The effect of off-season irrigation practices on crop growth

investigate the effects of off-season irrigation practices on crop growth. Crops used in the study were alfalfa and spring wheat. Two spring wheat harvests and five alfalfa cuttings were removed from each plot for analysis. For alfalfa, annual irrigation treatments varied from a single fall irrigation to four water applications. Similarly, timing of irrigation in spring wheat treatments varied from once per year to numerous applications according to stage of growth. An irrigation was defined as the filling of the soil profile to field capacity. In addition to the climatological data recorded at the Bozeman 6W meteorological station, soil moisture throughout the active root zone and soil temperatures at the 5 cm and 20 cm depths were also monitored. Yields among certain of the spring wheat treatments were found to differ significantly during the 1978 season but the yield data could not be related to treatment since the timing of the irrigations were in question. Of the five alfalfa harvests, only the second cutting in 1979 had yield differences with statistical significance at the 95 percent level of confidence. The single Fall irrigation treatment resulted in yields that were considerably less than the treatments with the more frequent water applications only during this summed: 1979 period indicating that a single annual water application might be adequate during certain years for production of alfalfa on the deep soils of th