Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower concentrations of minerals such as Mg, Fe, and Cu ...

Stable isotopes in water have the potential to diagnose changes in the earth's hydrological budget in response to climate change and land use change. However, there have been few measurements in the vapour phase. Here, we present high-frequency measurements of oxygen isotopic compositions of water vapour (delta(v)) and evapotranspiration (delta(ET)) above a soybean canopy using the tunable diod...

Agroforestry has been widely practiced in the Loess Plateau region of China because of its prominent effects in reducing soil and water losses, improving land-use efficiency and increasing economic returns. However, the agroforestry practices may lead to competition between crops and trees for underground soil moisture and nutrients, and the trees on the canopy layer may also lead to shortage o...

Crop growth models can be useful tools in evaluating the impacts of di€erent tillage systems on the growth and ®nal yield of crops. A tillage model was incorporated into CROPGRO-Soybean and tested for conditions in Ames, IA, USA. Predictions of changes in surface residue, bulk density, hydraulic conductivity, runo€ curve number, and surface albedo were consistent with expected behaviors of thes...

Functional-structural plant modeling and plant phenotyping require the measurement of geometric features in specimens. This data acquisition is called plant digitizing. Actually, these measurements are performed manually, in invasive or even destructive ways, or using expensive laser scanning equipment. Computer vision based 3D reconstruction is an accurate and low cost alternative for the digi...

Soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae), is a severe pest of soybeans in North America. Soybean aphid populations cycle between a secondary summer host, where populations reproduce parthenogenetically and a primary host, where populations overwinter as eggs. In North America, the secondary host is soybean, and the primary hosts are Rhamnus cathartica L. (Rhamnaceae) and R...

Soybean (Glycine max Merr.) is the world's most widely grown leguminous crop and an important source of protein and oil for food and feed. Soybean yields have increased substantially throughout the past century, with yield gains widely attributed to genetic advances and improved cultivars as well as advances in farming technology and practice. Yet, the physiological mechanisms underlying the hi...