RU2137330C1 - Method for retention of soil water supply - Google Patents

Abstract

FIELD: agriculture, in particular, soil water retention method used in districts with cold winter and stable snow cover. SUBSTANCE: method involves providing stubble strips of different height during harvesting period; removing snow cover from soil in early spring. Width of strips free from snow is 3-4 m and of strips with snow cover 10-20 m. Removal of snow from strips is performed in direction transverse to remained stubble strip. Width of different-height stubble strip is selected within the range of 6-20 m. Method provides both soil moisture retention and soil desalinization. EFFECT: reduced cost of works and decreased moisture loss during early spring soil defrosting. 2 dwg, 2 ex

Description

 The invention relates to the field of agriculture and can be applied in areas with cold winters and stable snow cover, both for preserving soil moisture reserves and for desalination of solonchak soils.

 There is a method of preserving soil moisture reserves, including strip exposure of the soil from snow cover with a width of exposed stripes of 3-4 m and non-exposed stripes of 10 - 20 m (RF Patent N 2002388 A 01 B 13/16, A 01 B 79/00). The disadvantage of this method is the high cost of double exposure of the soil from the snow cover.

 The closest in its technical essence is a method involving the creation of stubble strips of different height during the harvesting period (Snow. Handbook. Hydrometeo Publishing House 1980, p. 92 - 93).

 The disadvantage of this method is that when thawing the soil, strips with a high stubble height thaw faster and the soil moisture pulled into them during the winter period under the influence of the pressure formed under the permafrost crust migrates back to the deep soil layers. In this case, only moisture remains blocked in bands with lesser stubble and deeper sections of soil freezing. It is impossible to solve this problem simply by increasing the width of some stripes and decreasing others because the sections of deep and shallow freezing of the soil have certain width limits to preserve soil moisture reserves, an increase in which leads to a decrease in soil moisture reserves.

 The objective of the present invention is to reduce the cost of carrying out and to reduce possible moisture losses during early spring thawing of the soil.

 The present problem is solved as follows. In a method of preserving soil moisture reserves, including the creation of uneven stubble strips during the harvesting period and early spring strip outcrop of soil from snow cover with a width of exposed strips of 3-4 m and non-stripped strips of 10 to 20 m wide, strip outcrop of soil from snow cover is transverse to the left stubble while the width of the strips of different stubble is selected at the rate of 6 - 20 m.

 The novelty of the proposed method consists in the application of two well-known technologies in a new combination, the combination of which has not been previously encountered, which allows to achieve higher results in the conservation of soil moisture than in each of them individually or together in violation of the indicated sequence and size of the strips.

In FIG. 1 is a diagram of the process of freezing soil
In FIG. 2 shows a diagram of the implementation of the proposed method.

 The diagrams show strips with high stubble 1 and low stubble 2, strips 3 exposed from snow 3, and strips with snow cover 4, areas of deep freezing 5 and areas of shallow freezing 6. After exposure of the soil from the snow cover, areas of rapid 7 are formed on it , average 8 and long 9 terms of thawing.

 The method is as follows. During harvesting, stubble strips of various cutting heights are left in the fields. In the frosty and snowy period, areas with low stubble freeze faster and deeper, as a result of which they accumulate a large amount of moisture coming to them from the deep layers of the soil. By spring, in areas with high and low stubble, snow cover of approximately the same thickness is formed, however, the density of snow cover, and therefore the moisture content in areas with small stubble, is twice as high as in areas with high stubble. At the beginning of snow melting, a strip outcrop of the soil from the snow cover is carried out across the striated stubble strips. As a result of exposure of the soil, it forms fast-thawing sections 7 located under high stubble and less frozen, sections of medium thawing period 8, located under low stubble, deeply frozen, long-lasting thawing sections 9 not exposed to snow, under snow cover. Water and air penetrate the soil through rapid thawing areas. The air spreads along the sides and relieves the vacuum in the permafrost zone that forms in the winter period due to local pressure gradients caused by crystallization of moisture during moisture-vapor transfer. The removed vacuum delays, and in some cases stops, the transfer of capillary moisture during thawing of the soil to lower horizons.

 Example 1. Wheat was harvested, leaving stubble strips of various heights 6 m wide. For this, the cutting height was set at 20 cm for half of the combines, and 10 cm for the other half and during operation. At the beginning of melting, the soil was exposed from the snow cover across the left stubble bands. The width of the soil strips exposed from the snow cover was 3 m, and the width of the non-exposed strips was 20 m.The average soil moisture reserve in the month of May was 40 mm, while in a field with ordinary stubble, but early spring soil exposure was 21 mm.

 Example 2. Conducted harvesting wheat leaving stubble strips of different heights. The width of the strips was 20 m. The cutting height was set at 15 cm for half of the combines, and 20 cm at the other half. At the beginning of snow melting, strip outcrop of the soil from the snow cover across the left stubble strips was carried out. The width of the soil strips exposed from the snow cover was 4 m, and the width of the non-exposed strips was 10 m. The average soil moisture reserve in the month of May was 43 mm, in a field with uneven stubble without spring outcrop 16 mm, and in a field with equal stubble and early spring exposure of 19 mm.

 An increase in stubble bands more than 20 m leads to a decrease in their snow accumulation and, in addition, the atmospheric air that has penetrated into the sub-permafrost zone does not have time to remove the vacuum under them due to the difference in the time of thawing of the strips, as a result of which the soil moisture decreases.

Claims (1)

 A method of preserving soil moisture reserves, including the creation of uneven stubble strips during the harvesting period and early spring strip outcrop of the soil from the snow cover with a width of exposed strips of 3 to 4 m and non-exposed strips of 10 to 20 m wide, characterized in that the strip outcrop of soil from the snow cover is across the strips of the left stubble, while the width of the strips of uneven stubble is selected from the calculation of 6 - 20 m

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