Experiments in Goiás show that ILPF improves soil quality in the Cerrado

A study carried out by Embrapa and the Federal Institute of Goiano (IFGoiano) evaluated the impact of recently implemented Crop, Livestock and Forest Integration systems (ILPF) on the quality of the soil in the Cerrado of Goiás. The work showed improvements, compared to uncultivated pasture, through indicators of water availability and aeration (air renewal process between the soil and the atmosphere). In the second case, the increase in soil macroporosity was 50% higher than that of the reference pasture. These two elements are important as they are linked to sustainability for plant growth and microbial life underground. 

This research was carried out on two school farms in IFGoiano, one in the municipality of Morrinhos and the other in Iporá, considered representative of the southwest region of Goiás, where around 9% of the Brazilian grain harvest is produced. The ILPF systems had been implemented for one to two years, that is, they were in their infancy, and included eucalyptus and native trees (such as baru and angico) with the cultivation, between rows, of soybeans, corn and brachiaria. Dairy cows were grazed in the forage area while electric fences protected the growing trees. For comparison purposes, reference areas under pastures that had not been cultivated for more than 30 years were taken into account.  

The researchers collected soil samples in the experimental areas in seven different soil profile layers, at a depth of up to one meter. Collecting soil samples up to one meter in areas with a tree component is important, due to the reach of tree roots in production systems. The samples underwent laboratory procedures, including statistical analysis of indicators related to the porosity and physical-water properties of the soil.

Soils with greater water retention and aeration

The results obtained were that, in Morrinhos and Iporá, ILPF increased the moisture retained by the soil, between 0,1 millimeter and 0,7 millimeter per centimeter of soil, compared to the uncultivated pasture area that was the reference. This apparently small amount of water can be crucial for the survival of plants during long periods of drought and high temperatures. In Iporá, where baru and eucalyptus were cultivated in the ILPF system, the soil also had a greater aeration capacity compared to the reference area. The experiment considered the most superficial layer of the soil (up to 30 centimeters deep), where these differences were most significant. 

Embrapa Arroz e Feijão (GO) researcher Márcia Carvalho was one of the coordinators of this work. It explains the context in which these results were obtained and the difference in the effects of the ILPF system measured in each of the experiments.

“In the case of Morrinhos, the farm’s soil is classified as clayey Oxisol. Under the conditions under which the ILPF system was conducted, higher CAD (soil available water capacity) values ​​were measured than in the reference pasture. This can be attributed to the greater volume of micropores responsible for water retention and storage in the soil. Oxisols are naturally rich in aggregates and micropores, but the ILPF system contributed to the increase in these water storage sites in relation to uncultivated pasture”, says Carvalho.

In Iporá, she notes that “the experiment took place in a Cambisol, with emphasis on the CAS indicator (soil aeration capacity), which measures the number of pores responsible for the exchange of oxygen and carbon dioxide between the atmosphere and the soil. CAS is directly proportional to macroporosity, which increased by 50% in the ILPF system in relation to the reference pasture soil. Higher CAS means greater capacity to meet the respiratory demand of roots and microorganisms, which is important in these soils which, despite being sandy, may have impeded drainage due to the high level of the water table and the formation of canga stone, a solid material formed by minerals. ”, he adds.

The dynamics of root and microorganism life in the soil are linked to a series of processes involving soil health: fertility, nutrient absorption by plants and agricultural sustainability, in addition to ecological roles such as nutrient cycling and decomposition of organic matter, related to the capture of carbon and nitrogen from the atmosphere.

The researcher highlights that the experiments conducted to evaluate the short-term impact of ILPF systems on the physical-water characteristics of typical soils in the Center-West region of Brazil are a way of monitoring differences in the evolution of soil quality, since initial phase of implementing integration between crops, forages and tree species. Therefore, she considers it important to continue monitoring over time.         

Biodiversity contributes to mitigating the effects of climate change

The knowledge surrounding the ILPF presupposes that integration systems allow sustainable models of grain, forage, meat and milk production, while increasing income in the field. ILPF enables the recovery of degraded soils and the preservation of natural resources, such as water. It also reduces the pressure to open new areas in rural areas.

In addition to ILPF, there are other types of integration systems that contribute to more sustainable production. According to Carvalho, agroforestry systems are also a type of agricultural production, in which the introduction of trees helps to regulate the local temperature and maintain humidity and water in the soil, “essential factors for coping with the long period of drought and increasingly frequent heat waves in the Cerrado”, he states.

The researcher also cites the so-called agroecological and participatory systems as sustainable production options, as they simultaneously enable the construction and recovery of knowledge and technologies for adaptation at the local community level and, therefore, partnerships and collective action are a mark of diversity in these systems. production. In this case, “economic and ecological costs and gains go hand in hand, in the sense that there is always a trade-off to be made”, she adds.

She further explains that agroecological production systems are aligned with the sustainable development goals of the United Nations (UN) and the 2030 Agenda, through the search for more sustainable forms of production and consumption, combating hunger and combating climate change. . Regarding the latter, Carvalho mentions that biodiversity, perpetuity and stability of production in agroecological systems over time are key strategies for facing uncertainties generated by climate extremes, in addition to contributing to increasing food security.

Regarding the scope of climate change, she considers that “they are natural and biophysical responses of planet Earth to human activities. Deforestation for cultivation, the burning of fossil fuels for transportation, mechanization and the production of inputs or industrialized consumer goods are important sources of greenhouse gas (GHG) emissions. Global warming is inevitable and irreversible on a secular time scale, but we can adapt to the effects of climate change at regional and local levels. We need to implement strategies based on knowledge and technologies from agronomic research and experience, especially in tropical countries like Brazil, where agriculture can be an ally in food production and also quality of life”, concludes the researcher.