Introduction

Whenever we are studying an important crop plant such as cotton, it is a natural tendency to focus on the above ground portions of the plant, because that's where the bolls are. However, an equally important part of the plant is the root system, which is hidden from view and totally immersed in the soil. The soil provides all of the mineral nutrition, water, and mechanical support to the plant through the root system, and therefore is a vital link to the health and productivity of any cotton plant. The soil is a focal point of any farming operation. At the beginning of each season, growers use various tillage operations to incorporate residues from previous crops and to prepare an adequate seedbed for the subsequent crop. As a result, most farmers are very familiar with their fields in terms of surface soils, where and how the textures change (i.e. clayey, sandy, or rocky areas) and what is required to till them properly. Most of us working in the field also notice that despite the excellent soil maps and surveys available to us, which provide general descriptions of soils we encounter in a given field, the most detailed mapping of the soils in that field will be performed by the (cotton) plants. For example, areas of a field with better soils will produce better plants, and vice versa. An excellent time to make note of this is during harvest. When you are riding a picker through the field you have an excellent vantage point from which to map the soils in the field, from strong to weak. In dryland areas this may be from a hilltop to a side-slope to the bottom of a swale in a field. In the irrigated west it may be from areas which were cut or filled in during the process of land leveling, or from the presence of coarse soils which are remnants of old washes that passed through the area before cultivation.

In this article we will discuss various aspects of soil evaluation including physical examination, soil sampling and analysis, and soil test interpretation. We will also discuss how these approaches to soil evaluation can be incorporated into both short- and long-term management plans.

Soil Evaluation

Soil Sampling - Collecting the Sample

Soil Testing for Cotton Production

Interpretation of Soil Test Results

Developing a Soil Management Plan