The total area of land dedicated to cotton growing has not changed significantly for around 80 years, but in that time output has tripled. This hike in productivity is widely attributed to the application to the cotton crop of very large quantities of fertilizers and pesticides, which in turn have caused a range of well-documented environmental impacts including: reduced soil fertility; loss of biodiversity; water pollution; pesticide-related problems.
Cotton growing, health problems
Including resistance; and severe health problems relating to exposure to acutely toxic pesticides. Pesticides (a generic term incorporating insecticides, herbicides and fungicides) account for more than 50 per cent of the total cost of cotton production in most of the world. In cotton production, the use of insecticides dominates, with pyrethoids and organophosphates being most widely used. The World Health Organization has classified these as ‘moderately hazardous’.
However, some organophosphates, especially those used in developing countries, are classified as ‘highly hazardous’, are generally acutely toxic nerve poisons and can contaminate groundwater. Large amounts of synthetic fertilizers (often based on nitrogen compounds) are also applied to the crop and can result in nitrate contamination to water, with the effect of accelerating the growth of aquatic plants and algae, and subsequent deoxygenation of water into a state in which it cannot support animal life.
The cotton crop is sometimes highly irrigated and cotton agriculture has been associated with adverse changes in water balance, the most infamous case being the ‘drying up’ of the Aral Sea after water was diverted from two feeding rivers to irrigate cotton plants.8 The quantities of water needed to irrigate the cotton crop vary according to climate from as much as 29,000 litres per kg of cotton in Sudan to 7000 litres per kg in Israel.
However, it should be noted that 50 per cent of land under cotton cultivation is not irrigated but rain-fed, and because water cannot be ‘used up’ (it is circulated in a natural cycle), problems associated with high levels of water use are linked more to access to water (through wells and infrastructure) and to contamination (by fertilizers and pesticides) that makes it unfit for use for other purposes.
Organic Cotton, Grown in the USA
In Central Asia, perhaps the area of most inefficiently irrigated cotton, 60 percent of the water is lost before reaching the fields because of poor infrastructure. Furthermore, irrigation techniques in these areas are extremely inefficient, resulting in huge additional waste of water.
Other inputs in cotton cultivation include between 0.3 and 1kg of oil per kg of cotton fibre (depending on the extent to which cotton growing is mechanized) to run the farm machinery and to fuel the planes for aerial spraying.10 If cotton is machine picked it is routinely sprayed with defoliants prior to harvesting to speed up the process, and it tends to contain considerably more impurities (seeds, dirt and plant residues) than hand-picked cotton.
Alternatives: organically grown cotton; low-chemical cotton; hand-picked cotton; rain-fed cotton; drip-irrigated cotton; substitute fibres, such as hemp or flax.