Abstract: In order to study the effects of maize straw returning and nitrogen application on the growth and nutrient absorption of summer maize in wheat-maize rotation system, the experiment was started from 2015 to 2019 and carried out in Renshou County, Sichuan Province.The summer maize variety was Zhenghong No. 6. The experiment was laid out in a split-plot design, with wheat season maize straw returning or not as the main factor and nitrogen level(0, 120, 180 kg/ha) as the sub-plot. After wheat harvest, summer maize was directly planted in each plot, and nitrogen application amounts were 225 kg/ha. The results showed that the soil organic matter content increased by 34.1% after wheat harvest. Similarly, total nitrogen, alkaline hydrolysis nitrogen, available phosphorus and available potassium increased by 6.64%, 7.34%, 16.2%, 14.3%(2-years mean value), respectively. Under the treatment of straw returning, the biomass of the later maize increased by 34.7%(2018), 38.8%(2019), and the yield increased by 65.7%(2018), 30.7%(2019);the biomass of the later maize improved by 29.9%, 36.7% under the treatment of 120, 180 kg/ha, respectively, and the yield increased by 41.5%, 59.4%. By maize straw returning, the uptake of nitrogen, phosphorus and potassium in the above-ground of the later maize increased by 47.2%, 58.8%, 45.0% respectively(2-year mean value). With the increase of nitrogen application rate, the absorption amount of nitrogen, phosphorus and potassium of later maize plants showed an increasing trend. In conclusion, the winter wheat-summer maize rotation planting mode in the southwest hilly region, long-term return of maize straw could improve soil fertility, improve the yield and nutrient absorption of the later maize, which was a green and resource efficient production mode in the southwest hilly region.

Key words: Maize, Straw returning, Nitrogen fertilizer, Yield, Nutrient uptake

CLC Number: 

• S143.1