The control of the micro-climate for given practical purposes

Experiments carried out at the Central Agricultural Meteorological Observatory show that it is possible to lower or raise the temperature of the soil surface quite appreciable by covering with a layer of chalk powder or charcoal powder respectively. A thin cover of vegetation further lowers the soil temperature. It is also noted that a thin layer of chalk can bring about an appreciable reduction of evaporation from the soil. Experiments in ‘orchard heating’ indicate the possibility of minimizing frost damage by controlling air temperature during cold waves.   A brief account is also given of a micro-climatic test for drought resistance by subjecting two lots of plants to the conditions in two artificially produced environments, viz., one in which air is hot and dry and another in which the air is kept cool and humid within an enclosure of wet screens. It is found that plants which are drought-resistant have a control on transpiration while non-resistant types do not indicated such control. By comparing the transpiration ratio with the evaporation ratio it is possible to identify the resistant from the non-resistant varieties. It takes about one week per lot of plants, to complete the above test.