We have already talked about the problems of reducing forest belts, but mainly about their absence in the agricultural landscape of our country, in one of our articles, to which our readers gave several of their comments and advice. But in the last century there was and began to operate the state "plan for the transformation of nature", according to which a grandiose attack on drought was planned by planting protective forest belts, the introduction of crop rotations and other measures. This topic is quite relevant for Uzbekistan at the present time, and therefore we decided to once again remind about it and present to your attention an article published in one of our past newsletters, which fully reveals the essence of the problem, suggests ways to solve it and leads to the benefits of creating protective forest belts for local natural landscape and agricultural production.

The author in his article answers the main questions of today.

E.K. Botman, Candidate of Agricultural Sciences, Republican Scientific and Practical Center DS and LH

Is there a way to increase the productivity of irrigated land to 15-20% without large investments? There is such a way.

Is there a way to preserve the surface fertile soil layer to preserve the country's crop yields and food security? There is such a way.

Agriculture occupies a significant share in the economy of Uzbekistan. The basis of agriculture, and, consequently, of the country's food security, is irrigated agriculture. But irrigated arable land in the arid zone is an artificially created ecosystem that is not capable of self-regulation to maintain a constant level of soil fertility and therefore needs environmentally sound management decisions.

Problem

Wind erosion is one of the main factors in the loss of the upper fertile soil layer and the loss of productivity. You need to know and be able to prevent two important negative properties of winds:

First, the air / wind temperature does not matter, but if a strong wind blows in the spring after plowing, it will quickly dry out the soil disturbed by plowing. When the plowed soil dries up, its structure changes, fine particles appear, which rise from the surface by the wind. There is blowing out, loss of the upper, most fertile soil layer. The same can happen with the plowed land after harvesting grain in summer - fields that are not covered with vegetative cover after harvesting wheat are also exposed to the hot wind and the fertile soil layer is lost / blown out.

Second, summer winds with low air humidity and high temperatures harm crops in other ways. In cotton, for example, during dry wind, fruit elements can fly around, i.e. buds, flowers, young ovaries. It is clear that this is a direct loss of yield. In cereals from such winds, there is a fuse of grain, i.e. it will be incomplete.

More than 65% of the irrigated arable land in our country is subject to varying degrees of wind erosion. In recent years, the humus content in soils has decreased by 30-50%. About 40% of the area of all irrigated land is occupied by soils with a very low humus content (up to 1.0%). As a result, more and more irrigated lands go out of agricultural use due to the reclamation state.

Solutions

One of these most effective approaches to combating wind erosion and improving the microclimate of fields is the creation of systems of forest shelter belts.

The name itself speaks for itself - "forest shelter belts", i.e. strips of several rows of trees and bushes that protect the fields. The forest belts reduce the wind speed in the inter-lane space, i.e. on protected fields. A decrease in wind speed affects all other microclimatic parameters of the territory - air humidity, air and soil temperature, etc.

Strip forest plantations on irrigated lands (by the way, rainfed ones too) have a number of advantages, including:

1. They increase the yield of agricultural crops - The increase in yield reaches up to 15-20%, while the quality of the crop, in particular the length of the fiber, also increases. This is due to the improvement of microclimatic conditions on the protected fields:

• a decrease in wind speed reaches 38 - 34%, which leads to an increase in the moisture content of the surface air layers up to 5-9%;

• decrease in air temperature in summer to 10C, and soil temperature to 1.20C;

• lower water stress, improved moisture content in the soil and lower temperatures create more favorable conditions for the existence of soil microorganisms, improving soil fertility and thereby providing favorable conditions for the growth and development of agricultural plants.

2. Stopping the loss of the top fertile soil layer - Reducing the wind speed on the protected fields leads to the cessation or significant reduction of wind erosion of the soil, that is, stops the blowing out of the top most fertile soil layer.

Such "living" giants are able to do their job even in winter.

3. Regulation increase in the level of mineralized groundwater - Crowns of trees through the foliage in the summer evaporate a huge amount of water pumped from the ground. Trees act as a kind of pump, pumping out groundwater with their roots and evaporating its foliage. This results in biological drainage, which reduces the level of saline groundwater, and, consequently, reduces the likelihood of secondary soil salinization. Considering that more than half of the irrigated lands in our country are subject to secondary salinization due to the high level of saline groundwater, this is a very important property.

