Impact of different strategies of supplementary irrigation in the wheat yield

MARANO, R.; ALBRECHT, G.; CARNEVALE, I.; MICHELOUD, H.; IMHOFF, S.

Montevideo

Congreso; 19th ISTRO Conference; 2012

ISTRO

The objective of this research was to evaluate the response of wheat production to different strategies of supplementary irrigation. The experiment was carried with 3 treatments: full irrigation (FI), partial irrigation (PI) and no irrigation (NI). Three plots of 20 m2 were randomly delimited in each treatment. Actual evapotranspiration (ETa), net irrigation depth (IDn) and reference crop evapotranspiration (ETo) were determined. Yields (Y) and water use efficiency (WUE) were measured, as well as crop coefficients (Kc) for FI, water stress coefficients on base of soil (Ks) for PI and NI, and yield response factor (Ky) for FI and PI. In the first year 160 and 109 mm of water were applied in FI and PI. ETa was 347, 305 and 164 mm for FI, PI and NI. ETo was 367 mm. The Kc values were 0.2, 1.53 and 1.0. Ks values were 0.47 and 0.96 for NI and PI, while Ky was 1.37 and 1.24 for PI and FI. There were no significant differences in Y between PI and FI (3400 kg ha-1), while the NI yield was 1200 kg ha-1. The larger WUE value was observed in PI (1.08 kg m-3). The second year was wet, requiring only 63 mm of IDn. ETa was 524, 495 and 402 mm for FI, PI and NI, with 511 mm of ETo. Kc was similar to the previous year. Ks values were higher. Ky was not sensitive to detect water stress. FI and PI yields did not differ (8100 kg ha-1 average), but NI Y was significantly smaller (6920 kg ha-1). The PI strategy had economized water without impacting on the wheat yields. On the other hand, when rainfall is scarce, the FI strategy will be the best option to get good yields.