the effect of exclosure on the changes of vegetation cover of rangelands of ahmad-abad region located in zanjan province has been studied during 2002 to 2006. three transects comprises of 60 fixed quadrate were establish within exclosure area and outside as well. the changes of vegetation cover were studied to made comparison between the changes of manipulated factors and soil elements using t ...

BACKGROUND AND AIMS Despite general agreement regarding the adaptive importance of plasticity, evidence for the role of environmental resource availability in plants is scarce. In arid and semi-arid environments, the persistence and dominance of perennial species depends on their capacity to tolerate drought: tolerance could be given on one extreme by fixed traits and, on the other, by plastic ...

Relatively little experimental evidence is available regarding how ecological resistance and propagule density interact in their effects on the establishment of invasive exotic species. We examined the independent and interactive effects of neighbour cover (biotic resistance), winter vs. spring water addition (abiotic resistance) and seed density on the invasion of the European perennial grass ...

A nineteen year trial at Lake Tekapo compared the longer term trends of over-drilling legume and grasses into either previous undeveloped tussock country or following a previous legume phase. Tall oat grass (from summer sowing) and cocksfoot (from spring sowing) were the most successful of the sown grasses. They remained a low proportion of the swards but greater with prior herbicide treatment,...

A significant portion of the irrigated acreage in the intermountain western U.S. is comprised of cool season grass pastures. Droughts, coupled with increasing demands for limited water supplies in the region, have decreased the water volumes available for irrigating these pastures and other crops. Consequently, relationship between crop yield and irrigation (water production functions) should b...

A systematic review and meta-analysis were used to assess the current state of knowledge and quantify the effects of land use change (LUC) to second generation (2G), non-food bioenergy crops on soil organic carbon (SOC) and greenhouse gas (GHG) emissions of relevance to temperate zone agriculture. Following analysis from 138 original studies, transitions from arable to short rotation coppice (S...