creased from 7.3 to 55.9 kg/ha per year (Goskonstat, 1975) but there was a significant temporary decrease in fertilizer use in the CEE and CIS countries in the late 1980s due to the collapse of the former Soviet Union. While P use leveled off in North America around 1980, N use is still increas­ing, though at a slower rate than pre-1980 (Figures 2-11 and 2-12). Fertilizer use in the intensive cropping systems of the NAE is partly responsible for the considerable gains in agricultural productivity in NAE since the 1950s. Until recently, fertilizer has been relatively cheap for farmers and the profits from yield increases achieved far exceeded the costs of the additional fertilizers.

2.4.3.4 Pesticide usage in NAE cropping systems Synthetic chemical pesticides were developed and intro­duced after 1945 and have since become the major form of pest management in agriculture and stored products in NAE. The term pesticide refers to herbicides, insecticides and fungicides, as well as products that control rodents, nematodes and other pests and treat or preserve timber. Over 1000 chemicals are marketed worldwide, sold in tens of thousands of formulations (Tomlin, 2006).
     A program for registration of pesticides was initiated in 1947 by the US Department of Agriculture and is cur­rently under the authority of the US Environment Protection Agency (Pierzynski et al., 2000). All NAE countries now have stringent requirements for the registration of pesti­cides, which authorize specific formulations for each crop and require evidence of tests on non-target organisms, fate and transport of pesticides. Data requirements have pro-

gressively increased to address environmental and health concerns. The organochlorine pesticides which represented the first generation of insecticides were bioaccumulative and environmentally persistent. This led to a series of bans and withdrawals in NAE and worldwide. In 1960, chlorinated pesticides had represented about 75% of insecticide use in the US, but by 1997 these were less than 3% (see Aspelin, 2003). Nine of these insecticides are now scheduled to be withdrawn from production and use under the Stockholm Convention on Persistent Organic Pollutants. Since 1992, discussions have taken place to globally harmonize the clas­sification and labeling requirements for pesticides world­wide (OECD, 2004).
     Synthetic chemical pesticides did not become available until after 1945; massive increases in use were recorded in NAE from 1950 onwards. Trends in use by volume in the USA (Figure 2-13) are also similar to Western Europe, showing a peak in the 1980s. Measurement by volume use is a limited indicator of pesticide use and change, as it amal­gamates information on products used in undiluted form, reflects neither their toxicity to different organisms nor their persistence in the environment and masks the fact that newer pesticides are developed to be more active at lower rates of application. In 1997 approximately 350,000 tonnes (USA), 32,000 tonnes (UK) and 100,000 tonnes (France) of pesti­cides were used on agricultural crops (FAOSTAT, 2006).
     Detailed changes at country level are difficult to access, but an example from UK national pesticide survey data demonstrates large increases in land area treated with fun­gicides and herbicides between 1974 and 2002. Increases