Short- and long-term effects of rice straw application on nitrogen uptake by crops and nitrogen mineralization under flooded and upland conditions

• Published in: Plant and soil 2003-04, Vol.251 (2), p.291-301
• Main Authors: Takahashi, Shigeru, Uenosono, Shigeru, Ono, Shinichi
• Format: Article
• Language: English
• Subjects: Acid soils; Agricultural soils; Biological and medical sciences; Cereal crops; Corn; Dry matter; Flooded soils; Fundamental and applied biological sciences. Psychology; Highlands; Incubation; Mineral fertilizers; Mineralization; Nitrogen; Organic soils; Rice; Rice fields; Rice soils; Rice straw; Soil fertility; Soils; Upland soils
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/A:1023006304935

We investigated short- and long-term effects of rice straw application to paddy soils on crop growth, mineralization of straw N, and soil N supply under flooded and upland conditions. For investigating the short-term effects, pot and laboratory incubation experiments with 15N-labeled rice straw were conducted. In the incubation experiment over 90 days at 25°C, 23-24% of N in the 15N-labeled rice straw was mineralized under upland and flooded conditions. In the pot experiment, 13-14% of N in the 15N-labeled rice straw was taken up by maize (Zea mays L.) and paddy rice (Oryza sativa L.). These values were greater than those with the 15N-labeled rice straw compost, however, N derived from the rice straw contributed to soil inorganic N and N uptake by crops only a small extent under flooded and upland conditions. Continuous application of rice straw (5 Mg ha-1 year-1 for 12 years) increased soil total N and total C. Nitrogen uptake by paddy rice, upland rice and maize in the field experiment, and inorganic N in the incubation experiment over 91 days at 25°C increased in the soil with the continuous rice straw application compared with the soil without rice straw application. Gross rates of N mineralization under flooded conditions also increased by the continuous rice straw application. The degrees of increase in N uptake by paddy rice and upland crops and increase in gross rates of N mineralization by continuous rice straw application were higher than the degree of increase in total N in the soil. Continuous application of rice straw contributed to the improvement of soil fertility and the promotion of growth and N uptake by paddy rice and upland crops, while short-term effects on dry matter production and N uptake by crops were little. The appropriate timing of rice straw incorporation and combination use of rice straw and mineral fertilizer would improve the short-term effectiveness.