**4. Considerations on fruit growing areas and fructiferous plants**

By comparison with other regions of the world, Brazil is endowed with adequate character‐ istics of soil, climate, water availability and diversity of fruit species that give it great poten‐ tial as a fruit producer and exporter.

These favorable conditions for the development of fruit growing regions expand agroindus‐ trial activity and boost exports, not only because of the nutritive value of fruits, but also be‐ cause of the perspective they represent to increase farm production. Besides this, cultivation of perennial species, as are most fructiferous plants, triggers the occupation of areas with soils classified unsuitable for the majority of annual crops.

Despite those advantages, there is still a lack of information on the correct management of soil fertility, the choice of inputs and the nutritional needs of fruit-bearing plants, prevent‐ ing Brazil from realizing its full agribusiness potential.

Because fruit orchards are perrenials and trees' roots remain practically restricted to the same soil space for many years, it is important to incorporate homogeneous amounts of limestone to deep levels before planting so the root system can develop adequately for effi‐ cient uptake of water and nutrients. This enhances the development and nutritional status of the plants with less need for fertilizers, thus improving the cost-benefit ratio of inputs and boosting crop productivity. In producing orchards, repeatedly applied high doses of nitro‐ gen over restricted areas (projection of the tree crowns) aggravate the problem of soil acidi‐ ty, hence requiring regular soil chemical analysis.

Fruit growing is an important activity in most Brazilian regions, especially those covered with latosols (oxisols) and argisols (ultisols), which are generally deep and permeable, hence providing ideal conditions for perennial crops that produce a broad and well developed root system. Nevertheless, these soils have a strong acid reaction and are low in nutrients, so they need liming and fertilization.

*GN* (*kg h a* <sup>−</sup><sup>1</sup>

where:

178 Soil Fertility

)= 6 × *clay*

GN is the need for gypsum, in kg ha-1; and

For diagnosing the nutritional status of plants, leaf analysis is the most efficient technique, but also the one where errors occur most frequently. Each plant species has its own sam‐ pling procedure. Thus, the leaves to be collected and the time of the year are critical for suc‐ cessful diagnosis of the plant nutritional status. In the case of fruit trees, such as the guava tree, the third pair of leaves should be collected from each plant, with 25 pairs being collect‐ ed from each homogeneous plot. This should be done at the time of full flowering [21]. These leaves should be immediately taken to the laboratory for washing, drying, grinding and analysis. The next step is to interpret the results, based on studies conducted under field

In summary, when performed correctly, analysis of soil and leaf samples can allow making recommendations on liming and fertilization to improve fruit yield and quality, and hence

By comparison with other regions of the world, Brazil is endowed with adequate character‐ istics of soil, climate, water availability and diversity of fruit species that give it great poten‐

These favorable conditions for the development of fruit growing regions expand agroindus‐ trial activity and boost exports, not only because of the nutritive value of fruits, but also be‐ cause of the perspective they represent to increase farm production. Besides this, cultivation of perennial species, as are most fructiferous plants, triggers the occupation of areas with

Despite those advantages, there is still a lack of information on the correct management of soil fertility, the choice of inputs and the nutritional needs of fruit-bearing plants, prevent‐

Because fruit orchards are perrenials and trees' roots remain practically restricted to the same soil space for many years, it is important to incorporate homogeneous amounts of limestone to deep levels before planting so the root system can develop adequately for effi‐ cient uptake of water and nutrients. This enhances the development and nutritional status of the plants with less need for fertilizers, thus improving the cost-benefit ratio of inputs and boosting crop productivity. In producing orchards, repeatedly applied high doses of nitro‐ gen over restricted areas (projection of the tree crowns) aggravate the problem of soil acidi‐

**4. Considerations on fruit growing areas and fructiferous plants**

Clay is the soil clay content, in g kg-1.

conditions in high-yielding orchards.

increase the profits of fruit growers.

tial as a fruit producer and exporter.

soils classified unsuitable for the majority of annual crops.

ing Brazil from realizing its full agribusiness potential.

ty, hence requiring regular soil chemical analysis.

Roots do not develop satisfactorily in highly acid soils. Among the acidity factors, alumi‐ num toxicity and calcium deficiency are indicated as the most relevant restrictions to root growth. Regarding acidity correction with application of limestone at soil surface without no incorporation, research reported low movement of the lime to deeper layers, depending on the dose applied, the time elapsed and the fertilization regime.

Knowledge to support adequate management of soil fertility and plant nutrition is particu‐ larly important for fruit growing systems, given the influence these production factors on the qualities of fruits, such as color, size, taste, aroma and appearance. Meeting plants' nu‐ trient needs is one of the key factors for the success of this activity, because besides affecting yield and quality, adequate nutrition increases plant growth, tolerance to pests and diseases and postharvest longevity. On the one hand, the demand of this group of plants for mineral elements is relatively high, while on the other tropical soils in which they are normally culti‐ vated are low in nutrients, making it imperative to apply nearly all the nutrients necessary for their full development. This leads to the use of high amounts of fertilizers [21, 11] and corrective measures [12, 13, 22] in orchards and requires technical competence for economi‐ cally rational use of these inputs. For Brazilian conditions, the analyses can be interpreted with the help of the Fert-Goiaba software [23].

Information on the effects of liming on the development and nutritional status of fructifer‐ ous plants is very limited in the literature despite the widespread scientific recognition of the importance of acidity correction. Much more attention has been paid to these aspects in annual cropping systems, but those findings cannot be transferred directly to perennial plants because the latter do not react the same way to liming and fertilization for a various reasons as follows [24]:


**d.** Liming and fertilization of orchards are determinant not only in the current growing season, but also for harvests to come because the inputs applied at one time will also supply the pending production by promoting the formation of new fruit-bearing shoots and building up nutrient reserves in the roots and the aboveground biomass for the fol‐ lowing seasons.

**Soil nutrient**

**2001 2002 2003 2004 2005 Ca Mg Ca Mg Ca Mg Ca Mg Ca Mg**

Soil Acidity and Liming in Tropical Fruit Orchards

http://dx.doi.org/10.5772/53345

181

Ca (R) 0.91\* 0.99\*\* 0.95\* ns ns Ca (B) 0.94\* 0.96\*\* 0.99\* 0.97\* 0.93\* Mg (R) ns 0.79\* ns ns ns Mg (B) ns 0.92\* 0.97\* 0.81\* 0.84\* R: in tree rows; B: between tree rows. \*\*, \* and ns: significant at p < 0.01, p < 0.05 and not significant, re‐

**Table 1.** Correlation coefficients between Ca and Mg concentrations in the soil (0–20 cm) between and in the tree

**Figure 1.** Effect of applying limestone on guava fruit yield for yearly harvests (a) and cumulated production (b).

spectively. The values are means of four repetitions each year.

rows and leaf Ca and Mg concentrations in guava trees over the experimental period

For a long time some fruit trees, especially those native to tropical regions like guava and carambola, were considered to be rustic plants, so their development was thought to be in‐ dependent of edaphoclimatic conditions as is still felt today about pastures. However, it is not possible to imagine that a soil can be exploited by a crop indefinitely without replenish‐ ing the nutrient reserves or correcting the acidity. However, due to the characteristics of per‐ ennial fruit-bearing plants, the difficulties of conducting long-term experiments under present research funding support tend to discourage researchers.
