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Soil and herbage potassium levels in relation to yield
Author(s) -
Hemingway R. G.
Publication year - 1963
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740140311
Subject(s) - potassium , potash , chemistry , nitrogen , agronomy , yield (engineering) , ammonium , dry matter , zoology , potassium deficiency , biology , metallurgy , materials science , organic chemistry
Results are given in respect of dry matter yields and potassium contents of an experiment where herbage was cut four times per annum over a three‐year period. A combination of nitrogen and potassium was essential for maintaining yields and 2 cwt. of muriate of potash/annum was not fully adequate if 12 cwt. of ammonium sulphate were applied each year. Additions of potassium to depleted plots in the third year of the experiment produced large and rapid improvements in yield. Progressive removals of potassium in the cut herbage were reflected in corresponding falls in exchangeable soil potassium. The mean release of non‐exchangeable potassium over the three‐year period was 2.7 mg./100 g. of soil which was only 22% of the initial exchangeable potassium value. Potassium concentrations in the herbage fell to as low as 0.4% K on the plots receiving nitrogen only and to about 1.1% K where nitrogen and potassium were given. The progressive falls in concentrations of the herbage potassium were related to the cumulative removals of potassium in the cut herbage for these treatments, but not for those plots which had received either no fertiliser or potassium only.