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Nitrate leaching in an organic dairy/crop rotationas affected by organic manure type, livestock densityand crop
Author(s) -
Eriksen J.,
Askegaard M.,
Kristensen K.
Publication year - 1999
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.1999.tb00085.x
Subject(s) - agronomy , leaching (pedology) , manure , nitrate , crop rotation , environmental science , organic farming , plough , pasture , grazing , crop , chemistry , soil water , biology , agriculture , ecology , organic chemistry , soil science
. In dairy farming systems the risk of nitrate leaching is increased by mixed rotations (pasture/arable) and the use of organic manure. We investigated the effect of four organic farming systems with different livestock densities and different types of organic manure on crop yields, nitrate leaching and N balance in an organic dairy/crop rotation (barley–grass‐clover–grass‐clover–barley/pea–winter wheat–fodder beet) from 1994 to 1998. Nitrate concentrations in soil water extracted by ceramic suction cups ranged from below 1 mg NO 3 ‐N l −1 in 1 st year grass‐clover to 20–50 mg NO 3 ‐N l −1 in the winter following barley/pea and winter wheat. Peaks of high nitrate concentrations were observed in 2 nd year grass‐clover, probably due to urination by grazing cattle. Nitrate leaching was affected by climatic conditions (drainage volume), livestock density and time since ploughing in of grass‐clover. No difference in nitrate leaching was observed between the use of slurry alone and farmyard manure from deep litter housing in combination with slurry. Increasing the total‐N input to the rotation by 40 kg N ha −1 year −1 (from 0.9 to 1.4 livestock units ha −1 ) only increased leaching by 6 kg NO 3 ‐N ha −1 . Nitrate leaching was highest in the second winter (after winter wheat) following ploughing in of the grass‐clover (61 kg NO 3 ‐N ha −1 ). Leaching losses were lowest in 1 st year grass‐clover (20 kg NO 3 ‐N ha −1 ). Averaged over the four years, nitrate concentration in drainage water was 57 mg l −1 . Minimizing leaching losses requires improved utilization of organic N accumulated in grazed grass‐clover pastures. The N balance for the crop rotation as a whole indicated that accumulation of N in soil organic matter in the fields of these systems was small.