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James Stahl

Researcher in Soils and Silvicultural Management at Klabin


Conserving an important heritage: the soil

In times of frank expansion of the forest-based sector and in a scenario of high land prices, the focus on soil conservation , combined with maximizing and maintaining the productive capacity of this resource, is vital for the success of new projects and continuity of projects. projects already installed.

The soil, which is the basis for production in the agricultural and forestry sectors, associated with the management practices adopted throughout the production cycles, is essential to promote and guarantee a conservationist and sustainable productive ecosystem over time. The planted forest sector has been constantly evolving over the last five decades, in the adoption and use of conservationist practices in the planting and management of eucalyptus and pine.

One of the highlights was the changes in the activities of the soil preparation process, moving from a model where all types of waste were burned during area cleaning and intensive soil preparation with plowing and harrowing in the total area to a model of minimum cultivation with subsoiling in the planting line, desiccation of the plant mass with the use of herbicides and maintenance of residues on the soil between planting lines.

These management methods and strategies were supported in the generation of scientific and technical knowledge, in partnerships with universities and national research institutes, and in the internal development and practical application of concepts by companies in the sector, in each local reality of soil and climate in that are inserted.

In addition to the change in the adopted management, the constant investments by the companies in mapping in an increasingly detailed scale of the production environments, such as digital elevation mapping of the land by LiDAR and semi-detailed soil mapping, allow the conservationist use of the soil with high degree of technification. The positive results of these practices are ensured by the growing performance in monitoring and environmental certifications that companies in the sector currently have.

In the context of Klabin, which, throughout its history, has already used the soil in parts of its areas for more than 60 years, both in the forestry units in Paraná and in Santa Catarina, the company has gained international prominence in forest management used in their areas. The company is a world reference in the use of mosaic plantations, where it combines a vast area of preserved native forests with pine and eucalyptus plantations at different ages.

This management premise of using two genres, which require different management practices and have a different production cycle, seven years for eucalyptus and sixteen years for pine, requires a great effort in strategic and operational planning, so that the best allocation occurs. of each species for each location, adjusted to the industry's supply balance and maintaining mosaic management.

This challenge of equalizing the best practices to meet these management assumptions results in a series of opportunities, among them the use of a crop rotation strategy throughout the cycles, between pine and calyptus. The alternate use of the soil, even by forest species, ends up promoting different inputs to the system, such as different biogeochemical cycling, different efficiencies in the use of soil nutrients, in the quantity and quality of harvest residues left on the soil, as well as differences in the root system, among many other characteristics related to each species.

Another point to be highlighted is that, in the process of expanding the forestry base, in the scenario of land occupation and use of new areas in different regions of the country, where, for the most part, it is a matter of converting pastures for the cultivation of eucalyptus and pinus, result, at the end of a production cycle, in important gains in environmental quality and sustainability. Recent studies by Embrapa Florestas demonstrate that pasture areas converted into eucalyptus plantations have the potential to increase the stock of carbon in the soil by 11%, in the layer from zero to 20 centimeters, evidencing the improvement in soil attributes with the entry of the tree component , even for industrial purposes.

Other important results are obtained with a set of management actions practiced during the implantation and conduction of the plantations, such as the stabilization and recovery of erosive processes present in high frequency in pasture areas, loosening of the soil, in a localized way in the plantation rows, and the construction and adaptation of an internal road network, using conservationist techniques. These practices together, when well executed, significantly reduce soil losses and help in local hydrological regulation.

The quest to maintain the productive capacity of soils already occupied by forest plantations, which are constantly subjected to highly productive genetic materials, requires that management practices, in addition to overcoming the physical constraints of the soil, promote an adequate replacement of nutrients based on the balance inputs and outputs of these system components.

Generating and making use of soil fertility information in the areas to be planted, as well as a characterization of the efficiency of nutrient use by genetic materials, allow advancing in the specific knowledge of soil-plant interaction in each region, adapting the necessary replacement dosages of nutrients, in order to make efficient use of the inputs and support the expected productivity levels.

Even if the planted forest activity has medium and long-term production cycles and that, currently, knowledge and conservation practices are already available in the sector, the generation and continuous implementation of the best practices aimed at the conservation of the soil are necessary and must be disseminated, from small to large producers. In this way, the planted forest will continue to ensure the perpetuity of one of our greatest assets, the soil.