Method of plant transpiration regime assessment to estimate biomass production
2006
Havrila, J.,Slovenská akadémia vied, Bratislava (Slovak Republic). Ústav hydrológie | Novák, V.,Slovenská akadémia vied, Bratislava (Slovak Republic). Ústav hydrológie
The design and construction of amelioration systems (irrigation, drainage) should precede diagnosis of soil water regime (SWR), to estimate its need and design parameters. It means, it is needed to calculate cyclic course of so called soil water regime characteristics. As soil water regime characteristic can be used soil moisture of the soil root zone at some depth, soil water potential at certain depth, soil water content of the root zone, as they are affected by evapotranspiration and its components. Seasonal courses of soil water regime characteristics differ; therefore it is necessary to estimate statistical parameters of SWR characteristics during relatively long period of minimum twenty seasons. This paper presents method of plant transpiration regime assessment, based on seasonal canopy transpiration series, calculated retrospectively by mathematical model HYDRUS-ET. Novelty of this approach is using of the empirical relationship between the seasonal transpiration totals and biomass production (yield). Cumulative frequency distribution curve of seasonal transpiration was chosen as a basic characteristic. This approach allows estimating cumulative frequency curves of yields and cumulative frequency of potential yields. The difference is cumulative frequency of yields optimized by irrigation system. This allows to transform expected yields increase to investment and operational price and to compare expenditure to profit. This approach is illustrated on loess soil with maize canopy during 31 seasons.
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