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Brazil currently uses 8% of all fertilizer produced in the world. The country is in fourth place among the largest consumers, behind only China, India and the United States. However, there is a big problem: national production is very small. To meet agricultural demand, more than 85% of nutrient sources are imported. Furthermore, the efficiency of fertilizer use is often low. On average, around 40 to 50% of Nitrogen (N), 20 to 30% of P (Phosphorus) and 70% of K (Potassium) are used. And these inputs can represent more than 40% of the production costs of some crops.
In a complicated international situation, such as the one we have been experiencing since the end of 2021, with problems in distribution logistics and Russia's war with Ukraine, there has been an increase in the price of these products. Variation in prices and uncertainty in supply have been a major concern for producers. So, we are in a very complex situation, as an expensive input is imported, and it is often not used in the best way.
There are several ways to increase the efficiency of nutrient use in the field. Many technologies are available to the producer. Next, some technological solutions are presented that can help improve the application of good practices and contribute to high productivity in Brazilian agriculture in a rational and sustainable way.
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Soil analysis
Soil chemical analysis is essential to assess soil fertility. By interpreting the results, it is possible to carry out chemical soil management in an efficient and economical way. Associated with physical analyzes (soil density, texture, for example), with the most accessible biological analyzes (enzyme activities) today, it is possible to carry out a complete and very informative diagnosis of the soil condition. The results of the chemical analysis determine the stock of nutrients and limiting chemical elements before planting, enabling the correct recommendation for liming and fertilization, as well as periodically monitoring and evaluating the balance of nutrients in the soil. Furthermore, the nutrient balance in the soil-plant system can be considered an indicator of the sustainability of agricultural land use.
All liming and fertilization recommendations must be made based on the results of chemical analyzes on samples collected in different production systems. Thus, avoiding the use of fixed amounts of limestone and fertilizer formulations, which, if used without criteria, can lead to “imbalances”, applying underdoses or in excess.
Increased efficiency fertilizers
One of the alternatives to reduce the potential for loss and environmental impact is the use of nutrient sources with increased efficiency. This category of new inputs or special fertilizers can be slow-release fertilizers, which release nutrients more slowly than common fertilizer, and controlled-release fertilizers, which have their release rates and periods altered. Both feature technologies that alter release patterns, delaying the solubilization of nutrients, compared to conventional sources.
These new inputs can increase the efficiency of nutrient use, by reducing losses due to leaching (N and K), volatilization (N), denitrification (N) and fixation (P), and thus increasing absorption by plants through the supply gradually, according to crop demand. Ideally, the release should be modulated and follow the plant's growth rate, in order to meet its nutritional needs, which change throughout the growth and production cycle.
precision agriculture
Several research results and the practical experience of farmers have indicated that the combination of agronomic knowledge with digital technologies, such as precision agriculture (PA), can also help to improve the efficiency of fertilizer use, as the management of crop fertility soil, without taking into account spatial variation within production areas, can directly affect productivity and environmental quality. This is because knowledge of the spatial variability of soil properties is essential for establishing homogeneous management zones, and for the localized and variable-rate application of lime and fertilizers, thus contributing to the rational use of fertilizers.
AP begins with data collection, analysis and interpretation of information, generation of recommendations for intervention in the field and harvest, it is a chain of knowledge, uniting machines, equipment, sensors with information technologies to support agricultural management. Therefore, the generation of thematic maps is essential to define the most efficient management strategies, in particular, the rational use of inputs.
The use of AP as in georeferenced soil sampling and variable rate application of inputs has been used in production areas, especially in large soybean, corn, sugar cane and cotton crops. There are results for several other crops and for pastures, showing that it is possible to map and evaluate the spatial variability of soil properties and recommend liming and fertilizer application based on these maps. This helps to increase the efficiency of use and optimize resources, applying the right dose, in the right place and at the most appropriate time.
But for AP to advance even further, mappings need to be reduced in cost, more robust and accurate. To make this possible, new methods, sensors and equipment are being developed, tested and used in the field. AP will be increasingly driven by the rapid development of the internet of things (IoT), big data, cloud computing and artificial intelligence (AI), which, working with the integration of interfaces and technologies, will overlap and encompass AP with the management information systems in agriculture.
Integrated systems
Conservation agriculture includes a set of management practices based on direct planting or minimal soil disturbance, maintaining permanent soil cover with plant material and crop diversification. The adoption of these conservation practices increases the input of organic matter into the soil and changes its decomposition rates, favoring the aggregation of particles and promoting soil structure. Crop rotation and soil cover increase water infiltration and retention, regulate temperature, stimulate biological activity and reduce pressure from invasive plants. With the reduction of soil disturbance and preservation of its structure, there is an increase in water-conducting pores. As a consequence, there is a reversal of the erosion process, an increase in water retention capacity and nutrient availability for plants. The increase in the amount of soil organic matter (SOM) also leads to lower emissions of greenhouse gases (mainly CO2, CH4, N2O) into the atmosphere and a reduction in global warming.
Crop-livestock and forest integration systems (ILPF) are options for conservation agriculture, which enable the recovery of areas with degraded pastures, lead to improvements in the physical, chemical and biological conditions of the soil, increase the competitiveness of rural enterprises and diversify and stabilize income on rural property. Furthermore, crop rotation with legumes contributes to biological N fixation. Several research results indicate that there is a gradual increase in the cycling and efficiency of nutrient use by plants in ILPF.
Embrapa FertBrasil Caravan
The themes of planning and better use of land, good practices for the efficient use of nutrients, new fertilizers and inputs, sustainable management practices and new digital technologies, such as precision agriculture, are presented at the Embrapa FertBrasil Caravana (https://www.embrapa.br/caravana-embrapa-fertbrasil). At these events, lectures are held for technicians and producers, in the main producing regions of Brazil, providing information on technologies to make the use of fertilizers more rational.
Source: agrolink
