Water is the source of life. It is an essential factor of production, both plant and animal. Currently, almost 30% of available fresh water in Europe is used by agriculture. The demand for water continues to grow in contrast to the size of resources that are constantly shrinking. This is, inter alia, the effect of intensive farming and adverse climate changes that result in more and more frequent anomalies. Therefore, one of the most important challenges that the agriculture is facing today is implementing appropriate farming practices and solutions in the field of efficient water management. This requires knowledge and awareness how to influence the hydrological cycle beneficially.
There are many tools for efficient water use. The most commonly used by farmers are:
- using crop rotation
- accumulation of rain water
- actions to retain water in the soil
- re-use of the same water
- adjusting the time of sowing to the temperature and amount of rainfall
- cultivation of varieties more resistant to certain weather conditions
- efficient irrigation of fields
From the point of view of water savings, activity of the administrative bodies is also significant, as they force farms to apply for permissions to use water. The price per unit of water and setting a maximum level for water use are the two most important stimulators for more effective use of water sources.
Control of water content in the soil is necessary in the context of meeting the needs of grown plants. This activity is also meant to use water resources in a more effective way and to promote savings. Soil moisture measurement in this aspect is essential. Based on this it is not only water content in the soil that is assessed but also its potential. Understanding both of these values makes it possible to accurately determine the level of demand and availability of water for plants in a given moment.
HOW TO PERFORM THE MEASUREMENT?
There are a number of methods. The most popular are:
- tensiometric measurement
- electrical resistance measurement
- electric permittivity measurement
- neutron scattering measurement
- gravimetric measurement.
Each of the above methods has its advantages and disadvantages, and the choice of how to measure the soil moisture depends mainly on the possibilities and expectations of a farmer. However, regardless of the preferences for these methods, it is necessary to take into accounts a set of rules that affect the accuracy and efficiency of measurements made.
The most important are:
- placing the sensors in locations where the roots actually intake the water actively
- placing on the field more sensors at different depths (important in the context of various soil quality and the terrain)
- observing weather conditions in order to take account of the rate of water evaporation from the soil.
THE PRACTICE OF OUR COMPANY
On our farm these measurements are carried out with use of modern, wireless sensors, equipped with GPRS modems for remote reading of data. Furthermore, we have a DSS (Decision Support System) software on our computers that uses information received from these sensors together with an individual weather forecast for our farm, this creating for us a detailed plan for irrigations. This lets us know precisely when, where and how much water should be used for irrigation. Not only does this system make it easier and more effective to make decisions, but it also improves the efficiency of our actions significantly.
A properly designed irrigation system improves the quantity and quality of the yield on the farm, and it can also be used for restoring the resources of surface water.
However, it might have also a number of negative consequences of it would not be used in a precise and planned way. We are talking about destruction of the soil structure, leaching of nutrients, contamination with water that is not pure enough, hazards of diseases transmitted in water or excessive exploitation of natural water resources.
With regard to the way the water is distributed, there are a few types of irrigation:
- furrow irrigation
- capillary irrigation
- drip irrigation
- usig center pivot
- flood irrigation
IRRIGATION SYSTEM AT OUR FARM
Our company uses pivots and reels with water guns for soil irrigation. They work exclusively on potato plantations as this crop is very sensitive to water scarcity.
Using pivots and reels / water guns, however, involves many difficulties. One of them is the size and terrain, where the fields are located. These two aspects substantially determine which device is best in certain conditions.
The most demanding devices in this respect are pivots which are only suitable for larger and flat fields due to their construction and way of operation. The shape of land irrigated by pivots is circular so it is necessary to place the center precisely. An obstacle for pivots would be any poles or power lines, as well as uneven terrain. The reels with water guns are less demanding, but their use required greater effort. In addition, the stream of rain produced by them is very sensitive to wind, which can weaken the efficiency of irrigation.
We developed the irrigation system which, supported by soil moisture measurement and with testing water quality, involves continuous monitoring and supervision of the devices working on our farm in such a way to constantly improve its performance. This approach translates not only to increased quantity and quality of the yield but also to effectiveness of management of available water resources
The latter require us to work constantly towards finding new solutions in the subject of crop irrigation. This is not only the enhancements of existing irrigation systems, such as the ability to control separate pivot nozzles via GPS or improving its construction in a way that allows bending the arm to bypass obstacles. This also means developing new methods that will become the common denominator for such important issues like effectiveness and economy of irrigation and protecting the environment.
Irrigation of crops on farms uses huge amounts of water every year. Therefore using these resources requires obtaining a water permit from the local authorities. This is an instrument that regulates the amount of water intake and the amount, condition and composition of discharged wastewater. The "Water Law" act precisely defines the cases where it is necessary to obtain such a permit, what is the range of it and what are the duties resulting from the environment protection laws; it also indicates the actions to the interests of the people and the economy. Currently, the minimal water intake which requires a water permit is 5 m³ per day.
AVAILABILITY OF WATER IN OUR FARM
Our farm uses water from 7 nearby wells (ground water) and from the Łupawa river, which is a protected area, as placed on the list of Nature 2000. This fact substantially restricts our access to water, making us dependant on the natural environment. Water intake from the river is allowed from mid May to mid September, taking into account the level of water at a given moment. All actions that we take must conform with norms which serve to protect this precious natural habitat.
If the case of use of groundwater resources we are obliged to check and keep records of our daily use, while its cost is set based on a price of 1 m³. However, regardless of the source of water that we use, we check the quality of water that we use, especially in the aspect of possible chemical and microbiological contamination, thus protecting the crops from unwanted impurities.