More information on the Open Book is available. Copyright 1993, the National Academy Press. Keywords, machine extracted. Top 50 words repeated twice, next 100 once, plus phrases. Ephemeral rills will collect water during heavy rains and increase the severity of erosion.
Eutrophication causes algal blooms, fish kills, and other water quality problems.
Two main methods for ensuring fertility are biological nutrient cycling and the addition of chemical fertilizers. Soil management can have a significant impact on green- house gas concentrations inasmuch as soils can be sources or sinks of greenhouse gases. Halophytes can be irrigated with reused drainage water that is higher in salinities. The amount of labile carbon in the soil has an important effect on soil biological activities such as mineralization of nutrients, generation of soil structure, and specific enzyme activities. Salt water in the root zone decreases the osmotic potential of the soil solution relative to the osmotic potential of the root, thereby reducing the amount of fresh water available to plants.