Abstract
The effects of pre-transplanting phosphorus application (PTPA) on the initial growth of cabbage and maize were investigated with regard to dry matter production, photosynthesis, root activities, root elongation, and nutrient absorption. PTPA did not promote the growth for a few days after transplanting, but promoted the subsequent growth in both crops. This promotive effect mainly depended on the increase in net assimilation rate (NAR), which coincided with the increase in photosynthetic rate and stomatal conductance. PTPA increased the absorption of phosphorus and potassium which were contained in the applied solution. Increase in P in leaf blades of maize also contributed to the increase in photosynthetic activity. In some case, PTPA also increased absorption of the other essential elements such as magnesium. Root activities, expressed by root respiration rate and bleeding rate from the stubble, were also improved by PTPA associated with longer root length in PTPA cabbage. These results suggested that PTPA enhanced photosynthesis and root activities, through enhanced P absorption, and it also enhanced root elongation for cabbage, which accelerated the rooting and increased water and nutrient absorption from soil. Sufficient supply of water and nutrients maintained a high photosynthetic rate, resulting in the growth promotion for a few weeks after transplanting.
