科研之友
微信
新浪微博
Facebook
分享链接
摘要
Transpiration-use efficiency (w), defined as the ratio of biomass produced per unit water transpired, has been used to evaluate crop performance under limited water supply. However, the lack of consistency of w values through different environmental conditions has not allowed, using it as a transferable parameter. Thus, simple approaches have been developed, including: 1) w = k(Da) D-a(-1) and; 2) w = k(Eto) E-T0(-1) where k(Da) and k(ETo) are crop-dependent parameters, with the underlying concept that normalization by D-a or ET0 would accounts for the effects of climate variations on w, while these parameters would be reasonably constant across diverse environments. The objective of this study was to assess the transferability of k(Da) and k(Eto) for wheat (Triticum aestivum L.) and maize (Zea mays L.). The scarcity of experimental information and discrepancy of the methodology used, justified the use of a canopy transpiration and photosynthesis model which was developed, tested, and fitted with weather data from eight environmentally different locations to simulate values of w, k(Da) and k(Eto). The results indicated that k(Da) and k(Eto) were more variable than expected; suggesting that calibration would be desirable. A consistent trend of change of the parameter values as function of D-a or ET0 was found, which can be represented by mathematical functions, allowing transferring w, k(Da) and k(Eto) (maize). In contrast, the k(Eto) for wheat correlated weakly with D-a and ET0, but a low overall coefficient of variation (10%) allowed using an average value as a reasonable predictor of w.
- 出版日期2012-3
