Information on How Different Types of Soil Affect the Growth of a Pinto Bean

Clay Soils

• Clay soils are one of the main four texture classes of soil. Compared with silty soils, loamy soils or sandy soils, clay has the finest particle size. This makes clay a soil with very extreme characteristics. When exposed to water, clay will become very sticky and plastic. The water droplets easily fit within the many tiny pores of air within clay soil. However, clay soil's fine network of air pockets and soil particles does not allow water to escape easily. Therefore, clay soils retain water, threatening many plants, including pinto beans, by waterlogging their roots and denying them sufficient air. This can lead to root rot as well as essentially asphyxiating the plant.

Loam Soils

• Loam soils stand out from clay, silt or sand soil textures, which are defined by their progressively larger particle size. In contrast, loam soil doesn't have a uniform particle size. Instead, it consists of a balanced admixture of the other soil types, mixed with high levels of organic material. Therefore, loamy soil tends to be rich in minerals and fertilizing material, such as decomposed vegetation or manure. For pinto beans, loamy soils are extremely beneficial, providing for the plants' nutritive needs. In addition, loamy soil is typically well draining, letting plentiful water reach the plant roots but allowing excess water to filter to lower depths easily. Finally, loams are well aerated, as the mixed particle and pore size can accommodate both water and air droplets. For optimal growth, plant pinto beans in slightly sandy loam soils, as they prefer slightly drier, faster-draining soil than average.

Nitrogen and Phophorus-Rich Soil

• Texture isn't the only means of classifying soil. A soil's mineral content also dramatically affects pinto bean growth. Soils that have high levels of nitrogen and phosphorus will contribute to higher yields and beans of better quality. While some soil types will naturally demonstrate these characteristics, you can easily modify a soil's nutrient content by judiciously adding fertilizer. Use the fertilizer's ratio of nitrogen, phosphorus and potassium (the NPK ratio) to determine how it will affect your soil and the plants growing there.