Effect of cow-wasted compost with rice chaff on the content of nitrate in spinach [Spinacia oleracea] and nutrient and humus content of spinach grown soil in green house in Yamaguchi [Japan] Prefecture
2009
Sugita, M.(Yamaguchi-ken. Agricultural Experiment Station (Japan)) | Kuninobu, K. | Tokunaga, T.
The amount of humus, soil released inorganic nitrogen and bases have been increasing in spinach grown soil, where large amount of cow waste compost mixed with rice chaff has continuously been used in green house spinach production in central part of Yamaguchi Prefecture. This compost mixture has been adding to the soil for year round production of spinach in green house. As a result the green house soils, which contained 10% or more humus, showed increase of inorganic nitrogen content in the soil after harvest. However green house soils, which contained less than 8% of humus, showed no increased of inorganic nitrogen. However, when there were no more additions of fertilizer and compost, regardless of the amount humus, inorganic nitrogen of the soil decreased. The content of nitrate in spinach decreased with reduction of use of fertilizer regardless of the amount of humus. Results of this study were also revealed that there was correlation between amount of nitrate in spinach and soil inorganic nitrogen after harvest. The content of nitrate in spinach reduced below 3000 ppm when the amount of inorganic nitrogen in the soil was less than 10 mg/100 g after harvest.
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