Soil moisture has an extremely important influence on food production. In experiments on soil moisture monitoring of grain arable land, selection of plots is the main site for investigating soil moisture content and requires good representation in terms of cultivated land conditions and soil types. Determining field water holding capacity Field water holding capacity is an important parameter to measure soil moisture content. It is the soil water content when the groundwater table is low, the maximum amount of suspended water in the capillary tube is not connected with groundwater, and it is the upper limit of available soil water available for crops. . By measuring field water holding capacity, it is of practical significance to understand the local soil moisture conditions and formulate scientific farming measures. The field water holding capacity was measured according to the national terrestrial quadrat technical standards and measured by the district irrigation method. Measuring tools, instruments and supplies: test methods: Printing Mesh Stretching Machine Machine for T Shirt Silk Screen,Polyester Mesh Making Equipment,Nylon Bolting Cloth Stretcher Xiahua Envirotech Co., Ltd. , http://www.jsfiltercloth.com
Shantou, shovel, water transport tools such as vehicles, buckets, water scoops, plastic film, grass (for the establishment and finishing of test sites); drilling soil drilling (sample drilling); test equipment, soil moisture sensors and rapid soil moisture test Instrument, soil moisture tester; record clips and pens (hand-held test parameters); computer (processing data).
First, we need to measure the flat land with an area of ​​4m2 (2m × 2m) on the section to be measured, remove the weeds, remove the plant rhizomes, put a little levelling on it, and build a relatively strong earthworm around the base as a test site.
Next, at the edge of the prepared test site 1.0 to 1.5m, according to the depth of sampling required to measure the amount of water in the field, the soil moisture tester was used in four levels of 0 to 10, 10 to 20, 20 to 40, and 40 to 60 cm. Take two duplicate soil moisture content data to determine the amount of natural soil irrigation. According to actual calculations, the average soil moisture content of the plots was 34.04%, 36.67%, 39.46%, and 40.73%, respectively (using volumetric water content in m3/m3).
Finally, the amount of irrigation in the plot is calculated using Q=2×(θ1-θ2)×S×H/100. There may be two kinds of results: if it is positive, it means that the natural soil water content is less than the theoretical field water capacity, which requires manual irrigation; if it is negative, it means that the natural soil water content is greater than the theoretical field capacity, and the soil moisture does not need to be saturated. Irrigation. In the formula, Q is the amount of irrigation in the plot (m3); θ1 is the theoretical value given by the monitoring plan. It is the average field capacity of each soil depth, which is expressed by the volumetric moisture content. Generally, 30% of the sand is taken and the loam is taken. 37.5%, clay takes 40.5%, the value of loam is 37.5%; θ2 is the average value of measured moisture content of each layer of natural soil before irrigation, substituting the weighted average formula θ2=(θ0～10+θ10～20+2) ×θ20~40+2×θ40~60)/6. The calculation result is 38.51%; S is the area of ​​the irrigation site, the case is 2m×2m=4m2, and H is the soil depth to be measured. The case is 0.6m. . Substituting into the formula, the amount of irrigation Q in the plot is -4.85m3, showing a negative value. The reason is that heavy rain fell 2 days before the survey, indicating that the soil water content has reached saturation, the soil is too wet, natural precipitation replaces artificial irrigation, and the community no longer needs labor. Irrigation should be covered with a film cover in time, and the amount of water in the field should be measured after the completion of gravity infiltration.
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