Original Papers
Effects of nitrate and moisture content in nutrient-accumulated soil on growth and nutrient uptake in eggplant (Solanum melongena L.)
2018 Volume 89 Issue 3 Pages 204-212
Details
2018 Volume 89 Issue 3 Pages 204-212
In greenhouses cultivating eggplant in Kochi, Japan, a lengthening of productive growing periods and concomitant reduction in the frequency of desalting irrigation during fallow periods had resulted in nutrient accumulation in the soil. Excess nitrate in soil may suppress water and nutrient uptake by eggplant, resulting in unsatisfactory plant growth. The objective of this study was to assess rootstock eggplant growth and nutrient uptake under different soil NO3−-N and moisture content conditions in nutrient-accumulated soil.
Pot experiments in the glasshouse were carried out at three soil NO3−-N concentrations (13.4, 26.8, and 40.2 mmolc kg−1) and three levels of soil moisture (41, 51, and 61％ of maximum water holding capacity, designated as “dry,” “middle,” and “wet,” respectively).
The height of the eggplant was more in the treatment with lower NO3−-N concentration. High soil NO3−-N reduced eggplant stem diameters and shoot dry matter weight more distinctly in the “middle” treatment than in the “wet” treatment; this is because other ion concentrations are also raised in soil treated with high NO3−-N, resulting in reduced water uptake and disturbance of nitrogen metabolism. Suppression of eggplant growth due to high soil NO3−-N can be mitigated by maintaining soil moisture at a level high enough to keep the nitrate concentration below 37 mmolc L−1 in nutrient-accumulated soil.
