Nitrogen absorbing characteristic and nitrogen fertilizing method of small turnips [Brassica campestris] in different cropping types
2007
Saitou, K.(Chiba-ken. Agriculture Research Center (Japan)) | Andou, T. | Yamaki, A.
Spring-, summer-, and autumn-harvest cultivations and tunnel-covered winter-harvest cultivation of small turnips were studied for nitrogen absorption characteristics, such as flux in nitrogen absorption, harvest-time nitrogen absorption for total target yield, nitrogen absorption in a plot of no nitrogen application, and the recovery rate of fertilizer nitrogen. These values and total yields were used to find a proper method for nitrogen application. 1. Judging from flux in nitrogen absorption, readily available fertilizers are appropriate as a basal dressing for the spring-, summer-, and autumn-harvest cultivations; slow release fertilizers are appropriate for the winter-harvest tunnel cultivation. No top dressing was necessary for any of the cropping types. 2. The proper amount of nitrogen application judged from the nitrogen absorption characteristics and the total yields was 9 kg/10a for the spring-harvest cultivation, 3 kg/10a for the summer-harvest cultivation, 9 kg/10a for the autumn-harvest cultivation, and 12 kg/10a for the winter-harvest tunnel cultivation. 3. The concentration of nitrate-nitrogen in the soil water calculated from nitrogen balance resulting from the proper amounts of nitrogen application was 10 mg/L or less with all the cropping types. However, the concentration could be higher than 10 mg/L when a number of cropping types of small turnips including the winter-harvest tunnel cultivation were planted.
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