Abstract:
The effects of the integrated rice-crayfish farming on rice quality and its nitrogen (N) accumulation were studied in Tongling City, Anhui Province to provide a scientific basis for nitrogen management in the integrated rice-crayfish farming system. A field experiment was conducted to compare nitrogen uptake and accumulation of rice in the integrated rice-crayfish farming system with feed (RCF) and without feed (RC), with the rice monoculture only (R) as control. The yield and quality of rice in different farming systems were compared. The N input-output balance in different farming systems was also calculated. The results indicate that rice tissues under RC treatments had higher content of N than that of R at the mature stage (
P < 0.05). Likewise, RCF and RC treatments led to significantly higher N accumulation in rice tissues compared with R (
P < 0.05). Their nitrogen accumulation increased by 20.9% (RCF) and 26.9% (RC), respectively. No significant differences were found in the N content and accumulation of rice between RCF and RC treatments. Compared with R, the milled rice rate and protein content of grain under RC treatment increased by 3.0% and 8.4%, respectively. Conversely, chalky rice rate, amylose content, and gel consistency of rice reduced by 25.1%, 7.5%, and 6.6%, respectively, in RC treatment compared with R. However, RCF and RC treatments caused significantly higher N output from rice and straw than R (
P < 0.05). The N utilization efficiency of R, RCF, and RC were 0.85, 0.98, and 1.11, respectively. Altogether, the results of this study suggest that RCF and RC could promote N accumulation in rice, and increase rice quality and N utilization efficiency, whereas there exists a risk of consuming soil nitrogen. Nevertheless, no significant differences occurred in rice N utilization and rice yield between RC and RCF treatments. From the view of economic and environmental benefits, the integrated rice-crayfish farming system with appropriate feed is a high-efficient farming system to achieve sustainable development in this region.