Fertility, declining

Nonaka K, Miura T, Peter (1994) Recent fertility decline in Dariusleut Hutterites an extension of Eaton and Mayer s Hutterite fertility study. Hum Biol, 66 411-420. 

Heerink, N. (2005) Soil fertility decline and economic policy reform in Sub-Saharan Africa.- Land Use Policy 22, 67-74. 

Superphosphate a fertilizer declining strongly in importance (PiOj-contcnt only 20%)... 

Pesticides have been shown to impact every one of the six processes just listed. Since pesticide residues are ubiquitous in the human environment and food supply worldwide (see Chapter 10), fertility declines should not be surprising. An excellent review of the subject is contained in a recent article by Bretveld et alJ3l... 

Loss of soil fertility, declining crop yields ... 

Fertility declines in East Asia since 1950 have been dramatic, dropping to about replacement levels or below in Japan, Taiwan, Korea, and China 93 In Thailand, fertility dropped from 6 children per woman in the 1960s, to 3.7 in 1980, and to the replacement level of 2.1 in 1991.94 Adult women in Thailand have a literacy rate of 90% compared with 96% for men. 

Table 7. Area ajfected by soil fertility decline in South Asia (000 ha).

Country Degree of soil fertility decline. Total Total as per cent of agr, land... 

Soil erosion results in a net removal of nutrients from the remaining soil. In addition, the continued use of compound, inorganic fertilizers in most countries is causing marked deficiencies of many major, secondary and micro-nutrients. In a number of cases, imbalanced use of fertilizers dominated by nitrogen has caused multiple nutrient deficiencies. For example, in Bangladesh, more than 50% of the total area has suffered from soil fertility decline (Table 7). 

Wickrama, K. A. S., and F. O. Lorenz. Women s statns, fertility decline, and women s health in developing countries Direct and indirect influences of social status on health. Rural Sociology 67 255-277, 2002. 

Although this would require steep fertility declines in a number of populous countries with high fertilities—most notably in Nigeria and Pakistan (whose current fertilities are 5.9 and 5.0, respectively)—such reductions would not be unprecedented. China cut its fertility from about six in the mid-1960s to less than two by the mid-1990s, and a number of smaller Asian countries accomplished their demographic... 

Thai fertility dropped from 6.4 in the late 1950s to 1.9 by 1995, and South Korean fertility declined from 6.3 to 1.7 during the same period see United Nations (28), annex I,... 

The wodd s largest sulfur iaveatories are stiH ia Canada. By the end of 1994, after significant vattiag, stocks iacreased by approximately 2.2 x 10 to 7.8 X 10 t. The United States, which had 4.2 million metric tons of sulfur inventories in 1982, reduced sulfur inventories to the lowest levels in a decade during 1992, a record year for phosphate fertilizer exports. This changed during 1993—1994, when phosphate fertilizer production eased and sulfur stocks increased to 1.1 million metric tons. Sulfur inventories in Poland and West Asia have also declined slightly (33). 

Historically, consumption of sulfuric acid has been a good measure of a country s degree of iadustrialization and also a good iadicator of general busiaess conditions. This is far less vaUd ia the 1990s, because of the heavy sulfuric acid usage by the phosphate fertilizer iadustry. Of total U.S. sulfuric acid consumption ia 1994 of 42.5 x 10 metric tons, over 70% went iato phosphate fertilizers as compared to 45% ia 1970 and 64% ia 1980 (144). Uses other than fertilizer have grown only slowly or declined. This trend is expected to continue. Production and consumption trends ia the United States are shown ia Tables 9 and 10. 

Controversy will continue to persist over allegations that sperm counts are declining. Prospective studies on semen quality in fertile men involving centres in... 

Europe, the USA and Japan are under way. In these studies, semen analysis methodology and subject selection criteria have been standardised to address whether there are region-specific differences in semen quality. These data can then be used as a reference point for any studies on future decline in sperm counts. More importantly, it still remains to be demonstrated whether the reported decrease in semen quality is sufficient to compromise fertility. 

Acetylene and ethylene compete as a chemical raw material. Ethylene is generally more economical, resulting in declining use of acetylene as a raw material. Calcium carbide, a raw material for acetylene has other uses. Treated with nitrogen, it gives calcium cyanamide, valuable as a fertilizer and weed killer, and a raw material for the production of melamine, used ir ng some modern plastics. 

A useful device to have installed in a stirred autoclave is a liquid sampling tube by which liquid samples are withdrawn under pressure through a filter attached to the lower end of the tube. This device is especially useful for analysis of reaction progress and supplements information obtained from pressure-drop determinations. It is much easier to improve a less than satisfactory yield, if it can be determined what is going wrong and when. For academically orientated persons, a study of the rise and decline of various reaction products, as a function of reaction parameters and catalyst, can be a fertile source of useful publications. 

In some animals, consumption of a phytoestrogen-rich diet can cause temporary infertility and reproductive system disorders (Irvine, 1999). In humans, lower testosterone levels and a decline in human semen quality over the past century have been luiked to increased exposure to environmental endocrine disrupters (EDCs) (Sharpe and Skakkebaek, 1993). Furthermore, cases of sexual impotence have been reported in males exposed to synthetic estrogens in the pharmaceutical industry (Mattison et al., 1990). If this might be the case, the fetal-prepubertal period and Sertoli cell development would be of critical importance (Sharpe and Skakkebaek, 1993). However, an adverse effect of phytoestrogens on male fertility has yet to be proven. Recent work (Mitchell et al., 2001) addressing this point led to the conclusion that up to 40 mg/day of isoflavones over a two-month period had no effects on gonadotrophin and... 

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