Maize agricultural production

Starch is the other carbohydrate-based feedstock. Approximately 10 Mt is produced annually from corn (maize), wheat and potato, out of a total agricultural production of 1.6 Gt a-1 carbohydrate equivalents. A minor fraction of starch is amylose, a linear a 1 ->4 polymer of glucose (Fig. 8.2b). The native structure of amylose is helical loose random coils are formed upon dissolution in water. The branched glucose polymer amylopectin is the major (approximately 75%) component of starch. 

Predictions of changes in productivity are difficult in part because a major cause of probable climate change is increasing atmospheric carbon dioxide, which is also the raw material for photosynthesis. Enriching the atmosphere with CO2 could potentially speed rates of photosynthesis and, thereby, increase agricultural production. Indeed, laboratory experiments in which CO2 concentrations were increased from 300 to 600 ppm, increased photosynthetic rates by 20% in maize and 60% in wheat (Akita and Moss, 1973). Laboratory experiments also show that enrichment with CO2 increases the growth of root shoots and increases tire efficiency of water use. 

On the other hand, agricultural wastes can be alternatively used as substrates for edible biomass production. Cotton plant stalks [8], maize residues [9], olive milling wastewater [10] have been tested for cultivation of Pleurotus sp. fruiting body. 

Land use in the Ebro River basin has been traditionally based on agricultural crops, such as vineyards, orchards, and maize. Up to 783,948 Ha are dedicated to agriculture, and mainly in the mid and lower Ebro sections, are irrigated. Nowadays, industry is a relevant activity at the most important cities (e.g., Zaragoza, Pamplona). Hydroelectric energy production uses about 8,297 m3/s in 340 hydroelectric plants at the Ebro River basin. Water of the Ebro River is also used for cooling nuclear and thermic plants. Urban water demand is 5% of that used for agriculture. 

Despite the advantages mentioned above, there are important limitations. In fact, agricultural cultivation devoted to ethanol production requires large areas and consumes significant water resources, as in the case of sugar cane. It has been indicated that overcropping of the soil can be a problem in some cases. For other cultivations, such as maize, a possible competition between food and energy was indicated. 

Blackie, M. J. (1994) Maize productivity for the 21st century the African challenge.- Outlook on Agriculture 23, 189-196. 

Veluti, A., Sanchis, V., Ramos, A.J. and Marin, S. (2004) Effect of essential oils of cinnamon, clove, lemongrass, oregano and palmarosa on growth and fumonisin B1 production by Fusarium verticillioides in maize. Journal of the Science of Food and Agriculture 84(10), 1141-1146. 

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