Effect of Long-Term Residue Return on Soil Organic Carbon Storage
2012, 27 (1):
To investigate the effect of maize residue return on soil organic carbon (SOC) maintenance, soil samples were collected from a long-term field experiment site after 21-year treatments involving three rates of residue return (9 375, 18 750, 37 500 kg·hm-2), yard manure application (37 500 kg·hm-2), chemical fertilizer and unfertilized control. The study was conducted in Guanzhong Plain on clay loam soil, classified as Eum-Orthic Anthrosols. Compared to the chemical fertilizer treatment, the low, middle and high levels of residue incorporation increased SOC storage by 12%, 24% and 41%, respectively, while 39% increase was found for yard manure application. The SOC accumulative coefficient after 21 years was about 5.6% for residue, and 7.2% for yard manure. The annual rate of SOC accumulation was 413 kg·hm-2, 265 kg·hm-2 and 155 kg·hm-2 for residue return at the high, middle and low levels, respectively, and 397 kg/hm2 for yard manure application. Residue and yard manure application reduced the oxidation stability of SOC and enhanced the energy state of humic substances, which means the decrease of SOC decomposition. The results indicate that residue return, both directly and indirectly (yard manure application), would significantly increase the SOC level relative to chemical fertilizer treatment and unfertilized control on clay loam soil with benefits for soil productivity and agricultural sustainability.
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