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Great efforts have been devoted to assessing the effects of straw managements on greenhouse gas (GHG) emissions, global warming potential (GWP), and net economic budget in rice monoculture (RM). However, few studies have evaluated the effects of straw managements on GHG emissions and net ecosystem economic budget (NEEB) in integrated rice-crayfish farming (RC). Here, a randomized block field experiment was performed to comprehensively evaluate the effects of aquatic breeding practices (feeding or no feeding of forage) and straw managements (rice straw returning or removal) on soil NH4+-N and NO-3-N contents, redox potential (Eh), CH4 and N2O emissions, GWP, and NEEB of fluvo-aquic paddy soil in a rice-crayfish co-culture system in Jianghan Plain of China. We also compared the differences in CH4 and N2O emissions, GWP, and NEEB between RM and RC. Straw returning significantly increased CH4 and N2O emissions by 34.9-46.1% and 6.2-23.1% respectively compared with straw removal. Feeding of forage decreased CH4 emissions by 13.9-18.7% but enhanced N2O emissions by 24.4-33.2% relative to no feeding. Compared with RM treatment, RC treatment decreased CH4 emissions by 18.1-19.6% but increased N2O emissions by 16.8-21.0%. Moreover, RC treatment decreased GWP by 16.8-22.0% while increased NEEB by 26.9-75.6% relative to RM treatment, suggesting that the RC model may be a promising option for mitigating GWP and increasing economic benefits of paddy fields. However, the RC model resulted in a lower grain yield compared with the RM model, indicating that more efforts are needed to simultaneously increase grain yield and NEEB and decrease GWP under RC model.

In order to employ appropriate management measures for rice-crayfish farming systems in the Jianghan Plain, it is critical to evaluate how this process affects the soil quality. By taking 76 soil samples from three different crayfish aquaculture periods (≥10 years (Y10), 4-6 years (Y4), and 1-–2 years (Y1)) from paddy fields and using traditional rice planting patterns as controls (rice-wheat, rice-grape, and rice monoculture as CK), we surveyed the influence of different years of rice-crayfish development in rice fields on the soil quality using an integrated soil quality index (SQI). The results showed that crayfish aquaculture significantly affected the soil quality of the paddy fields. The SQI assessed the soil organic carbon (SOC), microbial biomass carbon (MBC), total potassium (TK), oxidation-reduction potential (Eh), and Mn(II). The highest SQI values were detected in the Y10 rice-crayfish system, and the lowest in the traditional paddy field. Mn(II) was the dominant soil quality factor, contributing 34.24 % to the SQI value. The relativity analysis also demonstrated that the SQI values were inversely correlated with Mn(II), and this may be used as a characteristic indicator to evaluate the soil quality of rice-crayfish systems in paddy fields. Overall, crayfish aquaculture in rice fields significantly improved the soil quality. The findings of this research showed that the use of a minimum data set (MDS), the SQI, is a potent means for assessing the soil quality of rice-crayfish systems.

The biomass stoves have been applied thousands of years in Chinese rural areas, while the thermal efficiency of the traditional biomass stove is low and redundant heat is utilized inadequately. In this paper, the multifunctional biomass stove which has the heat collector inside was designed and transformed based on the structure analysis of the traditional biomass stoves. Furthermore, the related performance indicators were proposed, which are applicable for the multifunctional biomass stove. In addition, the multifunctional biomass stove was compared with the traditional biomass stove in the thermal performance by testing. The results which were obtained by synthesizing the performance indicators showed that the thermal efficiency of the multifunctional biomass stove was 30.79% higher than the traditional biomass stove based on the kang surface temperature. The multifunctional biomass stove had a preferable thermal performance than the traditional biomass stove. Thus, the multifunctional biomass stove can reduce the energy consumption and is applicable in rural buildings.