Leaf Area and Dry Matter of Four Forage Grasses of Genus Urochloa Subjected to Doses of Aluminum in Nutrient Solution.

The basis for feeding Brazilian cattle is on the grasses. Much of the Brazilian cattle herd is in the region of savannas, which has high acidity and high aluminum (Al) saturation. Therefore studies related to Al tolerance in cultivars of the genus Urochloa is essential to distinguish plants sensitive and tolerant. The aim of this study was to evaluate the leaf area and dry matter of four forage plants: Urochloa brizantha cv. Xaraés, Urochloa brizantha cv. Piata, Urochoa brizantha cv. Marandu and Urochloa decumbens cv. Basilisk subjected to Al rates in the nutrient solution. The concentrations of Al in the solution were 0, 12, 24 and 36 mg L^-1, using the design of randomized complete block design, in a factorial scheme 4 x 4 (four rates of Al x four grasses), with four replications. The experiment was conducted in a greenhouse located at the Center for Nuclear Energy in Agriculture (CENA / USP) in Piracicaba / Sao Paulo / Brazil, in the period from March to May, 2013. The harvest of the material was performed at 35 days after application of the treatments. Analysis of variance for leaf area and dry matter of cultivars was significant (P <0.05) for the interaction cultivars x Al rates. It has been observed a high degree of correlation between leaf area and dry matter as a function of the rates of Al in nutrient solution. The leaf area and dry matter of all cultivars significantly decreased by the presence of Al in nutrient solution.