北日本の無施肥栽培における水稲収量の地域間変異とその寄与要因

日本作物学会紀事

杉山 修一¹  細谷 啓太² 

[1] 弘前大学農学生命科学部;岩手大学大学院連合農学研究科

关键词: 収量;    水稲;    窒素;    日平均気温;    農家水田;    無機化;    無施肥;    Average air temperature;    Farmer's field;    Nitrogen mineralization;    Rice;    Unfertilized;    Yield;   

DOI  :  10.1626/jcs.85.266

学科分类：农业科学（综合）

来源: Nihon Sakumotsu Gakkai / Crop Science Society of Japan

【 摘 要 】

Unfertilized crop cultivation system (unfertilized cultivation) is believed to reduce the yield markedly. However, some rice farmers using unfertilized cultivation attain high yields, which are comparable with those obtained in conventional farming. In the present study, we surveyed 16 rice farmers employing unfertilized cultivation in Aomori, Iwate, Miyagi, and Niigata prefectures. Our objective was to identify factors contributing to yield variation. During 2011-2013, the mean annual rice yield obtained by these farmers was 300 kg per 10a; however, some farmers consistently achieved annual yields of 420-480 kg per 10a. The yield was highly correlated with the grain number per m2, especially with the panicle number (r=0.92***). In addition, the panicle number showed a strong correlation with the average air temperature from transplanting to 43 days before heading (r=0.66**). We conducted a rice growth experiment in pots using unfertilized paddy soil and transplanting at four different days. The tillering rate was highly correlated with the average air temperature during the growing period (r=0.92***). The results of path analysis based on multiple linear regression revealed that the effects of air temperature on the tillering rate were derived from a direct effect on rice growth (57%) and from increased nitrogen mineralization in the soil (43%). Our findings indicate that ensuring an adequate accumulated temperature during the early vegetative growth period is crucial in unfertilized rice cultivation in northern Japan.

【 授权许可】

Unknown