Hydroponics is the main type of soilless culture. Hydroponics is the method of growing plants in a relatively closed environment which could store nutrient solution by the specific facility. This environment keeps relatively stable conditions needed for root growth such as water, fertilizer, gas and heat.
Nutritional value, taste and quality of hydroponic vegetables
The mineral nutrients that are essential for plant growth are all derived from soil or fertilized artificially. Mineral nutrient elements in hydroponic nutrient solution are regulated and supplied according to needing of different crops and different growth stages. Because during growth, nutrient supply is more timely than that of soil cultivation, the nutritional value and quality are higher of hydroponic vegetables.
There are many problems such as drought, waterlog, nutrient imbalance, insect bite, pathogenic microorganism infection with soil culture vegetables. Many secondary metabolites such as polyphenols, quinones, sesquiterpenes and other secondary metabolites should be secreted to resist these problems. Vegetables will accumulate more and more secondary metabolites. Most of these secondary metabolites are colored or bitter. On the contrary, all conditions of hydroponic vegetables are suitable or closer to ideal state. Vegetables will not accumulate excessive secondary metabolites. So the taste is also better than soil culture vegetables
Nitrite content of hydroponic vegetables
At present, people's concerns about the safety of hydroponic vegetables mainly come from whether the content of nitrite exceeds the standard.
les are suitable or closer to ideal state. Vegetables will not accumulate excessive secondary metabolites. So the taste is also better than soil culture vegetables.
The nutrient solution of hydroponics is circulating, and the dissolved oxygen content in the nutrient solution is always at a high level. That means the redox potential in the nutrient solution is higher, and there is no condition for reducing the nitrate to nitrite. Therefore, nitrite content of hydroponic vegetables is very low. With soil cultivation, the reduction condition is very easy to occur due to local soil (such as rain or irrigation). So vegetables grown in soil may also contain much nitrite. In addition, hydroponics is more controllable than soil cultivation. The nitrite content in vegetables can be controlled by regulating the quantity and timing of nitrate in the nutrient solution. But it is not possible with soil cultivation.
Utilization ratio of water and fertilizer
The average utilization rate of fertilizer with traditional soil cultivation is about 30%-50%. All the nutrients of hydroponics are water-soluble. Nutrients are supplied base on different varieties of crops and different growth periods. About 90%~95% or more fertilizer can be absorbed and utilized. Therefore, its nutrient utilization efficiency is very high, and the waste nutrient solution can be recycled after treatment, which will not cause pollution to the environment.
Because there is no problem of water leakage and runoff loss in soil cultivation, Utilization ratio of water is higher with hydroponics. The water consumption of hydroponic vegetables is only about 1/5~1/10 of soil cultivation. So hydroponics is suitable for promoting in area drought and water shortage.
In conclusion, the water and fertilizer supply for hydroponic vegetables is adequate and balanced, plus the environment of greenhouse is more suitable for vegetable growth. Therefore, compared with traditional soil culture, hydroponics has higher yield, better quality, better taste and higher safety.
Beijing Kingpeng International Agriculture Corporation
7th floor, Advanced Material Building, Feng Hui Zhong Lu, Haidian District,
Beijing, China, 100094
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