Crop yield and soil properties of dryland winter wheat-spring maize rotation in response to 10-year fertilization and conservation tillage practices on the Loess Plateau

Drought and nutrient deficiency are the principal factors limiting crop production in arid and semi-arid areas. Conservation tillage can maintain and increase grain yields by enhancing soil fertility and conserving more soil water in the field. However, farmers without access to mineral fertilizers cannot compensate for the soil nutrient deficiencies for crop production, and the crops will suffer yield reductions. Site-specific fertilizer application with conservation tillage practice management is the key to achieving a high and sustainable crop yield. A longterm (2007-2016) two-factor, spilt-plot experiment was established to assess the effects of fertilization {balanced fertilization (BF), low fertilization (LF), conventional fertilization (CF)} and conservation tillage practices {no tillage (NT), subsoiling (ST), conventional tillage (CT)} on grain yield, soil water and soil nutrients. The aim of this experiment was to select an optimal fertilization and tillage management system for crop production in the Loess Plateau, a typical semi-arid and rainfed area of China. Ten-year data showed that subsoiling with balanced fertilization (BST) increased the grain (6465 kg ha(-1)) and straw yield (9792 kg ha(-1)), but no tillage with balanced fertilization (BNT) was observed to provide the highest economic profit for farmers (6416 yuan ha(-1)). No tillage with low fertilization (LNT) was the optimal management for soil water conservation in fields that could preserve more soil water in fallow land (mean value: 425 mm) and provide more soil water during the wheat (mean value: 387 mm) and maize (mean value: 420 mm) growth season. The LNT consumed less soil water in the crop growth season (mean value: 105.4 mm), but the BST (18.5 kg ha(-1) mm(-1)) showed a higher water use efficiency (WUE). The BF and NT showed better soil nutrient conditions (soil organic matter(SOM), available N, P and K) over the ten years and provided better soil water and balanced soil nutrient conditions for crop growth. The BNT and BST were recommended as the optimal and economic fertilization with tillage management systems for maintaining high grain yields by using soil water efficiently and enhancing soil fertility in a winter wheat-spring maize rotation on the Loess Plateau.