Soil tillage and precision agriculture - A theoretical case study for soilerosion control in Brazilian sugar cane production

The variability of most soil properties is expressed at small scales. Agron omic practices and treatments are usually designed to be extremely uniform at this scale. The contradiction of applying uniform treatments to variable conditions is the key issue of precision agriculture. Traditionally, preci sion agriculture means variable application of material inputs such as fert ilizers, pesticides and amendments. Although the practical results expresse d in terms of economic feasibility or advantages for crop production are co ntroversial, the basic concepts of precision agriculture applied to other i nputs, such as time and labor, have theoretical advantages and may have a g reater possibility to develop into profitable technology. This paper descri bes a theoretical example based on sugar cane production in a 77 ha watersh ed located in the southeastern part of Brazil. Precision agriculture concep ts focusing on P-fertilizer inputs were compared with optimization of mecha nical operations such as planting and harvesting. Measurable advantages for precision agriculture compared with traditional treatments were observed f or mechanical operation efficiency but not for P-fertilizer. Recent practic al experiences in Brazilian sugar cane production of treating soil conserva tion as spatially variable to gain efficiency in mechanical operations is a clear example of the economic feasibility of implementing precision agricu lture by increasing efficiency instead of decreasing materials or increasin g yields. (C) 2001 Elseviel Science B.V. All rights reserved.