Effects of tillage on winter wheat production in Mediterranean dryland fields

Abstract

ABSTRACTThe 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 (3897 kg 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 m2 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 (488 mm). 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 m2. Our study revealed that in the short term, under semi-arid conditions, only the adoption of NT system (rather than MT) showed economic benefits.