Accurate collection and treatment of soil samples

The steps of soil analysis generally include the collection of soil samples, analysis of soil samples, formulation formulas for soil testing and formulating fertilization, and the use of fertilization advice cards to guide crop fertilization. Therefore, soil sample collection and treatment technology is a basic and key technology for soil testing and formula fertilization. Soil samples are representative and their analytical results are practical. If the collected soil sample is not representative, the analysis of the soil sample is accurate, and the analysis results are not practical. Using the analysis formula made from the data to guide the production is wrong. Now we will introduce soil sample collection and fertilization soil sample collection and treatment technologies and discuss with our peers.

1 Preparation before sampling

1.1 Division of sampling units

Soil testing and formula fertilization cannot and does not necessarily require sampling and analysis of each plot. Analysis of soil samples is mainly to understand the nutrient supply capacity of the soil. The nutrient supply capacity of soil is related to the parent material of soil, soil type, topography, crop planting conditions, long-term fertilization habits and other factors. Before the soil samples were collected, the soil was divided into several areas with relatively uniform soil fertility according to the above-mentioned differences in the soil. This is called a sampling unit.

Different soil types must be divided into different sampling units. You can use the soil maps at all levels of counties, townships, and villages to divide the sampling units and set sampling plans, including sampling locations, sampling lines, and sampling quantities. If a village (slope) has the same soil parent material, soil type, topography, crop conditions, and long-term fertilization habits, it can be divided into paddy fields, cane fields, dry lands, and orchards according to planting conditions. Divided into 1, 2, 3 small units. The area represented by each unit is 617~1313hm2 in the plain area and 313~617hm2 in the hilly area.

1.2 Preparation of sampling tools

The necessary tools for sampling are ring cutters, aluminum boxes, sampling boxes or plastic bags, ropes, pencils, and sampling labels. Conditional GPS (Global Positioning Satellite) can be used to determine the latitude and longitude of the sampling field.

2 Collect soil samples

2.1 sampling time, field block and sampling depth

Soil analysis for soil testing and formula fertilization is mainly to analyze some data related to soil nutrient supply. The soils collected at different times are different from those related to soil nutrient supply. Soil testing and formulating Fertilization The sampling time of soil samples can be obtained after crops are harvested or before sowing and fertilization, and is generally suitable for sampling from autumn to winter and early spring. After the fruit is harvested, the orchard is collected before the first fertilization. Within a sampling unit, select one block of a typical field in the center position as a sampling field with an area not less than 667m2. Sampling plots can not be selected on roadsides, sewage ditches, manure ponds, and other special plots. Sampling depth: The roots of crops such as grains, oils, sugars, and vegetables are mainly distributed in the tillage layer. Tillage layer soil should be taken as the sample. The sampling depth is generally 15~2cm; the root distribution of fruits and other crops is deeper, and the sampling depth is generally 2 ~4cm.

2.2 sampling points and distribution

The results of a soil sample test represent the soil condition of a sample cell area. If the samples taken are not representative, there is no practical value even if the tests are accurate. Therefore, it is necessary to sample multiple points in the sampling field and mix well. The number of sampling points depends on topography, fertility balance, and the size of the sampling field. The number of points with complex topography and geomorphology is more; the fields with large differences in fertility are correspondingly larger than those with even fertility; the area of ​​large plots is smaller than that of plots. The average field size is less than 17hm2, taking 5~1 points; 17~313hm2, taking 1~15 points; more than 313hm2 taking 15 points or more. The principle of distribution of sampling points is uniform distribution and cannot be too concentrated. Attention should be paid to avoiding special locations such as fields, trenches, fertilizer piles, and front crop fertilization. According to the field size, topography, terrain, fertility and other factors, using diagonal, checkerboard and serpentine sampling methods. The area of ​​plots is small, diagonal sampling method can be used; the area of ​​plots is medium, and checkerboard sampling method can be used; the area of ​​plots is larger, and serpentine sampling method can be used.

