Trade-offs of dryland forage production and soil water consumption in a semi-arid area

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Drought-tolerant forage crops have huge development potential in drylands taking into account the current global challenges (climate change, natural resources overexploitation and increasing food demand). However, little is known about the trade-off among yield, nutritional quality, and soil water consumption for dryland forage farming production in semi-arid regions. This research compared the two-year yield and soil water consumption characteristics of sweet sorghum (Sorghum dochna), sudangrass (Sorghum sudanense) and forage maize (Zea mays) under natural rainfall condition. The soil water content up to 200 cm soil depth –at 10-cm intervals– and dry matter yield of the different forage crops were evaluated in a set of plots in 2017 and 2018, and the nutritional quality of these crops were measured in 2018. Three replicate plots were established for each forage crop. Results showed that the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of sudangrass were significantly lower than those of sweet sorghum and forage maize (P < 0.05). Sudangrass presented the higher in vitro dry matter digestibility coefficient (IVDMD). The yield of sweet sorghum was significantly higher than that of sudangrass and forage maize. Different soil water consumption patterns were observed among the forage crops, happening mostly in the 0–150 cm soil layer in the forage maize plots, and in the 0–100 cm soil layer in the sweet sorghum and sudangrass plots. The average daily evapotranspiration (ETd) of forage maize was about 10 % and 15 % higher than that of sweet sorghum and sudangrass, respectively. Forage sorghum presented the highest yield, less soil water consumption, and similar nutritional quality to forage maize, and thus, it is an advisable option for forage production in the soil water-limited semi-arid regions.