Saving water with ground-cover rice production systems (GCRPS) at the price of increased greenhouse gas emissions?
2002
Dittert, K. | Lin, S. | Kreye, C. | Zheng, X. H. | Xu, Y. C. | Lu, X. J. | Huang, Y. | Shen, Q. R. | Fan, X. L. | Sattelmacher, B.
Greenhouse gas emissions of two water-saving ground-cover rice production systems (GCRPS) and a conventional flooded rice (Oryza sativa L.) production system were compared in three field experiments in China. In combination with reduced irrigation, plastic film (0.014 mm) and straw soil covers were evaluated in three major water-scarce lowland rice production regions in northern (Beijing), eastern (Nanjing), and southern China (Guangzhou, late rice). In all three regions, first results showed a pronounced effect of altered water management on greenhouse gas emissions. CH4 emissions from GCRPS were low at all locations. The exception was Guangzhou, where heavy rainfall raised soil water contents during early growth and induced high initial CH4 emissions. N2O emissions were adveresely affected by GCRPS. With both cover materials, increased N2O emissions were measured and these emissions were closely linked to N fertilization events. With respect to the different global warming potentials of CH4 and N2O the importance of CH4 declined and N2O became the most important greenhouse gas in this first experiment. Overall, a small increase in the contribution to global-warming can be expected. Within the ongoing project, management of nitrogen fertilizer will be optimized for good rice yield and to mitigate N2O emissions.
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