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植物蒸腾量在腾发量中的比重一直是各国科学家十分关注却较难解决的问题。近来美国和日本等国的气象及灌溉学家偿试用植物茎热量平衡法解决这一问题,收到较好效果。 其方法原理是:在植株茎表面安装一加热器,施加一大小为Q的热量,此时,将杆茎贮热量的变化忽略不计,则装有加热器的植株部位的热量平衡方程可表述为: Q=q_f+q_d+q_u+q_s (1)式中q_f——因蒸腾流运动带走的热量 q_d——因热传导向杆茎上部移动的热 量 q_u——经传输,杆茎下部失去的热量 q_s——由加热器表面散失到周围空气 中的热量 如果将q_f用蒸腾流量和加热部位上下
The proportion of plant transpiration in the amount of evapotranspiration has always been a problem that scientists of all countries are paying close attention to but are hard to solve. Recently, the meteorological and irrigation scientists in countries such as the United States and Japan have tried to solve the problem by using plant caloric balance method and received good results. The principle of the method is as follows: a heater is installed on the stem surface of the plant and a calorific value of Q is applied. At this moment, the heat balance of the plant stem with the heater can be expressed as : Q = q_f + q_d + q_u + q_s (1) Where q_f - due to the movement of transpiration stream heat q_d-- due to heat transfer to the upper part of the stem to move the heat q_u - transmission, the lower part of the stem to lose heat q_s - Heat dissipated to the ambient air by the heater surface If q_f is to be raised and lowered with the transpiration flow and heating