VI. WATER CONTROL AND MEASUREMENT - MEASUREMENT OF PLANT WATER STATUS OF GREENHOUSE CROPS WITH PRESSURE BOMB AND β-GAUGE
With the pressure bomb the relation of plant and soil water potential soil at decreasing soil moisture content was determined and the daily course of plant at constant soil on sunny days on plants in pots of bean, carnation, chrysanthemum, pepper, spinach and strawberry. With a pressure bomb and with a -gauge plant water status was followed in a crop of roses in a greenhouse with fan and pad cooling. The pressure bomb turned out to be a useful method to assess the level and variations of the plant water balance for most species studied, however, not for all. In the rose crop it indicated variations of the water balance rather sensitively, but the magnitude of plant was probably measured too low. The -gauge was sensitive enough to measure the effects of short period variations of radiation on the plant water balance.