Chinese Maize Production – The Critical Need For Technology.

The mean Chinese maize (Zea mays L.) yield is about half of that of the US (5.3  vs  approximately 10 t ha^-1).  Since 2000 increased grain production in China has come from an increase in the areas devoted to maize production rather than an increase in production per unit area of land.  In the US, yield increases were only obtained when using responsive hybrids with tolerance to the stress of high seeding rates.  Without the changes in management and equipment the advantage of the newer hybrids disappeared.  In a set of three year studies in Jilin Province, the yield response of 15 currently available Chinese hybrids, seeding rates from 50,000 to 90,000 seed ha^-1,  N fertilization rates from 85 to 250 kg ha^-1, and planters (Chinese and John Deere MaxEmerge XP) was investigated.  The Chinese hybrids were not responsive to seeding rate and showed only a 1.5 t ha^-1 difference between the lowest and highest N rate.  The US planter did produce, on average, about 0.7 t ha^-1 more grain than did the Chinese planter due to a decreased variance of emerged plant spacing for the US planter (83 cm² vs 128.9 cm²). In the US yields have increased by exploiting the complimentary relationship between genetics, equipment, and crop and soil husbandry.  The yield increases that China desires and needs will only be obtained when this complimentary condition is exploited there as well.