Prominent nitrogen uptake response to cattle feces by specific plant species

Abstract

We examined differences in nitrogen uptake by various plant species from soil to which fresh organic matter had been applied, and tried to find plants with a high response of nitrogen uptake to organic matter. Seventeen crop species were cultivated in a Brown Andosol upland field with 50 t FW ha−1 (149 kg N ha−1) of fresh cattle feces ( 14.8 g N kg−1 DW, C/N 28). Crops were: turnip, head lettuce, onion, spinach, soybean, carrot, adzuki bean, chingensai, maize, potato, sugar beet, pimento, cabbage, broad bean, squash, cucumber, and spring wheat. Plant Nitrogen uptake and nitrate and ammonium contents in soils were determined. Inorganic nitrogen was leached down the soil profile with time. The peak nitrate content was found in the soil at 0∼15cm depth at 13 days after sowing (DAS), 15∼45 cm at 79 DAS, and 45∼60 cm at 108 DAS. The order of nitrogen uptake by squash, maize, and sugar beet was organic matter > chemical fertiliser > no-nitrogen at 108 DAS. On the other hand, the order of inorganic nitrogen contents in the soils were chemical fertiliser > no-nitrogen > organic matter at 79 DAS. There was a contradiction in the order between plant nitrogen uptake and inorganic nitrogen content in the soil. These facts indicate that some crops such as squash markedly took up nitrogen under soils with low inorganic nitrogen levels when organic matter was present. This study suggests that in some cases the nitrogen uptake does not reflect the amount of inorganic nitrogen in soils. We examined the possibility of nitrogen uptake in organic form and enhancement of nitrogen mineralisationbyplants.