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A soil test is a laboratory or in-situ analysis to determine the chemical, physical or biological characteristics of a soil. Possibly the most widely conducted soil tests are those performed to estimate the plant-available concentrations of nutrients in order to provide fertilizer recommendations in agriculture.
Total Kjeldahl nitrogen or TKN is the sum of nitrogen bound in organic substances, nitrogen in ammonia (NH 3-N) and in ammonium (NH 4 +-N) in the chemical analysis of soil, water, or waste water (e.g. sewage treatment plant effluent).
The Illinois Soil Nitrogen Test ("ISNT") is a method for measuring the amount of Nitrogen in soil that is available for use by plants as a nutrient. The test predicts whether the addition of nitrogen fertilizer to agricultural land will result in increased crop yields. [1] [2] Nitrogen is essential for plant development.
The C:N ratio of soil can be modified by the addition of materials such as compost, manure, and mulch. A feedstock with a near-optimal C:N ratio will be consumed quickly. Any excess C will cause the N originally in the soil to be consumed, competing with the plant for nutrients (immobilization) – at least temporarily until the microbes die.
Redfield’s analysis of the empirical data led to him to discover that across and within the three oceans and Barents Sea, seawater had an N:P atomic ratio near 20:1 (later corrected to 16:1), and was very similar to the average N:P of phytoplankton. To explain this phenomenon, Redfield initially proposed two mutually non-exclusive mechanisms:
Symbol used in drawings Standard penetration test N values from a surficial aquifer in south Florida.. The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil.
In general, organic matter contacting soil has too little nitrogen to support the biosynthetic needs of the decomposing soil microbial population. If the C:N ratio of the decomposing organic matter is above circa 30:1 then the decomposing microbes may absorb nitrogen in mineral form as, e. g., ammonium or nitrates. This mineral nitrogen is said ...
The Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes soil erosion processes. [1]Erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including: sediment load assessment and inventory, conservation planning and design for sediment control, and for the advancement of scientific understanding.