干旱区生态环境知识资源中心

The benefits of conservation agriculture (CA) and associated technologies are not equal for all agro ecosystems. This study used a field experiment to examine winter-wheat yield and weeds under conservational and conventional systems in the central region of Spain. The three tillage treatments were conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). The climatic conditions influenced wheat yield, yield components, soil water content and weeds. When the autumn-winter rainfall was abundant and constant (69.7% of annual rainfall), wheat grain yield (4465 kg ha(-1)) and yield components (3897kg ha-1 of straw biomass and 584.5 ear m(-2)) were highest. Wheat grain yield was highest with NT: 3549.9 kg ha(-1) (compared to MT: 2955.1 kg ha(-1) and CT: 2950.3 kg ha(-1)) and ear number per m(2) was significantly lower with MT (332 no ear m(-2), compared to 426 and 411.6 ear m(-2) in CT and NT-systems respectively). Soil water content, at earing stage, was the highest in NT (27.36% of soil moisture) while MT showed the lowest content (11.83% of soil moisture). The higher weed measurements (means of 2.557 plants m(-2); 1.443 species m(-2) and 2.536 g m(-2)) was with higher annual rainfall (488mm). Throughout the experiment it was the dominant presence, in MT-wheat plots, of Lolium rigidum Gaudin (with means from 4.87 to 7.71 plants m(-2)), which reduced the ear number per m(2). Our study revealed that in the short term, under semi-arid conditions, only the adoption of NT system (rather than MT) showed economic benefits.