Experimental Study on the Application of “Dry Sowing and Wet Emergence” Drip Irrigation Technology with One Film, Three Tubes, and Three Rows

In order to alleviate the shortage of water in Xinjiang cotton fields, to ensure the sustainable development of the cotton industry in southern Xinjiang, it is necessary to determine a suitable “dry sowing and wet emergence” water quantity plan for cotton fields in southern Xinjiang to change the current situation. In this study, to explore the irrigation regime of “dry sowing and wet emergence” for cotton in Korla, Xinjiang, by combining field experiments and modeling simulations, the effects of different irrigation amounts on the water–heat–salt and seedling emergence characteristics of “dry sowing and wet emergence” cotton fields were investigated; the soil, water, and salt transport under different irrigation regimes was simulated by using HYDRUS-2D, and the seedling emergence rate of the cotton under different irrigation regimes was obtained through the establishment of a regression model. The results indicated that, in the field experiment, the soil water content of the 0−40 cm soil layer showed an overall trend of first increasing and then decreasing with time, while the soil salt content showed an overall trend of first decreasing and then increasing over time. The soil water content at the drip heads and cotton rows position, as well as on the 15th day, increased by an average of 5.58 cm3·cm−3 compared to before irrigation, and the soil salt content decreased by an average of 2.74 g/kg compared to before irrigation. In the irrigation water range of 675−825 m3/hm2, reducing the irrigation water amount increased the cotton emergence rate by 3.86% and the cotton vigor index by 70.53%. After the model simulation, it is recommended to choose the cotton “dry sowing and wet emergence” irrigation regime with a low to medium water amount (300−450 m3/hm2) at 14-day intervals or a low to medium water amount (300−375 m3/hm2) at 7-day intervals, which can obtain a higher seedling emergence rate.