These are the main benefits of forest belts that are important to farmers. There are a lot of additional qualities that speak in favor of the creation of shelterbelts, namely:

• Purify the air - Tree plantations trap huge amounts of airborne dust on their foliage, thus purifying it. In addition, most trees, in particular poplars, secrete phytoncides from their foliage that kill pathogens;

• Aesthetics - Forest plantations diversify the monotonous landscape of agricultural fields, significantly increasing its aesthetic appeal;

• Place for recreation - Often, forest plantations in oases are the only place suitable for recreation for the local population;

• Wildlife Habitat - In the monotonous agrarian landscape of agricultural fields, forest stands are sometimes the only refuge for wildlife, a hotbed of natural biodiversity (birds, insects, small mammals, etc.). And from the science of Ecology it is known that the more diverse the ecosystem, the more stable it is;

• Carbon Sinker - Trees feed on carbon by absorbing carbon dioxide from the atmosphere. They thereby help regulate the global climate system. Calculations show that 1 hectare of forest plantations absorbs about 4.48 tons of carbon annually, which corresponds to 16.43 tons of CO2 per hectare per year. With an average service life of protective forest belts of 30 years, the potential for carbon dioxide absorption by protective plantations on irrigated arable land in Uzbekistan can be estimated at 16.43 t * 30 years = 492.9 t CO2;

• Source of wood - Although forest plantations on irrigated land are primarily intended for protective functions, they nevertheless have a lifespan, after which they are subject to felling, stubbing and renewal. By this time, they accumulate a significant stock of wood (500-600 m3 / ha), including business and wood. With significant shortages and high wood prices, this function should also not be discounted;

• Other purpose - In addition to shelter belts in rural areas, other types of forest plantations can be created, which increase the roughness of the earth's surface, and therefore improve the microclimate and habitat of local residents. This, for example, can be specialized forest plantations (mulberries - for feeding the silkworm, poplar and other fast-growing species - for obtaining timber, planting of greenery in settlements, etc.).

Forest belts to protect seedlings

How to create field-protective forest plantations?

Available technologies have been developed to create forest shelter belts. To create them, you need to keep in mind several basic principles for creating such stripes:

1. It is very important that it is a system of interacting strips, and not one or two stripes at the headlands. The system of forest shelter belts means the complete coverage of a certain area with forest belts (1-4 rows) at a certain distance from each other in such a way that the wind-controlling effect of one strip is overlapped by the action of the other strip.

2. The stripes should be located perpendicular to the main harmful winds and these stripes are called main. But, in view of the fact that the wind often changes direction, there must be auxiliary strips that provide protection from winds from other directions. Thus, the system of stripes looks like cells in the form of rectangles (see photo below), the long side of which is the main stripes, and the short side is auxiliary.

3. Scientific research has determined that the higher the strip, the further the range of its influence extends, that is, for the minimum land allotment to the field protection belts, it is necessary to create them from tall-trunked species (poplar, sycamore, elm, ash, willow, etc.). The relationship between the height of the strip and the range of its influence has been established. It is believed that this range is approximately equal to 20-25 times the height (H) of the strip itself, i.e. the spacing should be 20-25H, where H is the height of the strip in meters.

4. By the selection of tree and shrub species and their placement in the strip, its structure is formed - dense, openwork or blown. The design, as well as the height of the strip, determines the range of its influence and some other characteristics of its functional features. Scientific research has determined that for the complete protection of irrigated arable land by a system of field-protective forest floors It is enough to allocate about 3% of its territory, and partly forest belts will be located in the exclusion zones of the irrigation-drainage and road network, that is, they will not occupy productive arable land.

Forest-agricultural landscape with shelterbelts

conclusions

In the 70s - 80s of the last century, there were about 40 thousand hectares of forest shelter belts in Uzbekistan. Now they are practically gone. Unfortunately, recently, new systems of forest shelter belts have not been created, and the old ones have failed due to aging and felling.

There are no forest belts, the fertility of the land has greatly decreased. Of course, we do not assert that the absence of forest shelter belts is the main factor in the loss of soil fertility. There is no one major factor. This is a complex of factors. And the absence of shelterbelts is one of the important components of the loss of fertility.

So,

1. It is necessary to transform the agrarian landscape - only fields (which we have now) into a forest-agricultural landscape (with shelterbelts and other plantings of various functional purposes).

2. It is necessary that the initiators of the creation of systems of forest belts on their lands were the farmers themselves, and not only the state. It is then that there will be the greatest incentive and the greatest efficiency in creating such bands.

3. It is necessary that local government authorities support the initiatives of farmers to create systems of forest belts. Many farmers say that they are not allowed to alienate land for forest belts - all land must be used for crops. As mentioned above, forest belts need no more than 3% along the borders of the fields. But instead, farmers will get a 15-20% yield increase in the protected field. And most importantly, the soil fertility is preserved for future harvests. And this is the most important aspect.

The growth of the population and the tasks of increasing the standard of living, food security of the country require investments in the preservation and increase of soil fertility. The revival of field-protective afforestation in our country leads to the stabilization of the level of soil fertility of irrigated arable land and its qualitative improvement.

The Small Grants Program of the Global Environment Facility (PMGEF) in Uzbekistan is ready to support the initiatives of districts or oblasts to recreate systems of shelterbelts on arable land. For questions and suggestions, please email alexey.volkov@undp.org or call: + 998 71 120 34 62 (work) or + 998 93 381 00 82 (mobile).