Soil Fertility: Concepts & Ideas

General Soil Fertility Concepts and Ideas

Production of high yielding quality cotton lint requires management of many different production practices including insect management, water management, disease management, and fertility management among others. Each of these production factors, if not managed properly, may lead to limiting yield and quality of the cotton crop. Soil fertility as it relates to cotton production involves managing nutrient levels in the crop and in the soil to ensure optimum production of high quality lint while still maintaining an economic and environmental balance. This is not always an easy task in that several factors including soil moisture, soil chemical and physical characteristics, and general crop health all impact nutrient uptake and utilization by the crop. In order to effectively manage the crop and soil fertility components of a cropping system a basic understanding of soil-plant relationships is important.

Soil-Plant Relationships

Plants may take up nutrients from varying sources including the atmosphere and the soil. However, the majority of nutrients required by a cotton crop are derived from the soil. With the exception of oxygen (O), carbon (C), hydrogen (H), and small quantities of nitrogen (N) and sulfur (S) the primary mechanism of nutrient uptake is through absorption through the root system. Therefore proper management of nutrient levels in the soil is critical to maintaining adequate nutrient levels in the plant for optimum production of lint. Mineral nutrients derived from the soil are absorbed through the root system and carried throughout the plant via the vascular system and the transpiration stream. Since uptake of these nutrients is largely driven by the movement of water from the soil to the plant root systems and throughout the plant, proper soil-plant water relations are critical to maintaining proper crop nutrient status. Extremes in soil water content may result in a disruption of normal nutrient uptake and may result in nutrient deficiencies despite the adequate presence of the mineral nutrients in the soil. Extreme dry soil conditions prevent uptake of nutrients due to the lack of movement of these nutrients toward the root system via the transpiration stream. The solubility of the mineral nutrient also is decreased under dry soil conditions. Conversely, under extreme wet or waterlogged conditions the chemical properties of the nutrient may be altered, preventing uptake by the plant. Maintaining proper soil-plant moisture conditions is an essential part of maintaining good soil fertility and crop nutrient status.