soil alkalinity and salinity are serious problems in arid and semi-arid regions, and therefore monitoring of soil ph and electrical conductivity (ec) is necessary in any region. the present study aimed to properly interpolate soil ph and ec as soil quality indices in a semi-arid mountainous area with annual precipitation of 342.4 mm. the study area is the karimabad rangelands in hamadan provinc...

The effects of hydrogen ion concentration on plant growth occupy a prominient position in discussions of the adaptability of plants to their nutrient eiivironmelit. In the last two decades, with the improvements of methods of measurinig pH and particularly with the widespread adoption of the (lass eleetrode, increasing attention has been given to the hydrogen ion coneenitrationi in soils as it ...

Extracellular enzymes are the proximate agents of organic matter decomposition and measures of these activities can be used as indicators of microbial nutrient demand. We conducted a global-scale meta-analysis of the seven-most widely measured soil enzyme activities, using data from 40 ecosystems. The activities of beta-1,4-glucosidase, cellobiohydrolase, beta-1,4-N-acetylglucosaminidase and ph...

Improvement of phosphorus circulation in the soil is necessary to enhance phosphorus availability to plants. Phosphorus circulation activity is an index of soil's ability to supply soluble phosphorus from organic phosphorus in the soil solution. To understand the relationship among phosphorus circulation activity; bacterial biomass; pH; and Fe, Al, and Ca concentrations (described as mineral co...

Soil pH may influence speciation and extractability of Pb, depending on type of vegetation in urban soil environments. We investigated the relationship between soil pH and Pb extractability at forest and turf grass sites in Baltimore, Maryland. Our two hypotheses were: (1) due to lower pH values in forest soils, more Pb will be in exchangeable forms in forested than in turfgrass soils and (2) d...

There is increasing recognition of the importance of niche optima in the shift of plant-plant interactions along environmental stress gradients. Here, we investigate whether deviation from niche optima would affect the outcome of plant-plant interactions along a soil acidity gradient (pH = 3.1, 4.1, 5.5 and 6.1) in a pot experiment. We used the acid-tolerant species Lespedeza formosa Koehne as ...