Greenhouse Water Treatment Systems
Greenhouse Water Treatment Systems
SOILLESS AGRICULTURE (HYDROPONICS)
Every living organism requires essential minerals to grow. The type and amount of these minerals vary from one organism to another. In addition, the environmental conditions also affect growth. This rule applies to plants as well. Therefore, to control adverse environmental conditions and achieve year-round production, people have developed greenhouse methods. In field agriculture, we can provide a plant with its needs through soil or irrigation, but we cannot control its surrounding environment.
SOIL-BASED AGRICULTURE
Soil-based agriculture is the cultivation of plants in contact with soil under suitable conditions. Greenhouses are structures covered with light-transmitting materials such as glass, plastic, or fiberglass that allow environmental conditions to be controlled or adjusted for optimal plant growth.
In regions with a mild climate, vegetable and fruit cultivation is typically carried out under glass covers for vegetables and plastic covers for fruits. Professional greenhouses are fully galvanized, assembled with screws, and are designed based on static calculations, the geographical location, and the tonnage of the products grown inside.
Artificial Conditions Provided in Greenhouses:
GREENHOUSE CLIMATE CONTROL CONDITIONS
Heating
Although covering plants can help maintain the desired temperature, it might not always be sufficient. In such cases, heating systems are installed inside the greenhouse to keep the temperature within the desired range.
Ventilation
The humidity inside the greenhouse is maintained through ventilation systems, which also facilitate plant pollination.
Irrigation and Fertilization
This involves scheduling irrigation and determining the appropriate methods to water the plants, as well as applying fertilizers when needed for healthy growth.
Pesticide Application
Pesticide systems are installed in greenhouses to effectively combat microbes that harm plants. When pesticides are applied to the soil, irrigation systems are used if appropriate. If the pesticides are to be applied to the above-ground parts of the plants, a separate system is used.
Greenhouse Misting Systems
A misting system is used to rapidly cool the environment and provide the necessary humidity for the plants. It is one of the systems installed in greenhouses to supply the required moisture and to lower the ambient temperature. The misting technique bridges the gap between air humidification and soil irrigation.
Misting System Operating Principles
Tiny water droplets evaporate, causing cooling. The surrounding heat is absorbed. Water droplets finer than 10 microns are dispersed by the spray nozzles, increasing humidity without wetting the plants or the environment.
Applications of the Misting System
Water Requirements for Misting Systems
When designing greenhouse irrigation systems, it is important to choose systems that save water and energy. Water savings should minimize the amount of water that runs off the surface, infiltrates deeply, or evaporates, while energy savings should be achieved by reducing the evaporation of irrigation water and the latent heat lost from the covering. Modern greenhouses often use drip irrigation systems with spaghetti drip emitters that water individual plants, while moderately technological greenhouses may use drip systems that water furrows directly planted in the soil.
The water used for irrigation must be analyzed, and based on the results, the source should be deemed suitable for irrigation.
Water Classification Based on Plant Tolerance to Boron:
Boron Concentration in Irrigation Water (mg/l)
| Irrigation Water Class | Sensitive Plants (mg/l) | Moderately Tolerant Plants (mg/l) | Tolerant Plants (mg/l) |
|---|---|---|---|
| I | Less than 0.33 | Less than 0.67 | Less than 1.0 |
| II | 0.33 – 0.67 | 0.67 – 1.33 | 1.0 – 2.0 |
| III | 0.67 – 1.0 | 1.33 – 2.0 | 2.0 – 3.0 |
| IV | 1.0 – 1.25 | 2.0 – 2.5 | 3.0 – 3.75 |
| V | More than 1.25 | More than 2.5 | More than 3.75 |
Maximum Allowable Concentrations of Heavy Metals and Toxic Elements in Irrigation Water
| Elements | Maximum Total Amount Allowed per Unit Area (kg/ha) | Limit Values for Continuous Irrigation on All Types of Soil (mg/l) | For clay soils (pH 6.0 – 8.5) irrigated for less than 24 years (mg/l) |
|---|---|---|---|
| Aluminum (Al) | 4600 | 5.0 | 20.0 |
| Arsenic (As) | 90 | 0.1 | 2.0 |
| Beryllium (Be) | 90 | 0.1 | 0.5 |
| Boron (B) | 680 | - | 2.0 |
| Cadmium (Cd) | 9 | 0.01 | 0.05 |
| Chromium (Cr) | 90 | 0.1 | 1.0 |
| Cobalt (Co) | 45 | 0.05 | 5.0 |
| Copper (Cu) | 190 | 0.2 | 5.0 |
| Fluoride (F) | 920 | 1.0 | 15.0 |
| Iron (Fe) | 4600 | 5.0 | 20.0 |
| Lead (Pb) | 4600 | 5.0 | 10.0 |
| Lithium (Li) | - | 2.5 | 2.5 |
| Manganese (Mn) | 920 | 0.2 | 2.0 |
| Molybdenum (Mo) | 9 | 0.01 | 0.05 |
| Nickel (Ni) | 920 | 0.2 | 2.0 |
| Selenium (Se) | 16 | 0.02 | 0.02 |
| Vanadium (V) | - | 0.1 | 1.0 |
| Zinc (Zn) | 1840 | 2.0 | 10.0 |
Based on the parameters specified in the tables above, the quality of the water used for irrigation must be ensured through appropriate water treatment systems.
