›› 2018, Vol. 30 ›› Issue (4): 622-631.DOI: 10.3969/j.issn.1004-1524.2018.04.14

• Environmental Science • Previous Articles     Next Articles

Ammonia volatilization from rice-crab culture systems in northern China

WANG Ang1, 2, 3, MA Xuzhou1, 3, *, YU Yongqing4, XU Jing5, LYU Weiqun1, 2, *   

  1. 1. National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China;
    2. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China;
    3. Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture/Shanghai Engineering Research Center of Aquaculture/Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China;
    4. Panshan Research Institution of Crab Technology, Panjin 124000, China;
    5. Panshan County Meteorological Bureau, Panjin 124000, China
  • Received:2018-01-05 Online:2018-04-20 Published:2018-04-19

Abstract: In order to explore ammonia volatilization (AV) in the rice-crab system, a field experiment was carried out in Panjin, Liaoning Province. A split-plot design with two factors was arranged in this experiment, no crab and crab as the main factors, with and without fertilizer as sub-factors. The treatments included rice monoculture without fertilizer (R0M), rice-crab culture without fertilizer (R0C), rice monoculture with fertilization (R1M), and rice-crab culture with fertilizer (R1C). AV fluxes were measured via ventilation method. The results showed that seasonal AV losses from R0M, R0C, R1M and R1C fields were 8.56, 7.37, 45.64 and 41.34 kg·hm-2, respectively. N fertilization was the dominant factor which significantly affected AV losses from the treatments. AV losses from R1M and R1C treatments were 4.33 and 4.65 times than those of R0M and R0C, respectively. In fertilized rice fields, 67.6%-76.7% of the AV losses occurred during 10 days after flooding. The rates of AV losses from no fertilized paddy field were small and stable. Compared with R0M and R0C, amounts of N accumulation in rice plants were significantly increased by 53.3% and 69.7% for R1M and R1C plots. Raising crab could significantly decrease AV losses from rice fields. AV loss from R1C was 28.4% lower than that from R1M treatment after the crab rearing in paddies, but there was little difference between them during the whole rice growth period. AV losses from R1M and R1C accounted for 28.5% and 26.0% of the seasonal N inputs, respectively. Rearing crab in rice fields could increase the amounts of N accumulation in rice plants. At maturity, N accumulation in rice plants in R1C treatment was 25.0% above that in R1M treatment, while the difference of AV and N accumulation were not significant between them under no fertilization.

Key words: rice-crab culture system, ammonia volatilization, flooding water, N accumulation in rice plant, correlation

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