Growth Stage-Based Fertigation Guideline for Greenhouse Spring Chinese Cabbage

With increasing fertigation, the precise fertigation schedule by crop growth stage has been consistently required as a guideline for stable crop production. The aim of this study is to develop the fertigation guideline for spring cabbage. To achieve this goal, we firstly investigated the nutrient uptake pattern of Chinese cabbage, which grown in pots filled with sandy loam soil in a greenhouse from April to June in 2018, and determined optimal nutrient (N, P and K) supply by growth stages. Based on soil NO3-N based recommendation, nitrogen (N) supply was divided into 4 levels (0.5N, 0.75N, 1.0N and 1.5N). Soil NO3-N concentrations somewhat differed from growth stages, and 1.5N represented the highest level. Chinese cabbage showed linear growth patterns and there was no clearly significant difference in growth and nutrient uptake by N supply levels except for 0.5N treatment. The relative growth (expressed as a dry weight) of Chinese cabbage occupied 60% and 40% of total accumulated growth (average of 0.75 and 1.0N) at 40 and 60 days, respectively. Mineral uptake (N, P, K) of Chinese cabbage by growth stages showed a linear pattern in general. N was taken up 54% and 46% of total uptake, P uptake 56% and 44%, and K uptake 59% and 41% at 40 and 60 days, respectively. Conclusively, we carefully suggest that the fertigation guideline for Chinese cabbage could save fertilizer supply through daily nutrient demand and target yield, and thus alleviate the problems in relation to nutrient accumulation in greenhouse soils. Weekly fertigation scheduling (g 10a-1) of N, P2O5 and K for greenhouse spring Chinese cabbage. Fertilization level was estimated based on mineral uptake, nutrient use efficiency and target yield (1 Mg 10a-1, FW). Growth stages Weeks after transplanting Cultivation : early April ~ late June Plant density : 4,000 plant 10a-1 N P2O5 K2O Early stage 1 - - - 2 - - - Leaf elongation 3 210 120 345 4 210 120 345 5 210 120 345 6 210 120 345 Heading 7 330 200 650 8 330 200 650 9 330 200 650 Total requirement 1,830 1,080 3,330