Integrated systems increase grain production in Matopiba

A study carried out by researchers from Embrapa Meio-Norte (PI) concluded that the adoption of integrated crop-livestock systems is the most appropriate strategy to provide sustainability to grain production in the Matopiba region - an area that encompasses parts of Maranhão, Tocantins, Piauí and Bahia.

The research evaluated the dynamics of soil organic carbon and carbon and nitrogen stocks under various cropping arrangements: Crop-Livestock-Forest Integration (CLFI); Crop-Livestock Integration (CLFI) under no-tillage; Crop-Livestock Integration (CLFI) with recent soil plowing; pasture; and native Cerrado vegetation. The two CLFI options and pasture presented higher carbon and nitrogen stocks. Crop-Livestock Integration also guaranteed a greater quantity of humic substances, which are essential for fertility, influencing water and nutrient retention, soil structure, and microbial activity.

Embrapa researcher Edvaldo Sagrilo states that, based on the data from this research, in order to obtain a greater carbon stock in the soil, it is essential that the producer manages the adopted system well. Both a livestock farmer who implements a well-managed pasture and a farmer who invests in a well-conducted ILP system will benefit from this environmental benefit.

Advantages of storing carbon in the soil

The researcher emphasizes that adopting systems that improve soil carbon storage brings several advantages. “Firstly, the farmer benefits from a financial standpoint, with improved soil fertility and, consequently, a sustainable increase in crop productivity. These systems also optimize the use of inputs such as fertilizers, as they reduce losses of this input to the environment,” reports the scientist.

Furthermore, Sagrilo explains that increasing soil carbon stocks means fewer emissions into the atmosphere, which helps mitigate global warming and benefits society as a whole. Finally, he points out that, with the carbon market regulation process, increasing soil stocks could result in payment for environmental services (carbon credits) to producers in the future.

The ability of soils to act as a sink (absorbing and storing carbon from the atmosphere) or as a source (releasing carbon to the atmosphere) depends on the balance between carbon inputs and outputs and is related to land or crop management.

How the research was done

The research team believes that land use systems affect soil organic carbon stocks differently, with more stable fractions (which take longer to decompose) being obtained in integrated systems such as ILP and ICLF, and that integrated systems established over the long term can increase carbon and nitrogen stocks compared to native Cerrado vegetation. To study these hypotheses, the group compared carbon and nitrogen stocks and the dynamics of soil carbon fractions under pasture conditions, integrated management systems (ILP and ICLF), and natural vegetation. 

The research was carried out in the municipality of São Raimundo das Mangabeiras (MA), in areas with similar climate and soil characteristics, comparing native Cerrado areas close to other cropping systems. The following were observed: an ILPF system cultivated with Brachiaria for 13 years; an ILP system cultivated for 16 years with corn intercropped with Brachiaria and subsequently soybean with millet; an ILP system with superficial soil preparation cultivated in the same way, with subsequent deep soil turnover for intercropping corn with Marandu grass; and pasture cultivated for 15 years for beef production. Approximately one hectare of each management system was chosen for soil sampling, carried out at four different depths.

The results of the analyses indicated higher carbon stocks in ILP systems and pasture, at all soil depths. The ILPF production system and native Cerrado areas presented the lowest stocks at all depths.

 The implementation of ILP and pasture systems in native Cerrado areas considerably increased the stocks of organic carbon and total nitrogen in the soil. The carbon values ​​in ILP with direct planting, ILP with recent plowing of the soil, and pasture areas increased by 84%, 108% and 66%, respectively.

The researchers attribute this result to two factors. First, the study was conducted in an area of ​​low native vegetation with patches of pasture and sparse trees, which generally have low natural fertility and plants with little capacity to produce biomass, characteristics of the region. Thus, the ILP and pasture systems with Urochloa brizantha provided the input of a consistent volume of organic waste. Another factor pointed out is the time of adoption of these conservation management systems over the years, approximately 16 years. The literature indicates that these systems have greater potential for carbon storage after more than a decade of adoption.

Fernando Devicari, a soybean producer in the municipality of Brejo (MA), adopted the ILP system 15 years ago and the ILPF nine years ago. “The reason we started with this system is that what we were doing wasn’t working. We have a very serious problem with organic matter here in the region. The main crop was corn and we evaluated the organic matter year after year and kept reducing it. Here, the rainy season is very, very hot, very humid, so this straw degraded very quickly and then you made good straw like this to increase the organic matter in the soil, you would measure it in the next harvest and there was less than in the previous harvest. The idea was to come up with another system that was more robust in terms of organic matter and we found the crop-livestock integration.” 

Today, the corn and grass consortium occupies approximately 20% of Devicari’s property annually, which has led him to notice improvements in soil quality. “When we assess the soil in the areas where we first started, we have twice as much organic matter. So, in ILP areas, we doubled the amount of organic matter.” Devicari also states that, as a result of this change, he harvests 7,8 more bags of soybeans per hectare. 

Sagrilo explains that although the results presented were obtained in a specific location and condition in Matopiba, the concept of sustainability embedded in the techniques used can be extrapolated to other areas of the Cerrado. “In fact, similar studies have been developed in other regions of Matopiba and outside it, and have demonstrated a similar trend of results, in which the adoption of integrated systems results in improvements in indicators of productive and environmental sustainability, compared to conventional systems.”