Abstract:

[Objective] This study aimed to explore the responses of forage oat yields to precipitation changes in varied growth periods under different precipitation year patterns, and to provide references for drought-resistant and high-efficient production of forage oats.[Method] A crop growth mechanism model of Agricultural Production Systems Simulator （APSIM） was employed. The historical meteorological data from the year of 1980 to 2009 of Youyu County, Shuozhou City, Shanxi Province was taken as the baseline scenario. The growth periods of forage oats were divided into 4 stages, including stage 1 being from sowing to jointing, stage 2 being from jointing to heading, stage 3 being from heading to grain filling, and stage 4 being from grain filling to harvesting. A total of 12 new climate scenarios were established and simulated based on the typical climate conditions （drought, normal and wet) to reveal the influences of precipitation changes on forage oat yields. [Result] For the drought scenario （DS）, the yields and water use efficiency （WUE） were decreased by 38.0%-60.9% and 31.8%-16.9% （P<0.01） respectively compared with the baseline scenario, and the reduction range of the indicators in the stage of heading to grain filling was the lowest when the historical data were used. For the normal scenario （NS）, the changing range of the yields and WUE were -3.4%-20.0% and 0-10.0% respectively compared with the baseline scenario, and the indicators altered significantly （P<0.05） in the stages of jointing to heading and grain filling to harvesting when the historical data were used. For the wet scenario （WS）, the yields and WUE showed significant （P<0.01） elevations compared with the baseline scenario with increasing rate of 33.3%-60.5% and 6.8%-14.8%, respectively, and the precipitation changes in the stage of sowing to jointing had relatively markedly effects on the indicators （R²=0.377 7, P<0.01）. [Conclusion] The forage oat yields and WUE present insignificant sensitivity to the precipitation changes in the stage of grain filling to harvesting under the precipitation year patterns of drought, normal and wet. Under the precipitation year patterns of drought and normal, the yields are more sensitive to drought stress in the stage of heading to grain filling, while WUE is more sensitive to drought stress in the stages of jointing to heading and heading to grain filling. Under the precipitation year pattern of wet, the most sensitive period of the yields to drought stress is the stage of sowing to jointing. Under the limited irrigation conditions, the irrigation should be concentrated in the stage of heading to grain filling in which WUE demonstrates the most sensitivity to the precipitation changes.

Key words: crop model, precipitation year pattern, forage oats, yields；, water use efficiency