稻-油、稻-麦和稻-蒜轮作是中国西南地区常见的轮作模式，在确保该地区生态和经济效益以及应对全国粮食安全等问题方面发挥了重要的作用，但该地区的此轮作系统的稻谷产量和其他作物产量等比全国平均水平低1.25%-14.7%。利用机器学习构建智能决策系统分析各轮作系统投入产出特征，有利于获得更好的综合效益，但相关研究较少。因此，该研究利用data-intensive approach法，基于机器学习构建智能决策系统，以期为提升西南地区稻-油、稻-麦、稻-蒜轮作的综合效益提供依据。研究结果表明，在稻-蒜系统中，高肥料投入的基础上增加种子投入可提高产量和肥料偏生产力，最终实现最佳综合效益的概率为10%；在稻-油系统中，增加氮肥用量并且减少钾肥用量可以获得更高的产量但易增加温室气体排放，导致该系统仅实现次优效益且概率为8%；在稻-麦系统中，减少氮肥和磷肥的施用可以增加产量和肥料偏生产力，但实现最佳综合效益的概率仅为8%。基于随机森林模型的预测分析，在稻-蒜系统中减少25%的氮肥、增加8%的磷肥和74%的钾肥；在稻-油系统中减少54%和36%的氮肥和钾肥，增加38%的磷肥；在稻-麦系统中减少4%的氮肥并增加65%的磷肥和23%的钾肥，这些措施可以在不同程度上进一步提高轮作系统的综合效益。因此，该研究结果为中国西南地区稻-油、稻-麦和稻-蒜系统中通过优化农业投入以获得更高的综合效益提供了新见解。

To optimize the spatial distribution of cotton bolls and to increase the yield, the relationship between yield components and boll spatial distribution was investigated among different Bt (Bacillus thuringensis) cotton varieties.  A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.  The lint yield of Jiman 169 (the average yield from 2013–2017 was 42.2 g/plant) was the highest, i.e., 16.3 and 36.9% higher than Lumianyan 21 (L21) and Daizimian 99B (99B), respectively.  And the differences in boll weight among the three cultivars were similar to the lint yield, while the others yield components were not.  So the increase in lint yield was mainly attributed to the enlargement in boll weight.  However, the change in fiber quality was inconsistent with the lint yield, and the quality of L21 was significantly better than that of Jimian 169 (J169) and 99B, which was caused by the diversity of boll spatial distribution.  Compared with 99B, the loose-type J169 had the highest number of large bolls in inner positions; the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.  And approximately 80.72% of the lint yield was concentrated on the inner nodes in Jiman 169, compared with 77.44% of L21 and 66.73% of 99B during the five-year experiment.  Although lint yield was significantly affected by the interannual changes, the lint yield of J169 was the highest and the most stable, as well as its yield components.  These observations demonstrated the increase in lint yield was due to the increase in boll weight, and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.

Long-term continuous cropping of soybean (Glycine max), spring wheat (Triticum aesativum) and maize (Zea mays) is widely practiced by local farmers in northeast China. A field experiment (started in 1991) was used to investigate the differences in soil carbon dioxide (CO2) emissions under continuous cropping of the three major crops and to evaluate the relationships between CO2 fluxes and soil temperature and moisture for Mollisols in northeast China. Soil CO2 emissions were measured using a closed-chamber method during the growing season in 2011. No remarkable differences in soil organic carbon were found among the cropping systems (P>0.05). However, significant differences in CO2 emissions from soils were observed among the three cropping systems (P<0.05). Over the course of the entire growing season, cumulative soil CO2 emissions under different cropping systems were in the following order: continuous maize ((829±10) g CO2 m-2)>continuous wheat ((629±22) g CO2 m-2)>continuous soybean ((474±30) g CO2 m-2). Soil temperature explained 42-65% of the seasonal variations in soil CO2 flux, with a Q10 between 1.63 and 2.31; water-filled pore space explained 25-47% of the seasonal variations in soil CO2 flux. A multiple regression model including both soil temperature (T, °C) and water-filled pore space (W, %), log(f)=a+bT log(W), was established, accounting for 51-66% of the seasonal variations in soil CO2 flux. The results suggest that soil CO2 emissions and their Q10 values under a continuous cropping system largely depend on crop types in Mollisols of Northeast China.

The extracts from hulls, brans and flours of Fagopyrum esculentum Möench (FEM, three varieties) and Fagopyrum tartaricum L. Gaerth (FTG, seven varieties) were screened for free and bound phenolic content or total phenolic content (TPC), as well as 1,1 diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging activity and reducing power. Free phenolics were predominant in buckwheat hulls, brans and flours. FEM hulls extract exhibited the highest reducing power and DPPH free radical scavenging activity with the average EC50 84.54 μg mL-1 and IC50 11.54 μg mL-1 respectively, FTG brans extract had the highest average TPC (24.87 mg GAE g-1 DW), and FEM flours extract showed the lowest TPC, reducing power and radical scavenging activity. Furthermore, the correlations among TPC, DPPH free radical scavenging activity and reducing power of all the samples were investigated. The rank correlation coefficient (rs) between reducing power and DPPH free radical scavenging activity of buckwheat hulls, between TPC and DPPH free radical scavenging activity of buckwheat flours were 0.76 and 0.79, respectively (P<0.05). However, there is no significant correlation between the remaining indexes of hulls and flours, as well as the ten buckwheat brans. This result indicated that some non-phenolic compounds also contributed to the total antioxidant activity in hulls, brans and flours of buckwheats. This study demonstrated that buckwheat hulls and brans, rather than flours, are good source of antioxidants.