Soil and water loss from plots were recorded over five years (2001 to 2005) in an experiment comparing five different agricultural treatments on sloping red soil. Results showed that Bahia grass (Paspalum notatum Flugge) cover was an important factor for soil preservation, despite the presence of citrus tree planting or alley cropping in plots. The traditional rotation system (soybean [Glycine max L.]-radish [Raphanus sativus L.]) was shown to be unsuitable for soil and water conservation. However, changing crops should not be conducted during the period of high rainfall intensity. The effect of contour tillage was more significant than downslope tillage. Rainfall and rainfall erosivity did not differ significantly during the investigation period, whereas soil erosion decreased significantly over time. Planting citrus trees with Bahia grass cover generated the least runoff and sediment yield and showed a significant decreasing erosive trend with time. Thus, it proves to be an excellent choice for conserving soil and water resources on the red slopes of southeastern China.

The objective was to study soil water conservation and physiological growth of wheat (Triticum aestivum L.) using composted cattle manure applied either as mulch or incorporated with soil at 20 Mg ha−1. Haruhikari, a relatively drought‐sensitive and Hongmangmai, a relatively drought‐tolerant wheat, were the cultivars studied under both adequate and deficit irrigation. Fourteen weeks after sowing (WAS), the number of tillers and leaves was significantly reduced by 19 % and 30 % respectively under deficit irrigation and Hongmangmai produced slightly (10 %) more tillers than Haruhikari. Unlike mulching, the incorporation of manure had favourable effects on plants in terms of shoot dry mass (SDM) by 36 % and number of tillers and leaves by 40 %. Haruhikari produced substantially (29 %) greater root mass under adequate irrigation but Hongmangmai produced slightly (2.7 %) more roots and responded much better to manure use whether under adequate or deficit irrigation. As a result, Hongmangmai suffered less severe reductions in tillers and biomass under water stress. In comparison, the mulched manure treatment saved 15 % and 64 % respectively more water than the control and the treatment incorporating manure, but this advantage in water‐saving did not translate to superior plant growth. Leaf water potential (ψl) under adequate irrigation significantly exceeded that under deficit irrigation by 27 % and the ψl of Haruhikari exceeded that of Hongmangmai by 15 %. However, Hongmangmai may be considered more tolerant of dehydration since it maintained much higher net photosynthetic rates (PN) even with a lower leaf water potential. The reduction in the PN and intracellular carbon dioxide concentration (Ci) of the cultivars under deficit irrigation was on account of decreasing stomatal conductance (gs) and transpiration rate but on average, the gs of Hongmangmai significantly exceeded that of Haruhikari by as much as 0.53 under adequate irrigation and 0.22 under deficit irrigation. In conclusion, we suggest that the drought tolerance of Hongmangmai was related to its superior root growth and greater ability than Haruhikari, to efficiently utilize incorporated manure for growth under water stress.