How soil pH effect on the availability of nutrients?

Answer 1

Soil pH Effects on Nutrient AvailabilityIt is critical for growers to have a clear understanding about factors affecting micronutrient availability and pH. Organic soils within the EAA formed as oligotrophic wetlands, meaning that most nutrient concentrations were commonly deficient for growth of plants other than the native vegetation. Micronutrients are mineral elements needed by plants in small quantities. Small variations from the optimum levels required for plant growth can be damaging and stunt growth and reduce yields. This deficiency is readily observed for phosphorus and micronutrients, such as manganese, copper, and zinc. Early research has shown that application of these nutrients as fertilizers significantly increased crop growth and yield. However, rates of fertilizer application that historically produced a crop response have increased with time, corresponding with decreasing soil depth and increasing soil pH.

Nutrients in soil are strongly affected by soil pH due to reactions with soil particles and other nutrients, so in fact the availability of many nutrients has been determined as a function of soil pH. At the original pH of muck soils, total concentrations of phosphorus and micronutrients were too low to support crops, thus the need for supplemental fertilization. Most micronutrients and P are readily available to crops at low pH values, but P and micronutrient availability are optimal at pH values below the current pH of most muck soils. The problem is not so much that total nutrient concentrations are low but rather their availability to plants is too low. Although micronutrients differ somewhat in the response to pH, all show decreased availability with increasing pH at values commonly observed in most muck soils. Thus, the muck soils are increasingly developing conditions where most applied fertilizer nutrients are being made less and less available to crops.