Types of Stover Layers Used for Salt Management Influence Sunflower Production in Saline Soils

Abstract

Three field experiments were conducted in Inner Mongolia, China, to evaluate the effects on soil water and salt distribution of maize (Zea mays L.) stover (MS), wheat (Triticum aestivum L.) stover (WS) and sunflower (Helianthus annuus L.) stover (SS) layers used alone (Exp. 1) and in combination with plastic film surface mulching (PM) (Exp. 2); their effects on sunflower yield were also examined (Exp. 3). All stover layer treatments retained more water at 0‐ to 40‐cm soil depths than was retained by the no‐stover controls in the first month, but a reverse trend occurred thereafter. The addition of PM helped maintain this advantage for 3 mo, but the advantage disappeared when PM was applied to the sunflower crop. However, stover layer treatments were consistently associated with lower soil salt contents throughout the experimental period, regardless of whether mulching or planting was applied. In addition, higher water storage and lower salt accumulation were observed in the stover layer treatments than those in the no‐stover controls in the 0‐ to 40‐cm soil layer. Reduced soluble salt concentrations were observed throughout all the stover layer treatments, except in the late growth period of sunflowers (Exp. 3). Generally, MS was more beneficial than WS or SS for resolving soil water‐ and salt‐related problems. As a result, MS+PM provided seed and biomass yields that were 13 and 23% higher than those in SS+PM, respectively, but were similar to those in WS+PM. These results suggest that MS is a top‐priority capillary cut material for sunflower production in the Hetao Irrigation District of China and similar ecological regions.