灌漑・排水システム工学

Complementary Irrigation in a Maize Silage Double Crop using the BAHICU Software: A Case Study in Northern Buenos Aires, Argentina

Abstract

Lopresti MF and Bertin OD

Northern Buenos Aires (Argentina) is a rain fed agricultural region. Complementary irrigation, which is mainly used in maize crop, requires the contemplation of strategies that minimize the soil solidification risk. The first alternative to mitigate the limited water quality is to perform an irrigation schedule by using the water balance methodology. The BAHICU software, developed in the study region, is a soil water balance model for agricultural systems under irrigation. The objective of the present study was to evaluate the forage production of irrigated and rain fed double crop of silage maize, using the BAHICU software as a tool to make a more efficient water use and to attenuate the adverse effect of the sodium present in the irrigation water. A field experiment was conducted on a clay soil with a sequence of two maizes during the 2015-2016 growing season: short season maize (maize 1) and late sown maize (maize 2). There were two preceding winter crops: ryegrass and oat. Plant height, dry matter (DM) percentage and DM yield were measured. Crop evapotranspiration (ETc) of irrigated and rain fed treatments was obtained from the BAHICU software. Irrigation was applied using a sprinkler system. Irrigation influenced only the yield of maize 2. Water use efficiency (WUE) did not vary with irrigation incorporation. Maize 2 presented higher forage production and WUE than maize 1. An R2 value of 0.82 was found after relating DM yield with maize ETc. The preceding winter crops only influenced the yield of the maize 1. The DM yield was linked to plant height. The irrigated maize 2 was the only treatment that presented an optimal DM percentage for silage conservation. Using the BAHICU software allowed comparing the WUE of the maizes analyzed. Irrigation influenced crop yield but not WUE.