A soil test is a process by which elements (phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper and zinc) are chemically removed from the soil and measured for their "plant av READ MORE http://www.ncagr.gov/cyber/kidswrld/plant/soiltest.htm
The aim of this resource list is to provide a range of soil testing labs and supplies that support the special analytical needs of farmers using organic or sustainable production methods. Fundamentall READ MORE http://www.attra.org/attra-pub/soil-lab.html