Agricultural productivity in the tropics is affected first by soil acidity and related factors (pH, base saturation, potential acidity, nutrient availability). Liming is a well-known but irregularly used beneficial practice to correct soil acidity in annual cropping systems. For perennial crops such as fruit orchards, lime incorporation is more difficult to implement as a result of length of the rotation and lack of scientific support. The lime neutralizes exchangeable aluminum, increases pH and supplies Ca and Mg to the growing roots. Because lime moves slowly in the soil, it must be incorporated deeply and uniformly before establishing the orchard to enhance soil exploration by the root system. Compared to fertilizers and pesticides liming can impact soil properties during several consecutive seasons and its effect depends on soil type, contact with the soil as lime is incorporated, fruit species and liming material. In general, the effect of larger lime particles is long-lasting. In orchards, lime is applied before establishment using lime materials of varying grain sizes. However, the relationship between grain size and long-time effect has been little studied because long-time research is expensive. With increasing application of ammonium-based N fertilizers in high-yielding orchards, soil acidity increases as a result of nitrification. Farmers presently apply lime superficially to established orchards in absence of sufficient experimentation on possible damage to the root system, root infection, pest blooms and soil compaction. The aim of this chapter is to quantify the effect of liming experiments on soil fertility, mineral nutrition and yield of tropical orchards in Brazil during establishment and full production cycles and determine the economic lime rate optimum for a long-term effect.
Acidity Correction; Limestone; Deploying Orchard
