Effects of Straw Mulching and Decomposition Rate on Soil Temperature and Humidity and Maize Yield

In order to explore the effects of straw mulching and decomposition rate on soil temperature, humidity, and maize yield in northeast black soil region, comparative experiments were conducted between total straw mulching (experimental group) and leave stubble treatment of about 10 cm straw mulching (compared group) in Zhaozhou County of Daqing City in 2019 and 2020. The results showed that the decomposition rate of straw of the experimental group was only 4.3% and 4.5% in April, 17.8% and 16.8% in May, 22.3% and 27.8% in June, and the decomposition of straw was mainly concentrated in July to August. The soil temperature and humidity were significantly affected by residual straw on the ground, and the soil moisture content of the experimental group was 1.2 percentage points and 1.1 percentage points lower than that of the compared group in May. However, with the increase of straw decomposition rate, the average soil moisture content of the experimental group was about 3 percentage points higher than that in the compared group from June to September. From May to August, the soil temperature at 0 cm was restrained during diurnal warming phase, and the maximum difference between experimental group and compared group respectively was 4.8℃ and 3.8℃ in the same period. The soil temperature at 10 cm and 20 cm was evidently affected by the straw mulching in May and June, and was not significant from July to September. Compared with the compared group, the effect of soil temperature at 30 cm was significantly affected in June, but it was changed little in other months. During the daily cooling period, the soil temperature at different depths in the experimental group was decreased more gently than that in the compared group, and the effect of soil temperature preservation and soil moisture preservation was obvious. The straw mulching affected the crop emergence, the crop emergence of the experimental group affected by straw mulching was 4 d and 3 d later than that of the experimental group. At jointing stage, the plant height of the compared group was 7.3 cm and 7.4 cm higher than that of the experimental group, and the stem diameter was 0.2 cm and 0.1 cm thicker than that of the experimental group, respectively. However, the plant height and stem diameter of the experimental group were higher than those of the compared group at other stage. The maize yield of the experimental group was 10 716.0 kg/hm2 in 2019, which was 193.5 kg/hm2 higher than that of the compared group. In conclusion, the straw returned by crushing and mulching had a two-way hindrance effect on soil temperature and humidity, and the degree of straw decomposition had a certain impact on the two-way hindrance effect. The effect of straw mulching on heat preservation and soil moisture preservation promoted the growth and yield of corn. © 2021, Chinese Society of Agricultural Machinery. All right reserved.