مهار بيابان‌زايي

۴.                 Research and achievements:

Although, several organizations such as Tehran University Desert Research Centre of Iran, Oil Research Institute, Management and Programming Organization as well as several other higher education centres are active in this regard and have already implemented or are in the process of implementation of projects, but the achievements of Forests and Rangelands Research Institute as the main responsible institute regarding the conduction of plans and policy making of future plans will be explained briefly.

Generally, the research programmes which practically started with “Eroded rangelands improvement by assessment of cultivation season, sowing depth and the amount of seeds of dryness resistant range plants to be sown” in 1966[1], can be briefed in 7 groups: identification of the main soil and water resources, biological fixation of sand dunes, physical fixation of sand dunes, productivity and exploitation of deserts and barren lands, conservation of Saxaul and Tamarisk tree forests, consistency plans, and reclamation of arid and vulnerable lands.

The most important responsibility of the first group (identification of the main soil and water resources), have been provision of a base for identification of main critical regions of the country and the most important factors, affecting land productivity decline. The feedbacks of this group provide a great substantial and applied assistance to the planners and raise the level of success of the development plans. In this way not only the national resources are being conserved but also the declination of vulnerable environments of the country can be reduced. In this regard the achievements of this group are:

·        Identification of the ecological needs of some indigenous plants of dry zones in the country;

·        Maximum research efficiency assessment of the country in preparation of desertification maps by FAO and UNEP methods and information efficiency assessment according to 9 desertification factors;

·        Discovering the fact that the raise and reduction of soil salinity in Central parts of Iran, are often the result of transformation of soils salinity from medium to high;

·        Preparation of 32 morphometric maps of Gorgan-Rood watershed and efficiency assessment of watersheds slope measurement mechanical methods in comparison with other watersheds;

·        Discovering the fact that during 17 years of a 40 year period the central watershed of Iran enjoyed a relatively favorable climatic condition and during the rest 23 years had a tendency towards low to medium level desertification;

·        Discovering the most important factor for water resources quality decline of Salt Lake (Namak Lake) watershed;

·        Introduction of effective factors on soil granules consistency;

·        Discovering the fact that during a 30 year period, in most of the times the permanent flow of the rivers of Central watershed have been less;

·        Discovering the fact that 86.5 percent of the Northern Khorasan undergoes different levels of desertification and plantation coverage decline, with 46 percent and wind erosion with 5 percent have the maximum and minimum effects respectively, on the occurrence of this critical situation.

The main goal of the second group (biological fixation of sand dunes), is to find the most practical and simple way for controlling the movements of active sand dunes in dangerous and vulnerable regions of the country by taking advantage of plant species with minimum ecological needs and ideal for dry regions. The most important achievements of this group are:

·        Specifying the best time and place for plantation of Lotus tree specie in sand dunes of Khuzestan province;

·        Specifying sowing best time, spacing, size and age of seedlings and saplings           of                    ,saxaul and tamarisk trees in sand dunes of Sabzevar and Khuzestan;

·        Specifying the best method for Tamarix tree seed and seedling cultivation;

·        Specifying 80 centimeters as the best dibbling depth for sowing Tamarix, saxaul, Atriplex and Euphrates poplar trees;

·        Comparing the quality of pots for growing seedlings used in Sabzevar and Khuzestan, and suggesting plastic pots.

The plans of third group (physical fixation of sand dunes) were considered as applied-administrative. On the other hand the group tries to reduce the implementation costs of the desertification control plans and raise the success percentage. The following achievements are the main outcomes of the implementation of the said plans:

·        Selection of the most proper height and spacing for windbreaks to be used in Khuzestan province and comparison between windbreaks constructed in Khuzestan and Northern Khorasan (Sabzevar);

·        No mechanical structures construction in marn and vulnerable land;s

·        Calculation of the specific amount of runoff water current in lands with or without mulch coverage;

·        Resistance comparison of the clay, cement, lime and mixed mulches

·        Cost estimation of mechanical ecological methods and oil mulching

The most important outputs of the fourth group (productivity and exploitation of deserts and barren lands) are:

·        Recognizing advantages and disadvantages of cultivating market garden products in sand dunes;

·        Using pitcher irrigation for disposition of seedlings and windbreaks;

·        Pruning of Saxaul trees and recommending the use of the seeds as animal feed

In fact, several problems were brought forth after the extensive administrative action taken in a large area of deserts of the country during the past half a decade that this group came to existence to find solutions for these problems by the order of the relevant administrative organization.

The achievements of fifth group (conservation of Saxaul and Tamarisk tree forests) are as follows:

·        Successful cultivation of Sansevieria specie in desert environments of Central Iran;

·        Understanding the causes of Saxaul and Tamarix trees wilting and providing practical solutions to return lushness to the plants;

·        Comparison of the effects of different pruning methods;

·        Specifying the sand dunes height critical limit for the plantation coverage

It seems that the existence of the said plans was according to the needs of the administrating organizations.

The most important achievements of sixth group (consistency plans) are:

·        To find out the level of consistency of indigenous and exotic species appropriate for the different arid zones of the country;

·        Introduction of the most appropriate species for sand dune fixation purpose.

It seems that the main goal for existence and extension of these plans was to find ways for realization of the dream of “verdure deserts”; a goal that has lost its priority today and no urgency is felt for reaching it. However, in certain regions and for maximum exploitation of the sustainable potentials of the lands, the limited continuation of such plans is suggested.

            Finally a greatest volume of research has been implemented by seventh group (reclamation of arid and vulnerable lands) and some of the most important achievement and feedbacks of the forestation department depend on the activities of this group. For example:

·        Introducing “water table management or Abkhandary”, a simple and low cost, local method for flood control and returning life to the environments threatened by desertification

·        Finding out the Yazd-Ardakan sand dune extension reasons and their movement direction;

·        Suggesting integration and coordination of watershed management and sand dune fixation activities in Masileh watershed with the purpose of biological fixation of Tarsib area;

·        Suggesting to use plastic mulches in forestation and farming practices because of considerable reduction in water use;

·        Suggesting that the use of permeable polymers is not economical.

[1] Forests and Rangelands Research Institute Journal, No. 5 (Peymanifard and Tariqi, 1972)