Variable lime application based on within-field variation in soil pH
2003
Zaman, Q. (University of Agriculture, Faisalabad (Pakistan). Dept. of Farm Machinery and Power) | Shiel, R.S. | Schumann, A.W.
The variability of soil pH, texture and organic matter was studied with the prospects of varying application rate of lime by precision farming techniques. Soil pH varied greatly across the uniformly managed field at the farm of University of Newcastle, England. Soil samples were taken on a regular grid of 20m x 40m using differential Global Positioning System (DGPS). The spatial analysis showed that the range was large, resulting in maps having a uniform pH. The large areas of uniform pH would allow differential application of liming material. A uniform application of lime, based on an average pH for the entire field was shown to be less effective than spatially targeted applications. Only 9% of the field was at the mean pH 5.9 (plus minus 0.1), which would be limed using the conventional approach, required no liming. 35 % of the total area required 0.5 t/ha more than the recommended rate and 56% require less than 0.5 t/ha less. The results suggest that variable application should become common practice to increase the agronomic and environmental efficiency.
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