SOME PROBLEMS OF ROOT ENVIRONMENTS IN VEGETABLE GROWING UNDER GREENHOUSE CONDITIONS

The formation of soil aggregates is promoted by the use of mulches and chemical soil conditioner.
In case of sufficient watering, the salt accumulation in the soil was prevented by these treatments.
In case of insufficient watering, however, a rise in salt concentration in the soil solution beyond the concentration causing salt injury to plants was unable to prevent by the use of chemical soil conditioner and plastic-sheet mulch.
Straw mulch had a significant effect on preventing the salt accumulation in a soil.
We must think better of this kind of mulching materials as a summer mulch.

The optimum nitrate ratio determined by the method of systematic variations was below 30 percent of total six nutrients in chemical equivalents, being lower as compared with data in the past.
The reduction in amount of nitrates to supply may help to prevent the salt accumulation in a soil.
Further, raising the Anion/Cation ratio of nutrients can decrease the amount of fertilizers to supply without a decrease in crop yield.
This is much less costly than increasing the amount of fertilizers bringing a good yield and plays a role of controlling the salinity in a soil under greenhouse conditions.

Symposium on Potential Productivity in Protected Cultivation

T. Takano

https://doi.org/10.17660/ActaHortic.1978.87.21