Leaf Water Potential of the Purple Elephant Grass, Pennisetum purpureum Schumach. (poaceae) and it’s Relationship with Soil Moisture

摘要

Objectives: To investigate how the time of day affects the water potential values of the purple elephant grass ( Pennisetum purpureum ) in areas with and without irrigation during the dry season and the relation with soil moisture, in order to establish a good performance of the crop. Method: Water potential was measured with the Scholander pressure chamber and humidity was measured with a Moisture Soil Kit. Four demonstration plots of 3 m × 3 m (three with irrigation and one without irrigation) were select and the determination was made at: 08:00, 13:00 and 17:00, for 10 weeks two days a week. Findings: The crop under irrigation maintained values of water potential between 0.02 to 0.05 MPa, and crop without irrigation between 0.02 and 0.25 MPa. Additionally, a higher yield was obtained for the irrigated crop of 22 t/ha/year in dry matter. The purple elephant grass maintains a good yield with humidity between 20% and 30% and water potential between 0.03 and 0.05 MPa. Novelty /Improvement: Obtaining the equation (Y = 0.493 * X - 0.775 ) that relates soil moisture and leaf water potential of purple elephant grass Pennisetum purpureum Schumach. (Poaceae), which can be used to find the water potential (Y) in a soil with a sandy clay loam texture.