Effects of potassium application dose on growth characteristics and yield of drip-irrigated peanut in Xinjiang.

To improve peanut yield under drip irrigation in Xinjiang, effect of potassium fertilizer application was investigated. Huayu 9610 (T1, a common cultivar in Xinjiang) and Heihua 5 (T2, a high yield cultivar) were used as materials at the Agricultural Meteorological Experiment Station in Wulanwusu, Xinjiang. Four potassium (K2O) fertilizer gradients were set as K0 (0 kg/hm²), K1 (150 kg/hm²), K2 (225 kg/hm²) and K3 (300 kg/hm²), and thus the potassium rates were at 15%, 40%, 30% and 15% at the seedling, pegging, podding and full fruit ripening stages respectively. Results showed that the main stem height and lateral branch length of Huayu 9610 and Heihua 5 changed parabolically with the increase of potassium application. The dry matter accumulation were the highest at K2 level, which were 84.37 g per plant and 89.37 g per plant, respectively. Compared with no potassium fertilizer, the main stem height and lateral branch length of K2 treatment increased by 17.91% and 16.56%, 7.4% and 12.31%, respectively. The number of nodules was the highest at podding stage, which was 42.0 per plant and 45.3 per plant respectively. The leaf area index increased with the increase of potassium fertilizer application, and reached the maximum at 90 days after emergence. The photosynthetic potential also changed in a parabolic shape with the increase of potassium fertilizer application rate, and reached the maximum value of 4.38 m2·d and 4.51 m2· d respectively after 75-90 days of K2 treatment. The fertilizer contribution rate and agronomic utilization rate of K2 treatment were the largest, which were 26.06% and 1.83 kg/kg (for Huayu 9610), 25.18% and 1.67 kg/kg (for Heihua 5), respectively, and the yields were 9628.38 kg/hm² and 10 368.35 kg/hm², respectively. The results showed that potassium application amount of 225 kg/hm² at K2 level could be used as reference for drip irrigation peanut in Xinjiang, China. [ABSTRACT FROM AUTHOR]