybdenum applications. Because of variation between cuts in the N status of clovers, ratios of nutrients to N were examined. In these circumstances ratios appeared to be superior to absolute concentrations for diagnosis of nutrient status. Yield response to P occurred when N∶P ratios in white clover leaves were above about 14∶1. N:S ratios in clover leaves above about 18∶1 indicated S deficiency. Yield responses to copper of more than 100 percent were associated with mean Cu concentrations in leaves of copper‐deficient white clover plants of 2.0 ppm and N∶Cu ratios above 11,000:1. Slightly higher Cu levels were found in some of the most stunted copper‐deficient plants. Yield responses to zinc averaging 32 percent were associated with a mean concentration in leaves of zinc‐deficient white clover plants of 15 ppm, P∶Zn ratios above 200∶1, and N:Zn ratios above 2,200∶1.
Authors: K.J. McNaught, C. During
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W2046317996