Zea mays and Sorghum halepense water competition and their impact on leaf gas exchange

Abstract

Acciaresi, H., Zuluaga, M., Yanniccari, M., Guiamet, J. (2012). Zea mays and Sorghum halepense water competition and their impact on leaf gas exchange. Ecosistemas 21(3):103-109. Doi.: 10.6778/ECOS.2012.21-3.15

In an environment with water restrictions, the high stability of the production has been linked to the water conservation ability of the crops. However, under water competition, different weed species show inefficient water use. In order to determine the strategy of water consumption of Zea mays and Sorghum halepense under two soil water availability conditions, soil (s) and leaf water potential (f) trends, relative water content (RWC) and leaf gas exchange were measured during the critical period of crop competition in pot experiments. In addition, efficiency of water use, relative yield total (RYT) and aggressivity index (AGR) of both components were calculated. S.halepense shown a continuous absorption of water, reaching a lower f than those observed in Z.mays hybrids. S.halepense maintained the RWC above 90%, reached 70% only in competition with low water availability. In Z.mays, the RWC declined to values of 70% for both water levels studied. S.halepense showed an active leaf gas exchange. Z.mays hybrids have had a less competitive ability that S.halepense for both competition levels due to the conservative water strategy of the crop. Water use by the weed could be a cause of the increased aggressiveness of S.halepense under study conditions.