On this World Water Day, March 22nd, the Agronomic Institute (IAC-APTA) will hold the "1st Meeting on Water in Agriculture". The objective is to disseminate information that can contribute to demystifying the idea that agricultural activity is a villain in the use of water resources. Although it is a large user of water, scientific data shows that 90% of the water used in irrigation returns to the environment through plant transpiration. Another mistaken idea that needs to be corrected is the farmer's belief: he believes that the more water he uses in irrigation, the better his crops will perform. And it's not like that. To achieve efficiency and sustainability in irrigation, it is necessary to adopt adequate water monitoring, management and management. Excess, in addition to not being beneficial to the plant, can also cause soil erosion and compaction. The free event will start at 8:30 am, at the IAC Headquarters, in Campinas.
“The process of growth and development of plants with high production and productivity involves a large volume of water, but the plant sweats around 90% of this consumed volume, which returns to the atmosphere in the form of vapor”, explains Regina Célia de Matos Pires, researcher and deputy director of the IAC, of the Department of Agriculture and Supply of the State of São Paulo.
The scientist emphasizes that water is an input in irrigated agriculture, just as nutrients are in other cultural practices. Plants need water input from rain or irrigation. What must be done is the appropriate use of the water resource involved in this process, via irrigation methods that promote efficiency and are properly adjusted.
For the event organizers and IAC researchers, Jane Maria Carvalho Silveira and Afonso Peche Filho, planning and adequate use of water is fundamental for the environmental, economic and social development of Brazilian agriculture.
The dynamics of water in soil, plants and atmosphere need to be understood and require monitoring. The climate is the most variable of these factors and, therefore, monitoring its data provides a basis for actions in crops. For example: faced with the fact that there will be no rain, the farmer knows that he needs to irrigate. If the data shows a high level of plant transpiration, it is a sign of the need to replace the water. The problem is that this equipment has complexity and costs that restrict its use in production areas.
To collaborate, the IAC has been presenting the water demands of different crops, with indicators of water use efficiency. Studies in this area began before the 1950s in different cultures. Since then, there has been several research involving the different phases of the plant and how they affect water consumption, the main critical periods of water deficit in different species and, more recently, the adoption of aerial images to assist in this understanding.
“We have management techniques that show crop response with application of 80% of the water, that is, with a saving of 20% of water and high productivity, showing which materials respond best to deficit irrigation”, says Jane.
Another possibility lies in cultivars developed by the IAC with greater tolerance to water stress, as occurs with some beans and sugar cane, for example.
This knowledge, associated with information such as the slope of the land and the hydrography of the region, serves as a basis for efficient management of water resources, in order to maintain sustainability and the expected productivity of each crop.
“The sustainability of agriculture depends on efficient irrigation, which makes food security viable. We can achieve water security by adopting proven efficient management in our scientific studies,” she states.
The IAC recommendation is to adopt water management strategies that include water deficit irrigation, that is, offering the plant a quantity of water lower than the total demand. Another orientation is the control of blades with monitoring via soil or plant sensors, or even with a meteorological station associated with soil conservation techniques such as contour lines and direct planting. These strategies provide the farmer with information that guides him on how much water to use for irrigation in an efficient and sustainable way.
According to Regina Pires, excess water does not favor the good development of the crop. When the soil is flooded, its porous spaces are filled with water and therefore there is no oxygenation. And plants need oxygen in the soil for good water absorption through the root system. “Without oxygen in the soil, the plant does not absorb water, even when water is available”, highlights the deputy director of the IAC.
“When the amount of water applied in irrigation increases without criteria, the use for the benefit of crop productivity continues to a certain extent. But the gains are directly linked to monitoring water in the plant and soil, water management and its management”, comments Jane.
The management of water use in agricultural activities will be addressed by IAC researcher, Afonso Peche Filho. For him, in an agricultural area, water presents itself in different aspects according to the occupation and use of the land. “The property is part of the dynamics of the hydrological cycle and its areas show ecohydrological characteristics over time. This “hydrological complex” manifests itself with different behaviors depending on the time of year,” he comments.
According to the researcher, the spatial organization of properties considers the so-called “occupation scenario”, which are productive, protected, built, neighboring, humid areas and transportation areas. There are also “seasonal scenarios”, referring to spring, summer, autumn and winter, and “use scenarios”, which involve water types, availability, demand and water scarcity.
The objective of the diagnosis is to identify management elements. Elements related to the administration, management and operation of any type of water.
“The diagnosis will raise a set of activities in which the occurrence and characterization of different hydrological situations need to be considered. “The intimate relationship between water and the occupied space and the product of these relationships determine the management model to be adopted on the property”, he states.
Aimed at professionals in the field of agricultural and environmental sciences, agricultural administrators, teachers, students and farmers, the event is supported by Fundag and the Brazilian Irrigation and Drainage Association.
The event will feature a lecture on Sustainability and Irrigated Agriculture in Brazil, with professor from the Federal University of Viçosa, Everardo Chartuni Mantovani. The IAC researcher, Angelica Prela Pantano, will talk about Agroclimate in São Paulo, the topic of Water Management on Agricultural Property will be addressed by the researcher, Afonso Peche Filho, and IAC research aimed at efficiency in the use of water in irrigation systems will be the theme of the lecture by the researcher, Jane Maria Carvalho Silveira.
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