|
Cotton is able to thrive in marginal soils.
Casual observations about cotton planting and soil fertility in the U.S. led to the erroneous conclusion that cotton production decreased the fertility of the soil upon which it was planted. The myth of cotton being "hard on the soil" or "a heavy user of soil nutrients" derives from two long-standing and appropriate farming practices: the selection of crops suited for specific soils and the allocation of limited resources to maximize economic return.
During the 1800's the limited distribution capability of agricultural commodities dictated that each farm produce a diverse array of crops to meet the local food needs, to feed the livestock needed to till the soil and to generate income. Thus, farms would plant a mixture of pasture crops, vegetable crops, grain crops and cash crops. Of the latter, cotton fiber was preferred because it had a higher value per pound compared with other crops, and because it could be stored easily until delivered to its point of sale. Presented with an array of soil types and limited fertilizer resources, farmers would plant crops that needed a higher level of soil fertility on the most fertile soil and focus the limited fertilizer resources on these fields. The cotton plant was well known at the time to be tolerant of soil infertility and its seed to be of high value as a fertilizer.i Thus, cotton was planted on the least fertile ground and its nutrient-rich seed, after being separated from the lint at the gin, was applied as a fertilizer to other crops; either directly or after being fed to livestock. Over time this practice depleted the fields of nutrients that were planted just to cotton, which further restricted the planting of higher-fertility demanding crops on these fields. To the casual observer, not familiar with farming practices, it appeared that cotton was "hard on the soil".
Cotton is commonly rotated with other crops.
 Figure 1. The cotton plants pictured above are in a field at the University of Missouri Delta Center where cotton has been grown continuously for over 46 years.
Cotton can be grown continuously without hurting the soil, as illustrated by the vigorously growing plants in Figure 1, where only cotton has been planted in the field for the past 46 years. However, in most environments, it is common practice to rotate cotton with other crops to prevent build up of specific pests, particularly a nearly microscopic one in the soil called nematodes. From Figure 2 it can be seen that there are many crops grown in the same area and rotated with cotton – for example peanuts in the southeast, rice, corn and soybeans in the Mississippi Delta, and vegetable and special crops in California.
 Figure 2. Other crops grown in the Cotton Belt (data for 2006 from the USDA, National Agricultural Statistics Service).
References:
- iTrue, A.C. (1896) The Cotton Plant: Its History, Botany, Chemistry, Culture, Enemies, and Uses. U.S. Department of Agriculture Bulletin No. 53. An excerpt from that bulletin reads: "The small demand made by cotton as compared with other crops upon the plant food of the soil was moreover, well known and the best lands of the Southern plantations – those which were naturally more fertile – were as a rule reserved for corn, wheat and other supply crops. For the same reason, home or stable manures were devoted to the corn and grain lands and practically none applied to cotton. Stable manure and cotton seed were used to considerable extent upon gardens and under grain crops, but only in rare instance with cotton."
|
