When woody plant abundance increases in grasslands and savannas, a phenomenon widely observed worldwide, there is considerable uncertainty as to whether aboveground net primary productivity (ANPP) and ecosystem carbon (C) and nitrogen (N) pools increase, decrease, or remain the same. We estimated ANPP and C and N pools in aboveground vegetation and surface soils on shallow clay and clay loam so...

Plants activate local and systemic defence mechanisms upon exposure to stress. This innate immune response is partially regulated by plant hormones, and involves the accumulation of defensive metabolites. Although local defence reactions to herbivores are well studied, less is known about the impact of root herbivory on shoot defence. Here, we examined the effects of belowground infestation by ...

The objectives of this study were to evaluate the effects splitting application 30 kg N ha-1 on growth, yield and economics soybean (Glycine max var. Dea-won) in semi-arid sub-tropical Afghanistan. Besides no-N-fertilization control, urea (30 ha-1) was applied fields four-splits: S1, one time basal at sowing; S2, two-splits 50% sowing 10 DAS (days after sowing); S3, three-splits 33% sowing, 20 ...

The aboveground growth, physiological and biochemical parameters of two clones of the cosmopolitan wetland grass Phragmites australis, grown at four treatment combinations of temperature and CO2, were investigated to elucidate whether their climate response differed due to inherent differences in their ecological adaptation. The two phylogeographically distinct P. australis clones (DK clone, Eu...

In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary fo...

We study the power conservation and disseminating reliability problem in precision agriculture applications in this paper. Precision agriculture needs to accurately evaluate farming environment, and soil monitoring is an important part of this effort. Soil measurement requires soil sensors being buried deep enough so as to avoid plowing and other mechanical activities. Due to dielectric loss, r...

Based on regional-scale studies, aboveground production and litter decomposition are thought to positively covary, because they are driven by shared biotic and climatic factors. Until now we have been unable to test whether production and decomposition are generally coupled across climatically dissimilar regions, because we lacked replicated data collected within a single vegetation type across...

Soil seed bank composition is important to the recovery of natural and semi-natural areas from disturbance and serves as a safeguard against environmental catastrophe. White-tailed deer (Odocoileus virginianus) populations have increased dramatically in eastern North America over the past century and can have strong impacts on aboveground vegetation, but their impacts on seed bank dynamics are ...

Zhou, Xiaoping; Hemstrom, Miles A. 2009. Estimating aboveground tree biomass on forest land in the Pacific Northwest: a comparison of approaches. Res. Pap. PNW-RP-584. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 18 p. Live tree biomass estimates are essential for carbon accounting, bioenergy feasibility studies, and other analyses. Several m...

Currently, forests in the northeastern United States are net sinks of atmospheric carbon. Under future climate change scenarios, the combined effects of climate change and nitrogen deposition on soil decomposition, aboveground processes, and the forest carbon balance remain unclear. We applied carbon stock, flux, and isotope data from field studies at the Harvard forest, Massachusetts, to the F...