Abstract:

Nutrient management in seedling period is a general problem in China vegetable cropping systems. Excessive or deficient nutrient supply can restrain seedling growth. In this study, traditional medium (vermiculite and turf, 1:1) as seedling substrate, different application rates of controlled release fertilizer (CRF, 19-10-11) were designed to determine proper CRF application rates and optimum mineral nitrogen content of planting substrate for cucumber (Cucumis sativus) seedlings. Shoot and root dry matter accumulating status, root morphology and nutrient uptake of cucumber seedlings were detected in this experiment. Five treatments were conducted in this trial, CRF application rates were 0, 3.42, 6.84, 10.26, 13.68 kg?m-3 respectively. The results showed that nitrogen, phosphate and potassium supplied could meet with cucumber seedlings demand; shoot and root dry matter, root length and root surface area were higher, when the CRF application rates were 3.42~6.84 kg?m-3, optimum mineral nitrogen content of planting substrate ranged from 292 mg?kg-1 to 884 mg?kg-1 at transplanting time correspondingly. The ratio of root to shoot (R/S) decreased with the CRF application rates increasing.

Key words: cucumber, controlled release fertilizer, root morphology, R/S ratio, nutrient uptake