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Information relating to the accurate quantification of the impacts of long-term conservation tillage practices on the crop yields and water use patterns of rainfed rotational cropping systems under global climate change is urgently required. The objectives of this study were to calibrate and evaluate APSIM (Agriculture Production System sIMulator) to accurately predict crop growth and development of a maize-winter wheat-soybean rotation, and to investigate the effects of conservation tillage on grain yield, water productivity and evapotranspiration on the Loess Plateau of China. This study integrated APSIM-based simulation modelling and field-level data collected from a maize-winter wheat-soybean rotation system under conventional tillage (CT) and no tillage with stubble retention of the previous crop (NTR) in Xifeng, Gansu, China. APSIM was successfully calibrated and evaluated using the root mean square error (RMSE) and index of agreement (d), indicating good performance on simulating the crop yield, dry matter biomass and soil water dynamic of the three crops for both CT and NTR treatments. Under the long-term scenario simulations (50 a, 25 rotation phases in total), the results showed that NTR improved soil water storage by 0–159 mm (72 mm on average; P < 0.01) of soil water storage before each rotation phase. The grain yield and biomass of winter wheat were significantly improved under the NTR treatment (1805 and 4309 kg ha−1 on average), but changes in maize or soybean were not significant (P > 0.05). On a system basis, the NTR treatment had significantly greater plant transpiration (Tc) and Tc/system water supply (WSsys), but lower soil evaporation (Es), evapotranspiration (ET), and ET/WSsys than treatment CT did. Additionally, Tc and Es for maize production were not significantly different between the two treatments. Grain yield water productivity (WPY) and biomass water productivity (WPB) in wheat and soybean were substantially improved by 1.9–8.0 kg ha−1 mm−1 (P < 0.05) under treatment NTR. In general, we advocated that conservation tillage has indicated great potential for improving crop/water productivity and soil water storage under rainfed conditions in the semiarid Loess Plateau region of China.

Information relating to the accurate quantification of the impacts of long-term conservation tillage practices on the crop yields and water use patterns of rainfed rotational cropping systems under global climate change is urgently required. The objectives of this study were to calibrate and evaluate APSIM (Agriculture Production System sIMulator) to accurately predict crop growth and development of a maize-winter wheat-soybean rotation, and to investigate the effects of conservation tillage on grain yield, water productivity and evapotranspiration on the Loess Plateau of China. This study integrated APSIM-based simulation modelling and field-level data collected from a maize-winter wheat-soybean rotation system under conventional tillage (CT) and no tillage with stubble retention of the previous crop (NTR) in Xifeng, Gansu, China. APSIM was successfully calibrated and evaluated using the root mean square error (RMSE) and index of agreement (d), indicating good performance on simulating the crop yield, dry matter biomass and soil water dynamic of the three crops for both CT and NTR treatments. Under the long-term scenario simulations (50 a, 25 rotation phases in total), the results showed that NTR improved soil water storage by 0–159 mm (72 mm on average; P < 0.01) of soil water storage before each rotation phase. The grain yield and biomass of winter wheat were significantly improved under the NTR treatment (1805 and 4309 kg ha−1 on average), but changes in maize or soybean were not significant (P > 0.05). On a system basis, the NTR treatment had significantly greater plant transpiration (Tc) and Tc/system water supply (WSsys), but lower soil evaporation (Es), evapotranspiration (ET), and ET/WSsys than treatment CT did. Additionally, Tc and Es for maize production were not significantly different between the two treatments. Grain yield water productivity (WPY) and biomass water productivity (WPB) in wheat and soybean were substantially improved by 1.9–8.0 kg ha−1 mm−1 (P < 0.05) under treatment NTR. In general, we advocated that conservation tillage has indicated great potential for improving crop/water productivity and soil water storage under rainfed conditions in the semiarid Loess Plateau region of China.

Weeds can harm crop growth and yield by competing for light, water, and nutrients and can produce high global potential yield losses if not controlled. However, the effects of weed diversity have not been fully examined. Here, we have used long-term data (31 years) of a cereal–legume rotation from a locality in central Spain to determine the importance of internal and external (weather and weed diversity) factors on crop yield. We used a novel methodology based on dynamic systems to explore how weed diversity and weather factors interact with crop yields. The dynamic model used here integrated internal and external factors with additive or non-linear variants. We showed that internal processes (self-regulation) are involved in wheat and legume yield temporal fluctuations. The self-regulation of crop production appears to be stronger in cereal (85%) than in legume (45%) systems, and therefore legumes seem to be more sensitive to external variations. The legume crop was not affected by weed diversity but was instead negatively influenced by average temperature for the growing season. In wheat, there was a negative, non-linear response of yield to the interaction between richness and minimum temperature for the growing season. An improved understanding of the influence of weed diversity on crop yield may help to anticipate the effects of climate change and guide management practices to maintain crop productivity under sustainable agriculture.

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