Abstract: The invention aims at providing a pumice-based culture medium which shows outstanding characteristics as a culture medium to be used in protected horticulture. To this end, the invention provides a culture medium comprising particulate pumice having a saturated water permeability of 0.3-0.8 cm/sec and an air permeability of 15-40 cm/sec in both a dry sample and a wet sample. In another embodiment, the invention provides a culture medium having charcoal added to a culture medium comprising the particulate pumice having the above-described physical properties.

Abstract: A desalination apparatus capable of obtaining fresh water stably at low cost by utilizing low-temperature waste, wherein the desalination apparatus including a heat exchanger 92 cooperating with an evaporation can 60 so as to subject a low-temperature waste heat 11 and raw water 62 in the evaporation can 60 to heat exchange and generate water vapor 63 in the evaporation can 60; a condenser 98 cooperating with a raw water tank 72 so as to receive the water vapor 63 from the evaporation can 60, cool the water vapor 63 by subjecting the water vapor 63 and raw water 71 in the raw water tank 72 to heat exchange and obtain distilled water 76; a distilled water tank for storing the distilled water 76; vacuum means for evacuating the evaporation can 60 and depressurizing the inside thereof so as to promote generation of water vapor 63 in the evaporation can 60; and raw water supply means for supplying raw water to the evaporation can.

Abstract: A method and an apparatus for measuring the moisture content of the soil in order to enable pF value based control of irrigation in cultivation on the soil, as well as a method and an apparatus which use the first-mentioned method and apparatus to enable pF value based control of irrigation. To attain these objects, the invention provides a method for measuring the pF value (soil moisture tension) of the soil, comprising the steps of (a) preliminarily determining the correlation between pF value and volumetric water content of the soil to be measured, (b) measuring the volumetric water content of the soil, and (c) converting the value of the volumetric soil water content of the soil measured in the above step (b) to the corresponding pF value on the basis of the correlation between pF value and volumetric water content predetermined in the above step (a). Also a method and an apparatus for controlling the irrigation of the soil based on the measurement of the pF value by the method.

Abstract: The invention aims at providing a method and an apparatus for measuring the moisture content of the soil in order to enable pF value based control of irrigation in cultivation on the soil, as well as a method and an apparatus which use the first-mentioned method and apparatus to enable pF value based control of irrigation. To attain these objects, the invention provides a method for measuring the pF value (soil moisture tension) of the soil, comprising the steps of (a) preliminarily determining the correlation between pF value and volumetric water content of the soil to be measured, (b) measuring the volumetric water content of the soil, and (c) converting the value of the volumetric soil water content of the soil measured in the above step (b) to the corresponding pF value on the basis of the correlation between pF value and volumetric water content predetermined in the above step (a).

Abstract: An object of the present invention is to provide a method for forming an initial anticorrosive film in an absorption chiller-heater, by selecting optimal conditions of absorbent solution, steel material surface and film-forming operation for forming a good initial anticorrosive film. In the process for forming an initial anticorrosion film in an absorption chiller-heater having steel parts and containing an absorbent solution comprising lithium bromide as its main component and containing a lithium molybdate corrosion inhibitor according to the present invention, the main characteristics are that at least part of the steel parts of the absorption chiller-heater contacting with an absorbent solution at a temperature of higher than 100.degree. C. include a bare metal surface having an arithmetic mean surface roughness of not more than 1.0 .mu.