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蔬菜无土栽培生产,由于所需的各种营养元素都由营养液提供,因此营养液的供给量及浓度是无土栽培中的技术重点。因营养液的浓度与电导度在一定的范围内呈正比,电导度直接影响植物的根际盐分浓度及渗透压,影响根系养分及水分的吸收,故可用较容易测定的电导度来表示营养液的浓度。同时,根据电导度还可知肥料用量的大小。电导度过低,营养缺乏,植株易徒长;电导度过高,抑制生长,造成盐渍伤害,也造成肥料用量的浪费。因此,根据栽培基质的种类及性质,通过试验确定出合理的营养液电导度(浓度)十分必要。1987年秋冬季,我们
Vegetable soilless culture production, due to the various nutrients required by the nutrient solution, nutrient solution supply and concentration of soilless culture is the technical focus. Because of the nutrient solution concentration and conductivity in a certain range is proportional to the conductivity of a direct impact on plant rhizosphere salt concentration and osmotic pressure, affecting the root nutrient and water absorption, it can be easier to measure the conductivity of the nutrient solution concentration. At the same time, according to the conductivity also know the amount of fertilizer dosage. Conductivity is too low, lack of nutrition, the plant is easy to leggy; electrical conductivity is too high, inhibiting growth, causing salinization, but also caused the waste of fertilizer. Therefore, according to the type and nature of the cultivation substrate, it is necessary to determine the reasonable nutrient conductivity (concentration) through experiments. Autumn and winter 1987, we