Effects of Nitrogen Fertilizer Application and Solar radiation on the Growth Response of Sorghum Seedlings to Soil Moisture

[摘要] The effects of nitrogen fertilizer application and solar radiation on the growth response to soil moisture were examined in sorghum seedlings grown in culture boxes. The effects of soil moisture(f)and amount of nitrogen fertilizer application(g)on the increment of total dry matter weight of sorghum seedling(〓W)were represented satisfactorily by the following reciprocal equation, l/〓W=A/(f-f0)+B(g+g0)/(f-f0)+C/[(f-f0)(g+g0)]+D/(g+g0)+E, where f0 and g0 were the uppermost value of unavailable soil moisture and the amount of nitrogen supplied from soil and seeds. A, B, C, D and E were coefficients. The effects of soil moisture(f)and solar radiation(S)on 〓W were expressed approximately by the following reciprocal equation, l/〓W=A/(S-S0)+B/(f-f0)+C(f-f0)+D, where S0 was the daily compensation point. These results indicated that the effects of solar radiation and soil moisture are additive, but the interaction between soil moisture and nitrogen fertilizer is not negligible. The transpiration efficiency was unaffected by soil moisture, nitrogen fertilizer and solar radiation.

[学科分类] 农业科学（综合）

[关键词] Amount of nitrogen fertilizer;交互作用効果;Growth;蒸散効率;Interaction effect;生育量;Soil moisture content;ソルガム;Solar radiation;窒素施用量;Sorghum;土壌水分含量;Transpiration efficiency;日射量