Extended probability model for dry matter and nutrient accumulation by crops
1995
Overman, A.R. | Wilson, D.M. | Vidak, W.
Accumulation of dry matter and plant nutrients by crops over the growing season is important to resource management for agricultural production and for meeting environmental standards. It is becoming more common in agriculture and environmental management to use mathematical models to describe such systems. In this article, an extended probability model was used to characterize accumulation of dry matter and plant nutrient uptake, both of which exhibited sigmoid behavior with time. Data from field studies included corn (Zea mays L.), tobacco (Nicotiana tabacum), and soybean (Glycine max). For the case of corn, it was shown that maximum total plant dry matter at maturity agreed very closely for the three sites. The ratio of the parameters mean time to standard deviation of the distribution was very similar for dry matter and plant nutrient accumulations, with an average of 3.6 for Wooster, OH and 3.5 for Clayton, NC. The ratio was 4.3 for water reuse at Tallahassee, FL. For tobacco, the ratio was also very similar for dry matter and plant nitrogen (N) and potassium (K), and was 3.2 at Raleigh, NC. The ratio was 2.9 for leaf area of soybeans grown at Gainesville, FL. Data for dry matter and plant nutrient accumulation followed the sigmoid shape of the model rather well. The model also produced the "hump" often observed in plant nutrient concentration during early stages of growth. The probability model suggests that for the crops studied, growth rate followed a gaussian distribution over the season, at least to first approximation.
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