Advantages and limitations of fertigation

Compared with the conventional fertilization method, fertilization by the irrigation system has the following advantages 1 to improve the utilization rate of the fertilizer. Water and fertilizer are directly transported to the root soil, which can fully guarantee the effective supply of nutrients and the rapid absorption of roots. Because the water and fertilizer solution is evenly distributed in the soil, the nutrient distribution is highly uniform, and the absorption efficiency of the root system is improved. For micro-irrigation, the fertilization efficiency is greatly improved because the wetting range is limited to the area where the root is concentrated and the water and fertilizer solution is distributed to the maximum extent. Due to the small flow rate of the micro-irrigation, the time for the crop to absorb nutrients is correspondingly extended. Under drip irrigation, the water droplets containing nutrients slowly infiltrate into the soil, and the water in the root zone is saturated immediately after the soil is saturated, thus reducing the leakage of nutrients into the deep soil, especially the leaching of nitrate nitrogen. Traditionally, fertilization and irrigation are carried out separately. After the fertilizer is applied to the soil, the fertilizer is present in the soil due to lack of timely irrigation or insufficient irrigation, and the root system is not fully absorbed. The soil can reach water saturation during irrigation, but the irrigation time is short, so the roots absorb nutrients for a short time. Tomato cultivation under field drip fertigation system, nitrogen utilization rate can reach 90%, phosphorus reaches 70%, and potassium reaches 95%. The increase in fertilizer utilization means a reduction in the amount of fertilizer applied, which saves fertilizer.
2 Saving fertility labor, especially for vegetables and crops planted in greenhouses. In fruit tree cultivation, water and fertilizer management consumes a lot of labor. For example, in the production of bananas in South China, the number of annual fertilizations in some producing areas is as high as -5. Every time you apply fertilizer, you should dig a hole or open a shallow ditch. After fertilization, you should fill it with water. Simultaneous management of water and fertilizer after fertigation with facilities can save a lot of labor. The author found in the Shenzhen Xili Fruit Field that the use of drip irrigation can save more than 95% of labor. Now that labor prices are getting higher and higher, the application of fertigation technology can significantly save production costs.
3 Flexible, convenient and accurate control of the amount and time of fertilization. According to the crop nutrition rules, targeted fertilization, to do what is missing, to achieve precise fertilization. For example, in the shoot period, the fruit tree mainly needs nitrogen; in the young fruit stage, various nutrients such as nitrogen, phosphorus and potassium are needed; in the late stage of fruit development, the demand for potassium increases. According to the nutritional characteristics of crops, formulas can be formulated for each period to provide complete nutrition for crops. Depending on the flow and time of irrigation, the amount of fertilizer used per tree or unit area can be accurately calculated.
4 Fertilization in a timely manner, nutrient absorption is fast. For intensively managed farms or orchards, the fertilization task can be completed in a short time, and the crop growth rate is uniform, which is conducive to rational arrangement of field operations. The author's investigation on the time of fertilization of lychee drip irrigation in Shenzhen Xili fruit field showed that 52ha lychee can be completed by fertilization for one person for 24 hours, but in the past manual operation, it took 32 people to complete it in one week.
5 is conducive to the application of trace elements. Metal trace elements are usually applied in a chelated state, which is more expensive, and the micro-irrigation system can achieve accurate supply, improve fertilizer utilization rate, and reduce application cost.
6 improve the soil environment. The uniformity of micro-irrigation irrigation can reach more than 90%, which overcomes the soil compaction that may be caused by dredging. Micro-irrigation can maintain good water and gas conditions without substantially destroying the original soil structure. Due to the small amount of soil evaporation, the long-term maintenance of soil moisture, soil microbial growth is strong, which is conducive to soil nutrient conversion.
7 The micro-irrigation method can make the crop grow normally under marginal soil conditions. For example, sand or sand dunes have poor water holding capacity, and there is almost no lateral diffusion of water. Traditional watering is easy to leak deep, and it is usually difficult for crops to grow normally. Micro-fertilization technology ensures that crops grow normally under these conditions. Foreign countries have used the advanced drip irrigation and fertilization technology to develop deserts and carry out successful cultivation of commercial crops. Israel has widely used micro-irrigation and fertilization technology to produce sweet peppers, tomatoes, flowers, etc. in the southern desert, becoming the famous “vegetable basket” base in Europe in winter.
8 Application of micro-irrigation can increase the ability of crops to withstand risks. In recent years, droughts in many areas of southern China have lasted for a long time, and the plots with micro-irrigation and fertilization have high yield and stable yield, while the artificial irrigation plots have low seedling rate and low yield. Due to the good growth of crops fertilized by micro-irrigation, the crop's ability to resist stress is relatively improved.
9 The use of fertigation techniques is conducive to environmental protection. China's current fertilization per unit area is among the highest in the world, and the utilization rate of fertilizer is low. Due to unreasonable fertilization, great waste of fertilizer is caused. The loss of large amounts of fertilizer has caused groundwater pollution in some areas and eutrophication of rivers and lakes. By controlling the depth of irrigation, it is possible to avoid the leaching of chemical fertilizers into deep soils, especially the leaching loss of nitrate nitrogen can be greatly reduced, thereby avoiding or reducing soil and groundwater pollution.
10 Water and fertilizer interaction in fertigation, giving full play to the maximum benefit of water and fertilizer, significantly reducing the amount of water used.
The adoption of fertigation fertilization technology is conducive to standardization cultivation, and fertigation fertilization technology is an important technical measure in modern agriculture. Irrigation and fertilization has been promoted as a standard technical measure in crop cultivation manuals in some areas.
Limitations of fertigation and fertilization 1 One-time investment is large. According to the market price of irrigation equipment and fertilization equipment in recent years, Daejeon uses irrigation and fertilization, generally investing between 300 and 1,000 yuan per mu of equipment, while investment in greenhouse fertigation is higher than that of large days.
2 Irrigation and fertilization has certain requirements for management, and poor management can easily lead to clogging of the dripper.
3 Fertilizers used for irrigation have higher requirements for solubility.
4 In arid and semi-arid areas, due to fertigation usually only wet part of the soil, root growth may be confined to the wet zone of the emitter, which may limit root growth and make the plant short.
5 Long-term application of micro-irrigation and fertilization, especially drip fertigation, is likely to cause salt accumulation at the edge of the wet zone. This problem does not exist in southern China.
6 Special circumstances such as accidents, power outages, etc., sometimes reflux occurs in the system, polluting the irrigation water source.