Land degradation takes a number of forms, including depletion of soil nutrients, salinization, agrochemical pollution, soil erosion, vegetative degradation as a result of overgrazing, and the cutting of forests for farmland. All of these types of degradation cause a decline in the productive capacity of the land, reducing potential yields. Farmers may need to use more inputs such as fertilizer ...

Supervisory Soil Scientist, Rocky Mountain Forest and Range Experiment Station, Tempe, Arizona; and Soil Microbiologist, Pacific Southwest Forest and Range Experiment Station, Glendora, California. The weathering of parent rock may be an important source of some nutrients. The rates of weathering of the different parent rock materials vary and affect the inherent fertility and productivity of a...

Soil-dwelling insects commonly co-occur and feed simultaneously on belowground plant parts, yet patterns of damage and consequences for plant and insect performance remain poorly characterized. We tested how two species of root-feeding insects aff ect the performance of a perennial plant and the mass and survival of both conspecifi c and heterospecifi c insects. Because root damage is expected ...

Arid ecosystems are characterized by high spatial heterogeneity, and the variation among vegetation patches is a clear example. Soil biotic and abiotic factors associated with these patches have also been well documented as highly heterogeneous in space. Given the low vegetation cover and little precipitation in arid ecosystems, soil microorganisms are the main drivers of nutrient cycling. None...

—We conducted a pot experiment examining the effects of simulated leaf herbivory and supplemental soil nutrients on extrafloral nectary (EFN) glands of Sapium sebiferum seedlings derived from native Chinese and invasive Texas seed stock. We predicted that simulated herbivory and increased soil nutrients would increase EFN activity. We also predicted that Chinese genotypes would have greater EFN...

Without exogenous rock-derived nutrient sources, terrestrial ecosystems may eventually regress or reach a terminal steady state, but the degree to which exogenous nutrient sources buffer or slow to a theoretical terminal steady state remains unclear. We used strontium isotope ratios (Sr/Sr) as a tracer and measured Sr/Sr values in aeolian dust, soils, and vegetation across a well-constrained 3M...

The amendment of soil with biochar has been demonstrated to have an effect not only on the soil physicochemical properties, but also on soil microbial community composition and activity. Previous reports have demonstrated significant impacts on soil microbial community structure. These impacts are modulated not only by the biochar composition, but also on the soil’s physicochemical characterist...