关键词:

免耕, 冬小麦, 生长发育, 华北平原

Abstract:

The agro-ecosystem in North China Plain is challenged by water shortage, environmental pollution with burning crop stalks and high cost. Practice of conservation tillage is very essential in North China Plain for saving water, reducing environment pollution and tillage cost, increasing the crop productivity and organic matter content of soil. With the extension of conservation techniques, zero-tillage arouses more and more attention in the area. Some investigators found yield increasing with zero-tillage, but some experiments indicated the weaker seedling and revival stage delaying of winter wheat under zero-tillage as compared with conventional tillage. The objectives of this study were to evaluate the growth and development of winter wheat under zero-tillage treatment in North China Plain and to explore the reason of the influence of zero-tillage. The experiment using the winter wheat cultivar “Kenong 9204” with three tillage treatments including conventional tillage with stubble incorporating (CT), rotary tillage with residue returning (RT), and zero-tillage with stubble direct drilling (ZT) was conducted in Luancheng Ecological Experimental Station of Chinese Academy of Sciences during 2004–2006 growth seasons. To keep similar rate of seedling emergence in all treatments, seeding rate was from 165.0 kg ha-1 (in CT and RT treatments) increased to 262.5 kg ha-1 in ZT treatment. In addition to the characteristics of growth and development of wheat, the plough layer temperature and soil water con-tent were measured. Soil temperature was measured by thermoelectric couple every day. Soil moisture was observed by TDR (plough layer soil) and neutron instrument (deeper than 20 cm) every 14 d during winter and every 7 d for the rest time. The basic seedling and tillers in three treatments ranked significantly as ZT<RT<CT (P≤0.05), but the percentage of seed-setting tillers in ZT treatment was higher than that in CT treatment. The number of basic seedling in ZT was lower than that in CT by 28.9% and 11.7% in 2004–2005 and 2005–2006 growth seasons, and lower than that in RT by 11.7% and 10.0%, respectively. The plant height, leaf area index, dry weight of wheat shoot and grain yield were the lowest in ZT treatment because of the deficient population. In ZT treatment, the maximum leaf area indices were 2.9 and 6.0 in two growth seasons, respectively. Grain yield of ZT reduced by 30.1% and 27.2% as compared with that of CT in the two growth seasons and decreased by 15.3% and 25.2% than that of RT, respectively. The water content in 0–30 cm soil layer in ZT treatment was significantly higher (P<0.05) than that in CT treatment during the whole growing period. The topsoil temperature was the lowest in ZT treatment from seedling to revival stages, indicating ZT had a “lower temperature effect”, which delays the emergence and revival of seedlings and reduce tillering rate in winter wheat. The time of seedling emergence and revival in ZT was late 1–3 and 4–5 d than that in CT and RT, respectively.

Key words:

Zero-tillage, Winter wheat, Growth and development, North China Plain