Effects of drip tape placement position and dripper type on root distribution, N use efficiency and yield of cotton under drip irrigation in Xinjiang, China

Context

Drip irrigation technology has been widely used in cotton fields in Xinjiang of China. The placement of drip tape and the type of dripper directly influence the distribution of soil moisture and nutrients, thereby affecting root growth and nutrients uptake. However, the effect of drip tape placement position and dripper type on N use efficiency (NUE) and yield of cotton is still unclear.

Method

In this study, two placement positions of drip tape (in wide (W) or narrow (N) rows of cotton plant) and two types of dripper (single-wing labyrinth dripper (L) or embedded dripper (E)) were evaluated, resulting in four treatments (LW, LN, EW, EN).

Results

After 24 h fertigation, EW and EN treatments exhibited deeper soil moisture penetration than LW and LN treatments, while LW and LN showed more uniform moisture distribution in the 0–20 cm soil layer. The soil NO₃^--N of LW, LN and EN treatments were mainly concentrated in the narrow rows, while that in the EW treatment was concentrated in the wide rows. The root length density (RLD) distribution of LW, LN and EN treatments coincided with soil moisture and NO₃^--N patterns. Compared with EW and EN treatments, LW and LN treatments increased cotton RLD by 12 %-34 % and root surface area by 9 %-23 %. Compared with EW and EN treatments, the LW treatment significantly increased cotton yield and NUE by 12 %-15 % and 37 %-53 %, respectively.

Conclusion

Therefore, drip tape with single-wing labyrinth dripper placed in wide rows enhances cotton root growth and nutrients uptake, thereby increasing NUE and yield. This research contributes to optimizing drip irrigation configurations and improving cotton yield and NUE under drip irrigation in Xinjiang.