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There have been many studies on soil quality and crop yield using different biochar application amounts, but few studies have focused on the combination of different methods and amounts of biochar application in moderately degraded Mollisols. In this study, the methods of mixing biochar evenly with the soil of the plough layer (0–20 cm depth) [homogeneous biochar application (HO)] and burying biochar above the soil plow pan (under 20 cm depth) (heterogeneous biochar application (HE)) were used to reveal how biochar application methods influenced soil quality, crop yield and agronomic characteristics in moderately degraded Mollisols (soil organic matter (SOM), 30.33 g kg−1). The biochar application amounts were 0 (control), 10 (level 1), 20 (level 2), and 40 (level 3) t ha−1 in both the HO and HE treatments. The results showed that, compared with control, HO3 significantly increased maize yield in the first year, and HO2, HO3, HE2 and HE3 continuously increased maize yield in the next three years but not significantly. HO1 and HE1 had the lowest maize yield. HO2 tended to delay maize leaf senescence. There was a positive linear relationship between soil quality index (SQI) and biochar application amount in HO. Compared with other treatments, the pH, EC, SOM, available phosphorus, sucrase and catalase activities were highest in HO3. However, the effects of HE on soil quality and crop productivity were limited at first but gradually increased with time. Overall, HO3 was beneficial for improving the soil quality and crop productivity in Mollisols for short-term cultivation (3-year), while HE showed an effect over time. Graphical Abstract

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The adoption of water-saving irrigation strategies is required particularly for wine grape variety, which has been widely cultivated in arid and semiarid areas. To assess vine response to regulated deficit irrigation (RDI), the grape growth and berry composition under five treatments that irrigated at a certain percentage of the crop evapotranspiration (ET c) were evaluated over a 3-year period in a vineyard with the grape variety of Cabernet Sauvignon. The results indicated that RDI had a significant effect on the grape berry size and yield. The largest berry size (12.20 mm) was obtained under the T50 in 2014, while the smallest berry size (9.83 mm) one was obtained under the CK treatments in the same season. The highest individual yield occurred in the T50 treatment, with an average of 1.99 kg, followed by the T25-50 treatment. However, both weights were significantly larger than that of the CK treatment. Compared with the T50 treatments, the individual grape vine yield in the T50-25 treatments were slightly less by 16.9% for 2013, 15.3% for 2014 and 18.1% for 2015. Compared to control (CK) treatment, the soluble solid and reducing sugar contents decreased, the total acid content increased, and the sugar/acid ratio basically showed a downward trend. The treatment irrigated at 50% ET c until veraison and 25% thereafter (T50-25) increased the phenolic compound content in grape skins. The treatment received only rain water during the grape growing season (CK) and the one irrigated at 25% of the ET c crop evapotranspiration (T25) caused defoliation and negatively affected the yields and grape composition during all 3 years. Therefore, the RDI not only inhibited the vine vegetative growth but also improved the fruit quality. In terms of productivity and grape composition, the Cabernet Sauvignon grape variety was most sensitive to water stress post-veraison. Over the comprehensive consideration of yield, water-use efficiency and berry composition, the T50-25 treatment was the most efficient irrigation strategy in this area.