BIOL 1201 Study Guide - Micronutrient, Nitrogen Fixation, Humus
Document Summary
Soil is the place where much of the plant nutrients occur. Soil is made up of particles derived from the breakdown of rocks (minerals) along with organic material (humus). Two aspects of soil the texture and composition are important for plant growth. Some of the nutrients are needed in large quantities (>1% of the plant"s dry weight), these are the macronutrients (see table 37. 1 note iron is listed as a micronutrient) C, h, o, p, k, n, s, ca, fe, mg. Another group of nutrients is only needed in small amounts (<1% of the plant"s dry weight), these are the micronutrients. Only two of these macro/micronutrients come from the air the remainder are obtained from the soil. This doesn"t mean the plants don"t grow, it means that growth is limited by the supply of these nutrients (see fig 37. 8). Most typical fertilizers supply n, p, and k. Nitrogen fixation: bacteria convert n2 from the atmosphere to nh3.
