耕作方式对玉米出苗率、干物质积累及产量的影响

在吉林省公主岭市研究探讨不同耕作方式对玉米出苗率、干物质积累及产量的影响,创制提高玉米产量的适宜的耕作方法。以郑单958为试材,利用吉林省农科院长期定位试验田,对免耕、翻耕、旋耕和深松4种耕作方式下玉米出苗率、干物质重及产量比较分析。结果表明,深松耕作保苗率提高11.3%~14.6%,深松耕作显著提高玉米干物质重,其地上部分较免耕、翻耕和传统耕作提高幅度为4.9%~19.2%,地下部根系提高幅度为2.8%~90.1%。深松耕作较其他处理玉米产量增幅为8.3%~11.5%,留茬深松是促进玉米植株生长发育和提高产量的有效耕作技术。     

耕整种植联合作业工艺及配套机具

提出了适合我国北方的深松、全幅旋耕、垄台碎茬、分层深施化肥、开沟播种、扶垄或破垄和镇压等多种组合的耕整种植联合作业工艺，并设计了相应的耕整种植联合作业机。试验表明：该机各项作业指标均达到现代农艺技术要求，高效低耗，联合少耕，蓄水保墒。     

不同耕作和施氮模式对淮北地区小麦干物质积累、产量及水分利用效率的影响

为明确不同耕作和施氮模式对淮北砂姜黑土地区小麦产量及水分利用效率的影响，以烟农19为试验材料，设置旋耕+氮肥基施（RW）、旋耕+氮肥后移（RA）、翻耕+氮肥基施（DW）和翻耕+氮肥后移（DA）共4个处理，开展了大田小区试验，考察不同处理下小麦花后光合特性、干物质积累、根系分布、水分利用效率（WUE）及产量的差异。结果表明，相同施氮模式下，翻耕较旋耕显著提升了小麦产量，增产的原因是穗数、穗粒数和粒重的显著增加；相同耕作模式下，氮肥后移（RA和DA）的产量较氮肥基施（RW和DW）分别提高了25.54%和17.94%。翻耕和氮肥后移均增强了花后旗叶抗氧化酶活性，降低了丙二醛含量，显著提高了旗叶叶绿素含量和净光合速率以及花后光合同化物积累对籽粒产量的贡献率和总干物质积累量。RA、DW、DA处理较RW处理均显著提高了开花期0~60 cm土层的根长密度、根干重密度及WUE，其中WUE增幅分别为21.35%、12.71%和31.21%。综合来看，在淮北砂姜黑土地区采用翻耕结合氮肥后移的种植模式能延缓小麦花后旗叶衰老，维持叶片光合能力，增加群体干物质积累量，促进根系生长，实现产量和WUE的协同提升。     

Crop diversification increases soil extracellular enzyme activities under no tillage: A global meta-analysis

Conservation agriculture with three management principles has been widely adopted to alleviate the current global agricultural soils facing threats such as soil erosion and nutrient loss. However, unclear understanding of rational crop rotation and the lack of global quantitative assessment limit our deeper insight into soil nutrient cycling under conservation agriculture. Considering the important role of soil extracellular enzyme activities (EEAs) on soil nutrient cycling, a meta-analysis with 3238 observations was conducted on the effects of no tillage (NT) and legumes incorporation into rotation system (LRS) on soil EEAs. NT significantly increased the activities of C-acquiring, N-acquiring, P-acquiring, and oxidative enzymes by 18.3%, 17.4%, 7.1%, and 14.0%, respectively, while LRS significantly increased only P-acquiring enzymes. The combination of NT and legume cultivation had no significant effect on EEAs. In contrast, crop diversity had a positive effect on the NT-induced increase in EEAs. In addition, the extent of NT-induced changes varied depending on other factors. Through further analysis, we clarified the important factors affecting NT-induced changes in EEAs, such as climatic conditions, soil properties, and agronomic practices at the experimental sites. Overall, our findings provide insights into the understanding of the mechanisms of conservation agriculture impacts on the soil nutrient cycling.