An empirical description of photosynthetic area in wheat crops

Abstract

A function is presented which closely describes photosynthetic area production and senescence for winter wheat canopies. Maximum and mean rates of foliar growth and death can be calculated, together with estimations of initial canopy area and the position and value of maximum canopy area.

Temporal and spatial prediction of radiocaesium transfer to food products

“…This is a 'point model comparison'; all data in the model are related to a single coordinate with no consideration of the spatial aspects of prediction. This work has been reported by Absalom et al [11,12] and is summarised below. The second approach to model verification is to test the predictions of the model using the spatially interpolated inputs against food product contamination data collected for specified regions.…”

“…The validation data used by Absalom et al [11,12] covered a range of agricultural crop types and, for example, in the case of wheat (the crop most commonly represented in the database) the soil-plant transfer model accounted for 89% of the observed variation in radiocaesium activity concentration (n=89; P<0.001). However, wheat is grown almost exclusively on mineral soils and therefore its results are not fully representative of the full range of soil properties in England and Wales.…”

“…To achieve this the growth of arable crops (potato, leafy vegetables, root vegetables, wheat, fruit, maize, and stored grass (i.e. hay and silage)) is described by a logistic growth curve [10] and that of pasture is described by an exponential function [11]. The maximum biomass is defined by the yield and harvest index (ratio of yield to total standing crop dry weight at harvest).…”