Unreasonable fertilization is usually caused by the unreasonable amount of fertilization, fertilization period, and fertilization methods. Common ones are:
1, fertilization shallow or surface application. Fertilizers are volatile, lost or difficult to reach the roots of crops, which is not conducive to crop absorption, resulting in low fertilizer utilization. Fertilizer should be applied to the seed or plant 16-26 cm below the side.
2, double chlorine fertilizer. The compound fertilizer produced by ammonium chloride and potassium chloride is called double-chlorine fertilizer, and contains about 30% chlorine. It is easy to burn seedlings and should be watered in time. Chlorine-free fertilizers cannot be applied to saline-alkali and chlorine-sensitive crops. Excessive application of potassium chloride to leaves (stem) vegetables not only causes the vegetables to be less tender and more fibrous, but also makes the vegetables taste bitter, with poor mouthfeel and low benefits. The urea-based compound fertilizer has high nitrogen content, and the biuret has a slightly high nitrogen content. It is easy to burn the seedlings, and attention should be paid to watering and fertilization depth.
3. Improper application of chemical fertilizers. Due to improper application methods, it may cause fat damage, burning seedlings, plant wilting and so on. For example, excessive application of chemical fertilizers or insufficient soil moisture after fertilization may cause the soil solution concentration to be too high, and the roots of the crops may be difficult to absorb water, causing the plants to wilting or even die. Excessive application of nitrogen fertilizer, a large amount of ammonia or ammonium ions in the soil, on the one hand ammonia volatilization, the formation of alkaline small water droplets in the air droplets, burning crops, causing scorch spots on the leaves; on the other hand, ammonium ions in the drought The soil is easily nitrified and converted into ammonium nitrite under the action of nitrosating bacteria. The gasification produces nitrogen dioxide gas, which will poison the crops, and irregular water-like plaques appear on the leaves of the crops, and the veins gradually turn white.
In addition, when there is too much ammonium in the soil, the plant will absorb too much ammonia and cause ammonia poisoning.
4. Excessive use of certain nutrients. In this way, not only will the crop be poisoned, but it will also hinder the absorption of nutrients by the crop and cause deficiency. For example, excessive nitrogen application can cause calcium deficiency; excessive nitrate nitrogen can cause chlorosis in the absence of molybdenum; excessive potassium can reduce the effectiveness of calcium, magnesium, and boron; excessive phosphorus can reduce the effectiveness of calcium, zinc, and boron.
5, fresh manure should not be directly applied to vegetables. Fresh human excrement contains a large number of germs, toxins and parasite eggs. If it is applied directly without decomposing, it will contaminate vegetables and easily spread diseases. It can be applied after high-temperature fermentation or harmless treatment. In the process of decay, the unfertilized livestock and poultry manure will produce a large amount of harmful gases such as hydrogen sulfide, which will easily cause the vegetable seeds to suffer from hypoxia and suffocation; and generate a large amount of heat, which may cause vegetable seeds to burn or root rot, which is not conducive to vegetable seeds. Germination grows.
In order to prevent the occurrence of fertilizer damage, attention should be paid to rational fertilization in production. First, increase the application of organic fertilizer to improve soil buffer capacity; second, apply fertilizer according to regulations. According to the soil nutrient level and the demand for nutrients in the crop, rational fertilization, do not arbitrarily increase the amount of fertilization, apply the topdressing to master the principle of light fertilizer and diligence; the third is full-layer fertilization. The same amount of chemical fertilizer, when applied locally, often causes the concentration of local soil solution to rise sharply, damage the root system of the crop, and change to full-layer fertilization, so that the fertilizer is evenly distributed throughout the plough layer, so that the crop can avoid damage.
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Oil Drilling Rig
With the continuous development of drilling production, the use conditions of drilling rigs have become more and more diversified, and various types of drilling rigs have appeared accordingly. Factors affecting the type and composition of drilling rigs include drilling method, drilling depth, borehole size and drilling tool size, and drilling area conditions (such as electricity or fuel, transportation, and meteorological conditions).
1. According to drilling method
(1) Impact drilling rigs, such as wire rope impact drilling rigs (drilling rigs), vibration drilling rigs, etc.
(2) Rotary drilling rigs, such as those used in rotary drilling.
(3) Downhole power drilling tools, such as rotary drilling tools, turbo drilling tools, screw drilling tools, electric drilling tools, etc.
2. Divided by drilling depth
(1) Ultra-deep well drilling rig. It adopts a drilling rig with a diameter of 114 mm drill pipe, a nominal drilling depth range of more than 7000 meters, and a maximum hook load of more than 4,500 kN.
(2) Deep well drilling rig. The drill rod is 114 mm in diameter, the nominal drilling depth is 4000-7000 meters or more, and the maximum hook load is 2250-4500 kN or more.
(3) Drilling rigs for medium and deep wells. It adopts a drilling rig with a diameter of 114 mm drill pipe, a nominal drilling depth range of 1500-4000 meters or more, and a maximum hook load of 900-2250 kN or more.
Three, according to power equipment
(1) Diesel Engine-driven drilling rigs, which use diesel engines as power through mechanical transmission or hydraulic transmission.
(2) AC driven drilling rig, suitable for use in oil fields with industrial power grids.
(3) The drilling rig is driven by direct current, and the working unit is driven by a direct current motor.
Fourth, according to the driving mode
(1) Drive alone. Each working machine is driven by generators of different sizes, which are mostly used for electric drive. The transmission is simple and easy to install, but the power utilization rate is low and the total equipment mass is large.
(2) Unified drive. The three working units of drawworks, drilling Pump and turntable are driven by the same power unit. Most drilling rigs use this scheme. The unified drive can also include only one drilling pump, and the other drilling pump is driven separately. The unified drive drilling rig has high power utilization and can be adjusted mutually when the engine fails, but the transmission is complicated, installation and adjustment are troublesome, and the transmission efficiency is low.
(3) Group drive. The combination of power is between individual drive and unified drive. There are two options for three working machines. The power utilization rate of this kind of drilling rig is higher than that of a single drive, and the transmission ratio is simple to drive in a unified manner. Two sets of working machines can also be installed on different heights and scattered sites.
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