**3. Mechanization in crops with high coffee shrub population density**

In coffee plantations, mechanization has emerged as an alternative in reducing production costs, operating income, and reducing labor hardness. However, for the preservation of natural resources (soil and water), soil and machinery management becomes essential to minimize the effects of anthropogenic actions on the soil. Within these aspects the coffee farmers can reduce the axle load and the contact pressure of the tires with the soil and use management systems that contribute to the deposition of organic matter, as soils with greater aggregation support more load and the organic matter relieves stress exercised by agricultural machinery.

Soil stress exerted by tires or tracks of machines on soil interface can be assessed according to machine characteristics and soil attributes [15]. These authors modelled soil stress through the software Tyres/Tracks and Soil Compaction (TASC) version 3.0 [16].

TASC version 1.0 was used for the first time in Brazil in a long-term weed control method experiment to assess the effects of weed control on soil loadbearing capacity and the impact of a coffee tractor on soil stresses [17]. In this study, a coffee tractor Valmet®, model 68, with a power rating of 44.9 kW (61 hp), a total weight of 38,245 N (3900 kg), front tires of 6.16 at inflation pressure 172 kPa, wheel mass of 683 kg and rear tires of 12.4 R28 at inflation pressure 124 kPa, and wheel mass of 1.365 kg was used for coffee management and mechanical weed control.

The contact area at soil-tire interfaces ranged from 0.0381 m<sup>2</sup> for the front tire to 0.1328 m<sup>2</sup> for the rear tire 12.4 R28 [17]. The ground average contact pressure at soil-tire interface ranged from 101 kPa to 176 kPa, with the highest occurring for the front tires. As highlighted by Guimarães Júnnyor et al. [15], the ground average contact pressure depends on the tire type, tire structure, tire sizes, wheel load, inflation pressure, and soil stiffness.

**49**

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

The State of Paraná (**Figure 1**) is located between the coordinates 22°30′ and 26°30′ S latitude and 48° and 55°W longitude within a region of climatic transition, from north to south, with regional and local variation due to altitude and topography. However, the recommended area to coffee cultivation in the State of Paraná [18] is located between the coordinates of the southern latitudes 22°51′50″, 24°76′70″ west longitude, and 49°55′30″ to 54°34′20″ from Greenwich

High coffee shrub population density system (higher than 5000 shrubs per hectare) was developed in the State of Paraná by the Agronomic Institute of Paraná (IAPAR) to improve coffee yields and to provide economic benefits to coffee farmers; soil and water conservation also helps coffee shrubs after frost

In Londrina in the State of Paraná, in an experiment conducted between 1976 and 1981 to determine the effects of spacing between plants in the row (4 m × 1 m and 4 m × 2 m), Siqueira et al. [19] concluded that irrespective of coffee cultivars (Catuaí Vermelho LCH 2077-2-5-81 and Acaiá LCP 474-4) or hybrid Icatu H 4782-7 AMBR (*Coffee arabica* vs *Coffea canephora* Pierre) the coffee yields per area increased with decreases of spacing between plants 2 m

In addition to crop response, coffee shrub population density system promotes

Soil correction by liming and/or gypsum has a significant influence on the soil

Liming by applying limestone–calcium carbonate [Ca(CO3)2] or magnesium carbonate [Mg(CO3)2] is the soil management practice used to correct excessive soil acidity. In addition to correcting acidity, lime application in soils is able to provide calcium and magnesium, provide nutrients, and neutralize excess aluminum and

Gypsum applied on the surface of soil columns with dimensions of 0.6 m in height by 0.3 m in diameter provided increases in Ca contents and decrease in exchangeable Al contents, consequently favoring the root growth of deep coffee seedlings [27]. These authors also pointed out that the superficial application of the gypsum–CaSO4–was more efficient than CaCO3 incorporated at 0.3 m depth due to the higher root growth in depth as a result of the exchangeable calcium increase and

In the long term, both liming and gypsum can contribute to reducing the risks of erosion in coffee-cultivated LVdf, especially under conditions without green cover between rows and with uncovered soil. In a typical Distroferric Red Latosol (LVdf) (Rhodic Hapludox), very clayey texture cultivated with coffee shrubs in Londrina, Northern State of Paraná, liming and gypsum had positive effects on soil aggregation and consequently on the water infiltration rate in the soil profile 2 years after

On the other hand, the short-term incubation studies (3 months after limestone application), using samples from an LVdf from Londrina, Castro Filho and Logan [9], found that the aggregates were stable in water up to the pH value in CaCl2 equal to 5.7. On the other hand, when pH values exceeded 5.7, they reduced the stability of

improvements in chemical, physical, and biological soil attributes [20].

**4. Liming and gypsum on clay fraction flocculation and soil particle** 

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

(**Figure 1**).

damage.

and 1 m [19].

**aggregation**

physical and water properties [9, 21–26].

soil manganese that are toxic to plants [20, 22].

aluminum reduction in the subsurface ground.

corrective application [21].

the aggregates in water.

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

The State of Paraná (**Figure 1**) is located between the coordinates 22°30′ and 26°30′ S latitude and 48° and 55°W longitude within a region of climatic transition, from north to south, with regional and local variation due to altitude and topography. However, the recommended area to coffee cultivation in the State of Paraná [18] is located between the coordinates of the southern latitudes 22°51′50″, 24°76′70″ west longitude, and 49°55′30″ to 54°34′20″ from Greenwich (**Figure 1**).

High coffee shrub population density system (higher than 5000 shrubs per hectare) was developed in the State of Paraná by the Agronomic Institute of Paraná (IAPAR) to improve coffee yields and to provide economic benefits to coffee farmers; soil and water conservation also helps coffee shrubs after frost damage.

In Londrina in the State of Paraná, in an experiment conducted between 1976 and 1981 to determine the effects of spacing between plants in the row (4 m × 1 m and 4 m × 2 m), Siqueira et al. [19] concluded that irrespective of coffee cultivars (Catuaí Vermelho LCH 2077-2-5-81 and Acaiá LCP 474-4) or hybrid Icatu H 4782-7 AMBR (*Coffee arabica* vs *Coffea canephora* Pierre) the coffee yields per area increased with decreases of spacing between plants 2 m and 1 m [19].

In addition to crop response, coffee shrub population density system promotes improvements in chemical, physical, and biological soil attributes [20].
