Drought-Related Characteristics of Important Cereal Crops - Monitoring and Predicting Agricultural Drought: A Global Study - page 16

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Table 2.1 Global maize production and area harvested

Country Area (%) Production (%)

United States 20.3 39.6

China 17.0 18.3

Brazil 9.0 6.9

Mexico 5.3 3.1

Argentina 2.0 2.5

France 1.4 2.7

Others 45.0 26.9

World total 138 Mha 604 Tg

Source: FAO (2001).

[16],

matric potential at 25 cm depth reached 0.1 MPa produced the greatest

irrigation WUE in North Dakota, United States. Because the WUE depends
on the water-holding capacity of the rooted soil layer, irrigation schedules
must be optimized for each location.
Optimum WUE also depends on crop nutrient status. Sylvia et al. (1993)
also found that they could improve maize grain yield at an average of
0.8 Mg/ha across a range of irrigation levels though inoculation with my-
corhizae ( Glomus etunicatum Becker and Gerdemann), a soil fungus that
functions to increase the absorptive area of roots.

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PgEn

M ycotoxins

[16],

For maize, it is especially important to recognize that drought reduces crop
quality as well as productivity. Under drought, fungi often attack maize
ears and may produce mycotoxins, especially aflatoxins and fumonisins,
which are among the most carcinogenic natural substances known. My-
cotoxins have serious health implications for humans and livestock. They
may cause liver cancer, thyroid cancer, reduced immune system function,
slowed growth of livestock, and exacerbation of other illnesses (Galvano
et al., 2002). Wherever and whenever maize crops are exposed to drought
during grain filling, a special effort should be made to prevent consumption
of these mycotoxins.

C rop Management

In western Kansas, United States, farmers grow rain-fed sorghum but gen-
erally do not grow maize because they believe it is insufficiently drought
and heat tolerant for rain-fed production. In a five-year field experiment,
Norwood and Currie (1997) found that no-till cultivation increased maize
yields by 28% and net returns by 69% compared with conventional tillage.
In contrast, no-till cultivation increased sorghum yields by only 11% and
did not increase net return. Moreover, no-till maize yielded 28% more
grain with 169% greater net return than no-till sorghum over the course