Effect of Moisture, Nitrogen and Phosphate on Initial Growth and Shoot:Root Ratio of Cabbages Following Transplantation

Abstract

Cabbage transplants (Brassica oleracea var. capitata) nursed in cell trays are often unable to absorb sufficient soil moisture after field transplantation. To determine the optimal soil conditions necessary to enable transplants to adjust smoothly, we transplanted cabbage seedlings to pots containing soil of varying moisture and nutrient content. Plants in the moist experimental group (less than 1.7 pF-value) with fertilizer (200 mg N·L^-1) showed an exponential increase in shoot dry weight (SDW). Observations revealed that plants in the dry group (2.8 pF-value), plants in the moist group (1.7 pF-value) without fertilizer, and plants in the relatively dry (2.4 pF-value) group with fertilizer showed significantly (P < 0.01) lower SDW at 6, 9, and 12 days, respectively, after transplanting as compared with the highest growth achieved. The nutrient levels of 80, 200, and 500 mg N·L^-1, and 300, 1000, and 3000 mg P₂O₅·L^-1 were also examined. Moisture and nitrogen levels had major impacts on total dry weight (TDW). It was also revealed that deficiency in either moisture or nitrogen restricted plant growth. For the less than 1.5 pF-value experimental group, the low nitrogen content tended to increase the root portion of TDW. To promote the growth of cabbage transplants in moist soil, it is important to keep the shoot portion of TDW high with sufficient nitrogen fertilizer.