The growth characteristics and yield potential of rice (Oryza sativa) under non-flooded irrigation in arid region

Abstract

The objectives of this field experiment were to study the growth characteristics and yield potential of rice plants under non-flooded irrigation in arid area. Non-flooded treatments included drip irrigation with plastic mulching treatments (DIs), furrow irrigation with plastic mulching treatment (FIM) and furrow irrigation with non-mulching treatment (FIN). Conventional flooded cultivation (F) was check treatment (CK). The four drip irrigation treatments differed in the amount of water applied before and after panicle initiation. Root length density, leaf dry weight, shoot dry weight and root activity were generally higher in the non-flood-irrigated treatments (especially the drip-irrigated treatments) than in the flood-irrigated treatment at mid-tillering. However, the growth and development of rice plants were limited after jointing in the non-flooded irrigation treatments. Increasing the root/shoot ratio and root length density in the 20–40 cm depth and decreasing specific root length at 0–20 cm soil layer were important mechanisms for helping the rice plants to adapt to the non-flooded environmental stresses. Finally, the grain yield in the non-flooded irrigation treatments was lower than that in the F treatment. These low yields were mainly attributed to the low root length density at 0–20 cm depth and root activity. Generally speaking, the restricted degrees in the DIs were smaller than that in the FIM and FIN treatments. Among the DIs, both the highest grain yield (8223–8900 kg ha−1) and the highest water use efficiency (WUE) (0.63) were observed when the soil water content was kept at −30 kPa before panicle initiation and at −15 kPa after panicle initiation (referred to as the DI2 treatment). The yield in the DI2 treatment was not significantly different than that in the flood-irrigated treatment. However, WUE was 2.5 times higher in the DI2 treatment than in the F treatment. These results suggest that drip irrigation technology can be considered as a better water-saving cultivation of rice plants in arid region.