Calculation of K uptake by two crops grown under field conditions using a mechanistic nodel
2011
El-dessougi, H.I., University of Khartoum, Khartoum (Sudan). Faculty of Agriculture, Dept. of Agronomy | Claassen, N., University of Goettingen, Goettingen Germany, (Germany). Institute of Agricultural Chemistry | Steingrobe, B., University of Goettingen, Goettingen Germany, (Germany). Institute of Agricultural Chemistry
: The objective of this study was to compare simulated and actual potassium uptake by two crops, using soil and plant parameters obtained from a field experiment conducted in 2003, in Bavaria, southern Germany. Sugar beet (Beta vulgaris L. cv. Kawetina) and wheat (Triticum aestivum L.cv. Star) were grown on a sandy clay loam in the field. The K transport in soil and uptake by the plants were simulated by a mechanistic model which encompasses uptake by root hairs as well. A sensitivity analysis was carried out in an attempt to understand the significance of single soil and plant parameters for nutrient uptake. The simulation model calculated only 34 % of the measured sugar beet uptake throughout the growing period. The lowest calculated K influx (only 9 % of measured value) corresponded to the period June 24th -July 8th of highest actual uptake. Sensitivity analysis showed that, under low K concentrations, K concentration in the soil solution was the most important factor controlling K uptake, especially for sugar beet. This indicates that roots may have increased the K concentration in soil solution by chemical mobilization. Research is needed to understand the mechanism by which this is achieved
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