A study of soil ammonium nitrogen in some soils of Manitoba

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Patil, Bheemanagouda Neelanagouda
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A study was made of soil ammonium nitrogen of different types of soils of Manitoba. Methods used were: 1. Potentially available Nitrogen (PAN) determined according to the method suggested by Purvis and Leo (73); 2. Exchangeable ammonium determined according to the method described by Jackson (54). The PAN and exchangeable ammonium nitrogen were evaluated by statistical comparison with two weeks incubation nitate nitrogen. In general PAN values, in forty-five surface soils of Manitoba Province, correlated highly significantly with two weeks incubation nitate nitrogen... The recoveries of the added ammonium nitrogen as exchangeable ammonium by extracting with 10 per cent NaCl solution of pH 2.5, and as nitrate after four weeks of incubation of soils at 30oC reveal that considerable amounts of added ammonium nitrogen is lost in calcareous soils. This loss is attributed mainly to gaseous loss of ammonia as these calcareous soils have alkaline pHs. Another possible reason is that larger amounts of calcium present in these soils might be inhibiting nitrification as addition of 20 per cent of calcium carbonate to a highly fertile soil has reduced its nitrification about 74 per cent. Nitrogen uptake percentages of ammonium nitrogen added to calcareous soils are also lower than those for non-calcareous soils. The nitrogen uptake percentages in general are comparable to the recoveries of added ammonium nitrogen to soils as exchangeable ammonium by extracting soils with 10 per cent sodium chloride solution of pH 2.5.