Abstract:

The experiments of straw composting and returning to the field were carried out according to the cold climate characteristics of autumn and winter in the Northeast region and the practical operational requirements. Field composting experiments were conducted after the harvest of corn in autumn, and the environmental temperature, precipitation, straw pile temperature and straw weight loss rate were continuously monitored. The fully decomposed corn straw was used as fertilizer and applied to the field for three consecutive years. The soil organic matter, available nitrogen, available phosphorus, available potassium, soil porosity and bulk density were monitored as indicators. A 2-year application experiment was carried out in basic farmland and shed protected areas. The results showed that the weight loss rate of 120 d straw reached 31.53%. By using rotten straw for three years, the soil organic matter increased by 4.06-6.31 g/kg, the alkaline hydrolyzable nitrogen in soil increased by 15.08-27.35 mg/kg, the available phosphorus increased by 18.11-21.95 mg/kg, quick-acting potassium increased by 63.97-89.93 mg/kg. The soil bulk density was reduced by 0.10-0.14 g/cm³. The water holding capacity of soil in the field increased by 7.51%-9.24% (V/V). The soil porosity increased by 3.69%-5.27% (V/V) (P≤0.05). In the application experiment in basic farmland and protected areas, there was a slight increase in available nutrients and organic matter, while bulk density and field water holding capacity had a significant change. The application of decomposed straw could reduce soil bulk density, increase soil porosity and field water holding capacity and improve soil compaction issues. Decomposed straw played a significant role in improving and conserving the properties of black soil.

Key words: corn stalks, composting, northern cold region, returning the field, conservation of black soil, soil properties