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Application Of Soil Sensor
- Jan 16, 2018 -

Real-time monitoring of soil moisture (soil moisture)

1. definition of soil moisture

Soil moisture, or soil water content, is the physical amount of the dry and wet degree of the soil in a certain depth of soil. The humidity of the soil is restricted by the various components of the water balance of the farmland.

2. influence of soil moisture on crops

1) direct impact

The water is too high or too low to stop until the breathing, photosynthesis, growth and other life activities are stopped.

Soil moisture determines the water supply of crops, which directly affects the growth of crop roots. Only the soil moisture is suitable, the root water absorption and leaf transpiration can reach the equilibrium state.

The soil humidity is too low, the formation of soil drought, photosynthesis can not be normal, reduce the yield and quality of crops; serious water shortage caused crop wilting and death.

The soil humidity is too high, the soil aeration is deteriorated, the activity of soil microorganism is affected, and the life activities such as respiration and growth of the root of the crop are hindered. The root system was anoxic, asphyxia and final death.

The amount of soil moisture affects the temperature of the soil.

Example: the suitable soil water content of legume crops and potatoes is equal to 70% ~ 80% of the field water holding capacity and 60% ~ 70% of cereal crops. The soil moisture content is lower than the optimum value, reduced photosynthesis. The percentage of soil water content (field capacity) of all kinds of crops decreased at the beginning of photosynthesis: rice 57%, soybean 45%, barley 41%, peanut 32%.

2) indirect influence

The lodging and disease of A. plants

The soil humidity is too high, affecting the normal growth of crops on the part of the cause, breed, leggy lodging, all kinds of diseases.

B. depth of plant roots

In moist soil, the roots of crops are not developed, and their growth is slow, which is distributed in the shallow layer. The soil is dry, the root of the crop is ligation and extends to the deep layer.

Effect of C. on crop quality

Water has a great influence on the quality of crops. High temperature and less rain in summer, the content of protein in grain grain is high, and low temperature and rain are beneficial to the formation of starch in grain. After studying the chemical components of wheat in the world, a professional scholar pointed out that the wheat grains produced in the arid regions usually have high or very high protein content. The data showed that under irrigation conditions, the yield of wheat increased significantly and the starch content in grain increased, but the protein content decreased. In order to increase grain yield and not reduce its protein content, nitrogen fertilizer must be added under irrigation conditions.

D. affected field cultivation measures, sowing quality and harvest quality.

Such as the use of mechanical harvesting of potato in dry soil caking condition, will cause the potato and clods of the collision, the damage of potato.

Water demand for 1. crops

The water demand for crops is usually represented by the transpiration coefficient. The coefficient of transpiration refers to the amount of water consumed by a crop per gram of dry matter. The transpiration coefficient of the crop is not fixed.  The water requirement of different varieties of the same crop is different, and the same variety is planted under different conditions, and the water requirement is different. There are many factors affecting the crop water demand. The first is the weather conditions. The air is dry, the air temperature is high, the wind speed is big, the transpiration is strong, the crop is more water, and the water needs less. The second is the soil condition. Fertile soil or after fertilization, crop growth, dry matter accumulation, while the transpiration is not increased, so water demand less than in the barren land. Studies have shown that the lack of any element in the soil will increase the water demand. Especially when phosphorus and nitrogen deficiency are needed, the water demand is the most, and that of potassium, sulfur and magnesium is the second, and the influence of calcium deficiency is the least.

2. critical period of water requirement

In the whole life of a crop, the need for water is generally less than the need for water in the early and late stages of fertility.  The most sensitive period of water in the life of a crop is called the critical period of water. In the critical period, if the water is insufficient, it has the greatest influence on the growth and the final yield of the crops. For example, the critical period of water demand for wheat is from booting to heading. During this period, the plant metabolism is strong, the concentration of cell liquid is low, the water absorption capacity is small, and the drought resistance is weak. If the water is short of water, the differentiation of young panicles, pollination, fertilization and embryo development are all hindered, and the production is reduced in the end. In crop production practice, we should determine the irrigation period and irrigation quantity of crops, besides considering the critical period of water demand, we should also pay attention to the local precipitation and soil moisture.