Frameshift mutation (illustration). This type of mutation occurs when the addition or loss of DNA bases changes a geneâs reading frame. A reading frame consists of groups of 3 bases that each code for one amino acid. A frameshift mutation shifts the grouping of these bases and changes the code for amino acids.
Key points. 1  Soil fertility depends on three major interacting components: biological, chemical and physical fertility. 2  Soil organisms improve soil fertility by performing a number of functions that are beneficial for plants. This article examines six of these functions. Some management practices may help improve and maintain the biological fertility of soil. Releasing nutrients from organic matter. Soil microorganisms (figure 1) are responsible for most of the nutrient release from organic matter. When microorganisms decompose organic matter, they use the carbon and nutrients in the organic matter for their own growth. They release excess nutrients into the soil where they can be taken up by plants.
Biological factors. Plants, animals, micro-organisms, and humans affect soil formation. Animals and micro-organisms mix soils and form burrows and pores. Plant roots open channels in the soils. Different types of roots have different effects on soils.Grass roots are âfibrousâ near the soil surface and easily decompose, adding organic matter.Taproots open pathways through dense layers.lant roots open channels in the soils. Different types of roots have different effects on soils. Grass roots are âfibrousâ near the soil surface and easily decompose, adding organic matter. Taproots open pathways through dense layers.