[The planting effect of cover crop in Sanjiang Plain, Northeast China].

The planting effect and the planting potential of 12 cover crops (Leguminous: alfalfa, smooth vetch, hairy vetch, red clover, white clover, common vetch; non-leguminous: sudangrass, green radish, Nitro radish, rape, kale, endive) in the Sanjiang Plain of Northeast China were comprehensively evaluated by soil penetration resistance, pre-winter biomass, root characteristics, and plant nitrogen accumulation. The results showed that all the 12 cover crops grew normally during the experimental sowing period. Compared with the control, all the cover crops successfully reduced soil compactness.

[Effect of long-term straw mulching and no-tillage on physical properties of meadow soil in cold region.].

The effects of different straw returning technology and farming system on soil physical properties is not clear in Heilongjiang Province, which is located in middle temperature zone with large amount of straw. Here, the effects of straw mulching on soil physical properties in meadow soil under no tillage conditions were studied in field experiments for eight consecutive years (2010-2017). The no straw covering (0%), 30% coverage (30%), 60% coverage (60%) and 100% coverage (100%) were disposed in the experiment.

[Variation of rhizosphere environmental factors of sugarbeet seedlings under NaCO stress and their correlation].

To study the effect of saline-alkali stress on dry mass, rhizosphere soil enzyme activities and soil microbial quantities, pot experiments were designed two sugar beet varieties, 'KWS0143' (strong tolerance to saline-alkali) and 'Beta464' (weak tolerance to saline-alkali) planted in different NaCO concentrations [0% (control), 0.4%, 0.8% and 1.