Effect of slow-release fertilizer on soil fertility and growth and quality of wintering Chinese chives (Allium tuberm Rottler ex Spreng.) in greenhouses.

To avoid the negative impact of excessive fertilization on vegetable production, a decreased fertilization experiment was conducted in a multi-layer covered plastic greenhouse in 2017 to 2018. Treatments included no fertilizer (CK), traditional fertilization (TF), slow-release fertilizers (SRF), and decreased fertilization with slow-release fertilizers (DSRF). Results showed that the SRF and DSRF increased leaf length (13% and 8.3%) and chlorophyll content (7.1% and 8.2%) of Chinese chives compared to TF. Similarly, DSRF was found to increase the accumulation of dry matter accumulation of roots (22%) and the dry matter accumulation of shoots (36%) of Chinese chives. Flavonoid, soluble sugar, and soluble protein content were enhanced by 18%, 8.5%, and 4.6%, respectively, in DSRF compared to TF. Nitrate content of the SRF and SRFR decreased significantly by 26% and 35%, respectively. In addition, there was a significant increase in soil nutrient and enzyme activity in the middle and late harvest of Chinese chives under DSRF compared to TF, and there was a high correlation between soil nutrients and the quality of Chinese chives. The available P and total P content significantly differed among the different greenhouse soil samples, and this significantly affected the quality of Chinese chives. The content of available P and total P in greenhouse soil was 125.07 g kg and 1.26 mg kg, respectively. Optimal quality was obtained. Hence, the application of DSRF promoted the growth of Chinese chives and improved soil fertility, thereby enhancing the productivity and quality of Chinese chives.