Agricultural History Review, Volume 51 Part 1 (2003), p. 132

Lindert suggests that the cultivation of cropland soils in China and Indonesia has not been decreasing soil quality, except for reducing some nitrogen and soil organic matter. His arguments rest generally on the facts that the total number of hectares under cultivation in China and Indonesia have not declined over time and that phosphorus and potassium nutrients have increased in some soils. Several of the tables lacked sources and this was disappointing.

Although the net area under cultivation may remain the same in China and Indonesia, this conceals changes in the land used for crops from one year to the next. In China, more and more forest land and grassland have been cleared and converted into cropland in recent decades. Soil scientists have reported that in northeast China soil erosion is serious on about 13.3 million ha. Fu Dexin and Tang Defu estimate soil erosion rates in the rolling land area of Songhuajiang-Nenjiang plain, with 2 million ha of cropland, at 50 to 70 t/ha/yr. In this region of rich soils, farmed for only sixty to seventy years, 60 to 70 cm of thick black soil has been reduced to 20 to 30 cm. Further evidence of soil erosion in China is the soil deposited on Hawaii during Chinese spring cultivations each year (see Parrington et al. Science 264 (1983), pp.195–7). In contrast to dryland crop production in China and Indonesia, the production of paddy rice suffers little or no soil erosion because the land is flat and covered by water for most of the time. In these circumstances, wind and rainfall energy have little or no effect on the soil.

Lindert’s view that there has been little or no degradation of cropland soil in China is therefore at odds with the assessments of many soil scientists. Wen and Pimentel (in Tao et al. (eds), Agriculture in China (1998)) estimate that China loses about 5.5 billion tonnes of soil each year, while Zhang and others (Land Degradation and Development 8 (1997) pp.1–16) report that the Yellow River transports approximately two billion tonnes of soil per year to the sea. Loss of vegetative cover is widespread in China, Indonesia, and other developing countries. With high population densities and shortages of forests to provide fuelwood, people are turning more to crop residues for cooking and heating. Wen (in Pimentel (ed.), Soil erosion and conservation (1993)) estimates that about sixty per cent of the crop residues in China are stripped from the land and burned for fuel. In areas where fuel wood and biomass are scarce, such as northwestern China, even the roots of grasses and shrubs are collected and burned, thus intensifying soil erosion.

Lindert reports that nitrogen and soil organic matter have declined in some soils in China and Indonesia but that total phosphorus and potassium generally increased from 1950 to about 1985. In both countries, fertilizer use has increased significantly since the 1950s in an effort to feed rapidly growing populations. In China, cereal grain production doubled between 1965 and 1983. To achieve this increase in crop yields, fertilizer inputs increased 7.5 fold, insecticide use increased two fold, diesel fuel use six fold, and electricity inputs eleven fold. In China, yields per hectare for several crops are now higher than in the United States, but so too are inputs of fertilizer, pesticides, and irrigation water.

The loss of soil organic matter and the loss of soil nutrients due to soil erosion in China, Indonesia, and other nations is serious. Soil loss and degradation are of concern to everyone because more than 99.7 per cent of world food comes from the land and less than 0.3 per cent from the oceans and other aquatic ecosystems. The loss of soil and land degradation due to erosion are having a negative impact on world food supplies. In 2000, the World Health Organization reported that more than three billion people are malnourished worldwide. This is the largest number of malnourished people ever in history.

Lindert is to be complimented for examining the issue of soil loss and degradation in China and Indonesia, even though his conclusions appear to differ from those of soil scientists in China, Indonesia, and elsewhere. Shifting ground is well written and carefully illustrated. Economists, agronomists, soil scientists, biologists, engineers, and environmentalists should find the book interesting reading.