tragacanth gum is one of the most important medicinal and industrial productsof rangelands and is obtained from the incision of gum tragacanth-producing astragalusincluding astragalus keyserlingii. the conservation of astragalus species in rangelandshas a special place in terms of economic profit and soil conservation. the increase in priceof gum tragacanth in recent years and more attention of...

Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers' decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventi...

THREE and a half centuries ago Francis Bacon said "I take all knowledge to be my -sphere." Though competent scholars state that Bacon was far from having full knowledge of the science of his day, his aspiration was not ridiculous or even particularly remarkable in his time, and had he given to science half the time he devoted to statecraft he might well have mastered all the science that was th...

9 7 8 9 2 2 1 2 6 8 1 2 3 IL O -U N C TA D S H A R E D H A R VE S TS : A gr ic ul tu re , Tr ad e, a nd E m pl oy m en t Agriculture employs more than a billion people in developing countries, representing 48 per cent of the developing-country labour force. This book analyses how agricultural trade affects labour markets in developing countries and in particular what it implies for the creation...

One of the most effective micronutrients on the quantity and quality of medicinal herbs is zinc (Zn). The present study aimed to assess the impact of the foliar application of various Zn sources (0.2% w/v) including Zn chelated by amino acid (ZnAAC), Zn-sulfate and Zn-EDTA on qualitative and quantitative features of Lemon verbena (Lippia citriodora L.). In two harvests, the field experiment was...

The objective of this study was to evaluate the genotypic stability of agronomic traits in hybrids of Panicum maximum. Hybrids originating from the crosses between two sexual parents and cultivars Mombasa and Tanzania were evaluated in an incomplete-block design. Evaluated traits were total dry matter, leaf dry matter, stem dry matter, percentage of leaves, and leaf:stem ratio. These traits wer...

The concepts of sustainable original harvest (SOH) and sustainable disturbance harvest (SDH), and simple indices such as the ratio of successive harvests do not provide a reliable indication of the sustainability of a harvest. Some limitations of these concepts are illustrated in the context of selection harvesting of timber from natural forests. Four models are used to demonstrate that maintai...