ارزیابی پروژه‌های مدیریتی و احیایی بیابان‌زدایی در دشت یزد-اردکان

هدف از این تحقیق بررسی تاثیر پروژه‌های مدیریتی و احیایی بیابان‌زدایی در بهبود برخی شاخص‌های پایداری خاک و ویژگی‌های پوشش گیاهی است. این مطالعه در 4 سایت واقع در دشت یزد-اردکان شامل سایت نهال‌کاری، سایت مدیریت هرزآب، سایت مالچ‌پاشی‌شده و سایت قرق انجام شد. در هریک از سایت‌ها شاخص‌های گیاهی مانند درصد تاج‌پوشش، تراکم، زادآوری و شادابی گونۀ سیاه‌تاغ (haloxylon aphyllum) اندازه‌گیری شد. پس از جمع‌آوری داده‌ها با استفاده از نرم‌افزار spss تحلیل آماری انجام شد. نتایج تجزیه و تحلیل آماری با استفاده از آزمون t مستقل نشان داد که در تمام سایت‌های مطالعاتی ازنظر درصد پوشش گیاهی و تراکم ازنظر آماری در سطح خطای 1% دارای اختلاف معنادارند. همچنین مقایسۀ میانگین بین تیمارها (سایت‌ها) به روش آزمون دانکن نشان داد که میانگین درصد پوشش گیاهی (72/5)، تراکم گیاهی (75/4)، زادآوری (542/0) و شادابی (33/61) به‌عنوان بیشترین میانگین و مربوط به تیمار هرزآب، و میانگین درصد پوشش گیاهی (68/1)، تراکم گیاهی (2)، زادآوری (111/0) و شادابی (24/12) به‌عنوان کمترین میانگین و مربوط به تیمار قرق بود. در سایت مدیریت هرزآب به‌دلیل فراهم شدن نفوذپذیری آب و در دسترس قرار گرفتن رطوبت مورد نیاز برای استقرار و توسعۀ پوشش گیاهی باعث افزایش درصد پوشش و تراکم پوشش گیاهی آن می‌گردد. با توجه به نتایج تحقیق پیشنهاد می‌شود که در پروژه‌های مدیریتی و احیایی بیابان‌زدایی در دشت یزد-اردکان بهترین روش‌ها به‌ترتیب تیمارهای مدیریت هرزآب، مالچ‌پاشی، نهال‌کاری و قرق مد نظر قرار گیرد.

investigating desertification management and rehabilitation projects in yazd-ardakan plain

introduction: the phenomenon of desertification has always been considered as one of the most importantchallenges facing iran, which has been aggravated by human and climatic factors in recent years. therefore, it isnecessary to implement anti-desertification plans and projects set through the development planning to curbdesertification and restore and improve degraded lands. in this regard, the severity of the phenomenon can bedecreased by applying appropriate management solutions and methods and preventing its expansion andprogress. implementing anti-desertification management and rehabilitation projects according to the ecologicalconditions of each region improves the condition of the vegetation, strengthens the soil stability, and protects thesoil from the risks of water and wind erosion. therefore, analyzing different aspects of the anti-desertificationprojects which are planned and carried out by the government is required for improving management in thenatural resources sector. one such measure can be the restoration of desert pastures with regard to unfavorableclimatic conditions. thus, this study set out to investigate the influence of anti-desertification management andrestoration projects in improving soil stability indicators and vegetation characteristics.materials and methods: this study was conducted in four sites located in the yazd-ardakan plain, includingthe seedling site, the water weed management site, the mulched site, and the enclosure site. the main speciesinvestigated in each of these sites was haloxylon aphyllum. to this end, four transects were placed in the site atregular intervals. it should be noted that the transects were placed parallel and perpendicular to each other in flatand sloping areas, respectively. the number of plots on each transect was 15 and the area of the plots was 210cm. moreover, the index plant characteristics such as canopy percentage, density, reproduction, and freshness ofhaloxylon aphyllum species were measured. finally, after collecting the required data, statistical analysis wasperformed using the spss software.results: according to the results of statistical analysis performed via independent t-test, a statistically significantdifference was found in the percentage of vegetation and density at the error level of 1% in all investigated sites.duncan's multiple range test revealed significant differences in mean values among treatments. the treatmentassociated with herbaz exhibited the highest mean values for vegetation cover (72.5%), plant density (75.4),regeneration (542.0), and vigor (33.61). conversely, the treatment subjected to enclosure showed the lowest meanvalues for vegetation cover (68.1%), plant density (2.0), regeneration (111.0), and vigor (24.12).conclusion: compared to the control area, the percentage of vegetation and density of the effective area wassignificant in the seedling site (where the seedling project is based on seedling irrigation), which is due to thelack of suitable conditions and rainfall in the seed establishment. the wastewater management site demonstratedincreased vegetation cover and density due to enhanced water infiltration and readily available moisture, whichfacilitated plant establishment and growth. similarly, the mulched site exhibited higher vegetation cover anddensity compared to the control, attributable to the creation of a subsurface moisture layer beneath the mulch,providing a favorable environment for seed germination and plant development in the enclosure site which isless affected by human changes, the amount of soil erosion and ecosystem destruction is lower than other sites inall dimensions, leading to the higher percentage of vegetation and plant density. the establishment andexpansion of vegetation cover through various methods have been implemented in recent decades as a means tocombat desertification and mitigate the damages caused by dust storms in arid regions. however, water scarcityposes a significant constraint. consequently, it is recommended that, in the context of desertificationmanagement and rehabilitation projects in the yazd-ardakan plain, the most effective approaches be prioritizedas follows: runoff water management, mulching, afforestation, and enclosure.