Non-film mulching comprehensively improved plant growth and yield of cotton in a deep-drip irrigation system under arid regions

Abstract

Plastic film mulching under drip irrigation is a key cotton cultivation technology that can save water and increase yield in arid regions. However, the long-term promotion of film mulching has resulted in increasingly serious problems related to residual film pollution. We hypothesized that deep drip irrigation and optimized irrigation can ensure the sustainability of yield of non-film cotton; thus, film is not necessary under this planting system. To address the above issues, we investigated the effects of different irrigation volumes (in m3 ha−1: W1, 2649; W2, 2925; W3, 3201; W4, 3477; W5, 3753) on the soil water and salt distribution, agronomic attributes, biomass accumulation, yield composition and water use efficiency (WUE) of non-film cotton grown under deep drip irrigation in a two-year field trial. We also explored possible ways to exploit the full potential of decreasing water consumption and enhancing cotton production. The results showed that the seed cotton yield of W3 was 7.5%, 7.1% and 3.2% higher than those of W1, W2 and W5, respectively, while it was 5.2% lower than that of W4 across the two-year study. Moreover, there was no significant difference in seed yield or WUE between the W3 and W4 treatments. Compared with the W2 treatment, the W3 treatment delayed the total growth period by only 0–2 d, the conductivity in the 0–10 cm soil layer was increased by 9.3–22.9%, and the soil water content in the 0–20 cm soil layer was increased by 1.7–4.0%. The cotton plant biomass and reproductive organ biomass increased with the amount of irrigation and followed this order W5 > W4, W3, W2 > W1. Seed cotton yield was significantly correlated with effective bolls, while WUE was negatively correlated with vegetative organ biomass at the flowering and boll setting stages. Overall, the results suggested that under the non-film conditions, an irrigation amount of 3201 m3 ha−1 would improve the eco-friendliness and efficiency of cotton production systems in arid regions.