2.3 Sampling

At each point of sampling, surface impurities (if there are obvious impurities) are shoveled first, then a V-shaped earth pit is shoveled with a ring knife, the depth is the same as that of the plough layer, generally 15 to 2 cm, the earth pit is shoveled into a vertical surface, and then Vertically scoop a piece of soil that is 2 to 5 cm thick and has the same thickness from top to bottom. Use the knife to vertically cut the left and right sides of the soil block. Leave the long soil block as the sampling soil block. The sampling depth of each sampling point should be uniform, and the thickness of the upper and lower layers of the taken soil should be the same. The weight of the sampling soil should be approximately equal. Trace elements are generally not tested now. If trace elements are to be tested, they should be sampled with non-metallic instruments.

2.4 Sample weights, labels, and bagging

Samples sent to the laboratory require a weight of about 1 kg. In the sampling process, the soil collected at multiple points is called a mixed sample. The weight of the mixed sample is large, so some samples should be removed. The method is to mix the samples on a plastic sheet to remove impurities such as animal and plant residues and gravel.

If there are too many impurities such as animal and plant residues and gravel, the mixed samples and impurities should be separately weighed and recorded. Need to smash large pieces of sample, pay attention to mixing, spread into a circle, the middle of the cross divided into four copies, then remove two copies of the diagonal, to take two copies, this method is called quarter method. If there are many samples, mix the samples again and repeat the quartering until the final weight of the sample is about 1kg. Use pencils to write sample labels. Each sample must contain 2 labels. The label includes the serial number, sampling location, sampling depth, field location (or latitude and longitude), farmer name, sampling person, and sampling time. Samples can be packed in special sampling boxes or plastic bags. Samples are packed in a uniform sample bag with a label inside and outside.

2.5 Sample Production Status Survey

It is an indispensable task to carry out a survey of production status when sampling. Its role is to provide reference for making correct fertilization decisions. After the samples are submitted to the laboratory for testing, if no survey data is provided on the status of production, it will not be possible to make a fertilization decision, that is, no formula can be formulated. Providing unrealistic production status data and making fertilization decisions are also wrong. The survey of production status includes: locations, including counties (districts), townships, villages, villages, and ridges; names of farmers; soils, subcategories, soils, and soil types; previous year's crop varieties, annual production, and crop varieties of the current year Perennial fertilization types and quantities, including organic fertilizers, nitrogen fertilizers, phosphate fertilizers, potash fertilizers, compound fertilizers, etc., the amount of fertilization should be recorded according to the actual amount of fertilization.

3 sample processing

After the samples are collected, they cannot be promptly sent to the laboratory for testing. They should be spread on plastic sheets in a timely manner. Ventilation, drying and avoiding the presence of rice have a certain inhibitory effect on the growth and development of shoots. When the growth of the panicles is poor, this inhibition is even more pronounced. The growth dominance of Zhengda 619 is strong. In the case where the vegetative growth period has passed, the organs develop faster, the leaves become faster, the collateral growth rate increases, and more spikes are formed. Only two or three or more ear and axillary buds can be issued by the axillary buds, ie bifurcated and multilobe.

In addition, the nutrition in the plant cannot be transmitted normally through the ear of the finger, but through the sprouting of axillary buds, ie, the second, third or even more growing ears, especially in the case of nitrogen fertilizer and potassium fertilizer, due to the development of The third and fourth stages are delayed in transition to the fifth stage. Therefore, several axillary buds can grow at the same time. The second or third axillary bud in the upper part of the plant grows and exceeds the top axillary bud in growth. In the six stages and subsequent stages until maturity, a few ear buds almost simultaneously developed fruit spikes. This re-grown corn borer has not obtained pollen and is not stunted, and it is impossible to form a hollow shell as a spike. The filaments and heads are not stunted and cannot be pollinated into normal ears. For example, a household of Huang Shaoxing in Tongtong Village of Tanglun Village, Chia Da 619 has an area of ​​66617m2, Mu Shiji has 25 pounds of manure, 1 kg of highly concentrated compound fertilizer, and 12 kilograms of chicken manure. The rest of the fertilizer has the same amount as conventional ones. More than %, all fields lost.

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