Topsoil Compositon
A soil's composition encompasses its inorganic(mineral) and organic chemical components.
The organic components include the many life-forms that inhabit the soil.
Inorganic Components
The surface charges of soil particles determine their ability to bind many nutrients.
Most soil particles are negatively charged. Positively charged ions (cations)-such as potassium(K+),calcium(Ca2+),
and magnesium (Mg2+)-adhere to these particles and are therefore not easily lost by leaching, the percolation of water through the soil.
Roots, however, do not absorb mineral cations directly from soil particles; they absorb them from the soil solution.
Mineral cations enter the soil solution by cation exchange, a process in which cations are displaced from soil particles by other cations,particularly H+.
Therefore, a soil's capacity to exchange cations is determined by the number of cation adhesion sites.
ผมพยายามทำให้ดูอ่านง่ายๆนะครับ จริงๆผมแปลไปบ้างแล้วบางประโยค แต่มันมีหลายประโยคที่แปลไม่ออกจริงๆ ก็เลยพิมพ์ไปทั้งหมดเลย
ขอบคุณนะครับ