[Irrigation scheduling with a 20 cm standard pan for drip-irrigated cucumber grown in solar greenhouse in the North China Plain].

TL;DR: The drip water amount calculated with Kcp of 0.75 and the 20 cm pan were easy and feasible for cucumber cultivation in solar greenhouse in the North China Plain and there was a significant positive correlation between the pan evaporation and the reference crop evapotranspiration estimated based on a modified Penman-Monteith equation.

Abstract: An experiment was conducted in 2013 and 2014 at the Xinxiang Comprehensive Experimental Station, Chinese Academy of Agriculture Sciences. Water amount was estimated with the Ep-20 and pan coefficient. Responses of cucumber evapotranspiration (ET), yield, quality and water use efficiency (WUE) to different drip irrigation amounts (Kcp1: 0.25; Kcp2: 0.5; Kcp3: 0.75; Kcp4: 1.0; Kcp5: 1.25) were investigated. The possibility of developing drip irrigation scheduling using the 20 cm pan was also discussed. Results showed that the seasonal evapotranspiration of cucumber ranged between 129 and 314 mm, and the water consumption generally increased with the increase in drip irrigation water amount. There was no significance difference in cucumber yield between the treatments with Kcp > 0.75, and the responses of mean fruit mass, number and length to water amount had a threshold value (0.75Ep-20). Regarding the fruit quality, the contents of total soluble solids, vitamin C and soluble sugar slightly decreased with increasing the irrigation water amount, while the soluble protein content varied in order as: Kcp2 > Kcp3 > Kcp4 > Kcp1 > Kcp5. There was a significant positive correlation (P < 0.01) between the pan evaporation and the reference crop evapotranspiration estimated based on a modified Penman-Monteith equation. In a conclusion, the drip water amount calculated with Kcp of 0.75 and the 20 cm pan were easy and feasible for cucumber cultivation in solar greenhouse in the North China Plain.