Resumen

SANTAMARIA CESAR, Jesús; RETA SANCHEZ, David G.; FAZ CONTRERAS, Rodolfo  y  ORONA CASTILLO, Ignacio. Potential Yield Reduction of Forage Maize under Irrigation Schedules with Three and Four Irrigations. Terra Latinoam [online]. 2008, vol.26, n.3, pp.235-241. ISSN 2395-8030.

The objective of this study was to determine and to compare the potential yield reduction (PYR) of forage maize under irrigation schedules with three and four postplanting irrigations considering climatic and soil available water (AW) conditions in the Irrigation District 017, Comarca Lagunera, Mexico. Values of PYR estimated using the CropWat model were compared for two sowing dates and two soils with different AW (120 and 150 mm m^-1). Kc coefficients for maize obtained in experiments established in the Comarca Lagunera in 1997, 1998, and 2000 were used in this study. Climatic data over 31 years (1975-2005) were used. Application of a fourth irrigation in soils with 120 mm m^-1 of AW reduces PYR by 15%, which is equal to a dry matter yield increase of 4.6 Mg ha^-1; whereas in soils with 150 mm m^-1 a fourth irrigation reduces PYR by 9% and increases dry matter yield by 2.7 Mg ha^-1 due to better soil moisture conditions during the grain fill phase. In soils with 120 mm m^-1 of AW four irrigations are necessary to reach dry matter yields of 17.7 Mg ha^-1, with a probability of up to 0.793. In soils with 150 mm m^-1 of AW the irrigation schedule with three irrigations dry matter yields of 18.8 Mg ha^-1 are obtained, and with a fourth irrigation dry matter yields up to 21.2 Mg ha^-1 can be achieved; this is the best option for forage maize production in Irrigation District 017. For all conditions evaluated in this study, the yield level equal to or higher than 80% of maximum experimental yield (23.92 Mg ha^-1) has a probability below 0.168.

Palabras llave : Zea mays L.; CropWat model; irrigation schedules; soil available water.