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This article presents research on evaluating problem-based learning using GIS technology in a Singapore secondary school. A quasi-experimental research design was carried to test the PBL pedagogy (PBL-GIS) with an experimental group of students and compare their learning outcomes with a control group who were exposed to PBL but not GIS. The results show significant differences in the learning outcomes between the two groups. Specifically, students in the control group show more memorization skill while students in the experimental group demonstrate more analytical and evaluation skills. The conclusion is that learning with PBL-GIS pedagogy can result in higher-order learning outcomes. (Contains 2 figures and 4 tables.)

A study of the influence of various root length densities Lr on corn (Zea mays L. ) during vegetative preanthesis and anthesis plant growth phases of interrill soil erosion was conducted to determine rainstorm simulations in a 1 by 1 m plot of Cecil sandy loan. Interrill erosion from a moldboard-plowed Cecil sandy loan was not lowered by high density of live cort roots.

The amount of rain that reaches the soil is determined by rain throughfall and stemflow. Stemflow is the amount of rain water intercepted and funneled through plant stalks to the roots. A studyn was conducted to compare the eficacy of stemflow and leaf dripsfor corn and sorghum. Generated data show that corn stemflow is greater than that of sorghum due to morphological variability but sorghum stemflow appeared to promote infiltration better than corn. The ratio of sediment to runoff was not influenced by canopy type but corn canopy proved to be more efficient at minimizing soil erosion caused by throughfall.

Abstract Where map legends and map unit definitions reflect the mental models used by soil surveyors to map soils in the past, the association between soil map units and other [...]