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The effect of changing patterns of fertilizer applications on the major
mineral composition of herbage in relation to the requirements of cattle: a
50-year review. ACTA ACUST UNITED AC 2016. [DOI: 10.1017/s1357729800051043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Annual surveys of fertilizer practice have been conducted since 1942. Since
1985, nitrogen application rates to grass have progressively declined and
phosphorus application has been reduced since the mid 1970s. Increasing
environmental issues and the present interest in organic farming and low input
systems indicate that these trends will continue. Present overall fertilizer use
for grazing on dairy farms is about 170 kg N, 10 kg P and 20 kg К per ha. Higher
rates are used for intensive silage production, 200 kg N, 15 kg P and 50 kg К per
ha. In contrast, recommended applications are 340 kg N, 18 kg P and 25 kg К per ha
for grazing and 380 kg N, 40 kg P and 260 kg К per ha for intensive silage.
Herbage yield is controlled by the amount and timing of nitrogen fertilizer
applications. The major mineral content depends on herbage maturity within the
growth cycle; both phosphorus and potassium contents fall with declining crude
protein concentrations.
Nitrogen fertilizer generally increases both magnesium and sodium
concentration whilst potassium application decreases both. The overall effect of
combined applications is to minimize changes. In the critical spring and autumn
periods, herbage dry-matter intakes may be as important as magnesium content and
availability when assessing the risk of hypomagnesaemia in the grazing
cow.
Fertilizers, including phosphorus, even in the long term, have little effect
on the calcium and phosphorus contents of herbage. Nitrogen and phosphorus
concentrations are significantly ocrrelated in grazed herbage, silage and hay. If
environmental or economic policies were to result in a reduction in the crude
protein content of grazed herbage from ca. 250 to ca. 200 g/kg dry matter, the
phosphorus intake of a cow giving 30 kg milk per day would fall by 0·5 g/kg
dry-matter intake. This, together with any desirable additional magnesium, should
preferably be given as an oral mineral supplement rather than by attempting to
modify the mineral content of herbage.
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Eckard R. The relationship between the nitrogen and nitrate content and nitrate toxicity potential ofLolium multiflorum. ACTA ACUST UNITED AC 1990. [DOI: 10.1080/02566702.1990.9648227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Prins WH. Effect of a wide range of nitrogen applications on herbage nitrate content in long-term fertilizer trials on all-grass swards. ACTA ACUST UNITED AC 1983. [DOI: 10.1007/bf01049670] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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