**1. Introduction**

Crop production is more problematic in tropical and subtropical climatic conditions than in temperate humid climates [1]. These authors highlighted that many cultivated plants derive from regions which are ecologically different from their present region of production. When competing with weeds which have become properly adapted to their habitat, these crops cannot survive without protection and assistance from the farmer.

Brazil is the greatest exporter of coffee and second consumer of the product in the world. Currently, the land area cultivated with coffee is 1.84 million of hectares, the total 1.47 million of hectare (≈80%) being cultivated with *Coffea arabica* L. species and 373.33 mil hectares (≈20%) with *Coffea canephora* Pierre (Secretary of Agricultural Policy in the Ministry of Agriculture, Livestock and Food Supply— MAPA, 2019).

In the state of Paraná, most coffee plants are cultivated in high coffee population density system (>5000 plants per hectare) which guarantees the coffee farmers higher productivity by hectare [2] in soils derived from basalt with high iron content (Fe2O3 higher than 18 dag kg<sup>−</sup><sup>1</sup> ). In these soils, the workability is easier, and the drainage is usually very good [3]. On the other hand, in the high coffee population density, spacing between coffee rows is 2–3.2 m and 0.5–0.75 m between the plants in the lines, which compromises the mechanization of operations to management and harvest.

Soil slope is another important factor that compromises the mechanical operations and coffee management besides coffee planting spacing. In a previous study done in the climatic zoning of the State of Paraná for the cultivation of coffee (**Figure 1**), Höfig and Araujo-Junior [3] showed that 89% of the land area are not limited to mechanization by the criterion of soil slope classes.

Considering mesoregions of the State of Paraná, the northwest has the smallest area with a slope higher than 20% and therefore the greatest potential for mechanization of coffee plantations. On the other hand, in the Pioneer

#### **Figure 1.**

*Map of the State of Paraná with slope classes and potential for mechanization in the area with climatic zoning to cultivate coffee. Source: Höfig and Araujo-Junior [3].*

**47**

dispersion.

*Soil Electrochemical and Physical Properties in Coffee Crops in the State of Paraná, Brazil*

Northern mesoregion, which currently has about 37% of coffee plantations in the State of Paraná and has great technological potential due to edaphoclimatic characteristics for coffee cultivation, 10% of the area is not recommended for mechanization based on soil slope classes, which represents an area of 160,000

Besides mechanization, the addition of soil amendments like limestone and gypsum and weed control methods affects the behavior of soil properties. In long-term experiments conducted in different coffee regions of Brazil, the effects of weed

Weeds when properly managed in both row and interrow areas can become allied with the coffee farmer without compromising crop yield. On the other hand, when the weed is constantly controlled with pre-emergence herbicide, soil surface is exposed to direct raindrop impact which can form soil crusting that makes water infiltration more difficult. As a consequence of surface soil crusting, runoff is

Research results have shown that weed management modifies soil resistance to compaction and can minimize damage caused by machine traffic on the soil as well as assisting soil and water management and conservation by providing benefits for

In this chapter of the book, we presented that soil physical and mechanical properties are essential to the assessment of the effect of anthropogenic activities on natural resources and may help coffee farmers to obtain an optimum soil environment for plant growth. Due to that, this chapter characterizes the soil physical

Soil physical properties are essential to comprehension of the behavior of the soil when submitted to mechanization. Among the physical properties, the water content in the soil profile determines the reaction to tillage, and soil moisture is the most important for soil-machine interactions, since it controls the consistency of the soil [4] and governs the amount of soil deformation when subjected to external

In aerated soils, pH is considered to control available nutrients to plants. Also, pH is related to soil charges and is a key property expanding double layers of colloids. Points of zero charge (PZC) are pH values associated with specific conditions imposed on one or more surface charge densities of an electrified interfacial region between a soil solution and soil solid phase [6]. Point of zero charge indicates the pH at which the net surface charge on variable charge

The surface charge density is the most important physical characteristic of an electrified interface. It can be defined as the number of coulombs per square meter borne by surface functional groups, and it depends in sign and magnitude on the composition of the soil solution and structure of the solid phase to which the

According to these authors, ∆pH is the electrochemical soil properties that most affect the dispersion. When ∆pH tends to zero, charges are balanced with less

) through Eq. (1).

PZC = 2 pHKCl − pHH2O (1)

PZC was estimated from pH-H2O and pH-KCl (1 mol L<sup>−</sup><sup>1</sup>

properties in coffee crops in the State of Paraná, Southern Brazil.

**2. Soil electrochemical and physical properties in coffee crops**

*DOI: http://dx.doi.org/10.5772/intechopen.91352*

control methods on soil attributes have been proven.

increased, and hydric soil erosion must be a problem.

accelerated water erosion.

pressure [5].

surface is zero [7].

functional groups are bound [6].

hectares.

#### *Soil Electrochemical and Physical Properties in Coffee Crops in the State of Paraná, Brazil DOI: http://dx.doi.org/10.5772/intechopen.91352*

Northern mesoregion, which currently has about 37% of coffee plantations in the State of Paraná and has great technological potential due to edaphoclimatic characteristics for coffee cultivation, 10% of the area is not recommended for mechanization based on soil slope classes, which represents an area of 160,000 hectares.

Besides mechanization, the addition of soil amendments like limestone and gypsum and weed control methods affects the behavior of soil properties. In long-term experiments conducted in different coffee regions of Brazil, the effects of weed control methods on soil attributes have been proven.

Weeds when properly managed in both row and interrow areas can become allied with the coffee farmer without compromising crop yield. On the other hand, when the weed is constantly controlled with pre-emergence herbicide, soil surface is exposed to direct raindrop impact which can form soil crusting that makes water infiltration more difficult. As a consequence of surface soil crusting, runoff is increased, and hydric soil erosion must be a problem.

Research results have shown that weed management modifies soil resistance to compaction and can minimize damage caused by machine traffic on the soil as well as assisting soil and water management and conservation by providing benefits for accelerated water erosion.

In this chapter of the book, we presented that soil physical and mechanical properties are essential to the assessment of the effect of anthropogenic activities on natural resources and may help coffee farmers to obtain an optimum soil environment for plant growth. Due to that, this chapter characterizes the soil physical properties in coffee crops in the State of Paraná, Southern Brazil.
