PO 12. Describe how the following soil characteristics affect ntrient uptake.

pH affects nutrient availability by changing the nutrient form.  For instance, the different forms of N (affected by pH) have different leaching capabilities; other nutrients may become adsorbed or desorbed, precipitated, mineralized, or immobilized at different pH values.  Many nutrients are more available in slightly acid soils: P is most available at a neutral pH (about 6.5); Mb is available at high pH and can be toxic to plants.  The pH is also important in N transformations, such as mineralization, nitrification, and N fixation, as the bacteria involved are pH-sensitive.

Temperature affects the plant's ability to grow, and thus affects nutrient uptake.  Ideal temperatures vary by plant species and cultivar.  The soil temperature also influences microbial activity, an important part of organic material decomposition.