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The nitrogen content of potato ( Solanum tuberosum L.) tubers in relation to nitrogen application—the effect on amino acid composition and yields
Author(s) -
Millard Peter
Publication year - 1986
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.2740370203
Subject(s) - nitrogen , dry matter , chemistry , amino acid , methionine , sowing , composition (language) , agronomy , solanum tuberosum , yield (engineering) , cystine , horticulture , food science , biology , biochemistry , cysteine , enzyme , organic chemistry , linguistics , philosophy , materials science , metallurgy
The effect of nitrogen application on the nitrogen content and yield of amino acids from potato tubers was studied in one experiment in 1983 and two in 1984. Increasing fertiliser N over the range 0–250 kg ha −1 raised tuber nitrogen concentrations from 0.68–0.81 to 1.27–1.49% DM. Applying half the fertiliser on the seedbed and half at tuber initiation did not increase tuber nitrogen concentrations compared with a single broadcast application at planting. Increasing tuber nitrogen concentrations had little effect upon the proportion recovered in amides or the different amino acids. Yields of some nutritionally essential amino acids were, therefore, substantially increased up to a maximum of 256 kg ha −1 in 1982 and 308 and 384 kg ha −1 in 1984 at the highest fertiliser level. These yields were significantly higher ( P <0.01) than those found with the nitrogen application rate optimal for tuber dry matter production (213, 195 and 331 kg N ha −1 , respectively) in the same experiments. Methionine and cystine were the limiting essential amino acids. As the amount of each amino acid contained in a unit weight of fresh tuber increased with nitrogen supply, application of more nitrogen than is needed for maximal tuber dry matter production increased protein yields without decreasing the nutritional quality.