在最适的时期有足够成苗数是影响冬小麦和冬大麦籽粒产量潜力的重要因素。太平洋西北部休闲轮作区,冬种作物栽培期间有足够数量发育良好的壮苗,还具有减少水土流失的作用。雨量较少的地区长期以来推广在九月中至十月初播种。播种过早的,禾谷类作物所吸收的水分常超过限量,对冻害更敏感,而且常常容易发生病害。秋季接受降雨的可能性随时间而增加,该地区有许多出壤即使下一点小雨,土表也容易结硬壳。硬壳土体密度大,会妨碍出茁,因此,早播具有减少出苗前受硬壳危害的优点。 Sufficient number of seedling in the optimum period is an important factor affecting the grain yield potential of winter wheat and winter barley. There are ample number of well-developed strong seedlings during the cultivation of winter crops during the winter crop rotation in the Pacific Northwest, as well as reducing the loss of soil and water. The areas with less rainfall have been sown for a long time between mid-September and early October. Sowing premature, cereal crops often exceed the amount of moisture absorbed, more susceptible to frost damage, and often prone to disease. The chances of autumn receiving rainfall have increased over time, and there are many out-of-the-earth rains in the area that can easily crust hard surfaces. Hard shell soil density, will hinder the Zhuo, therefore, early sowing has the advantage of reducing pre-emergence by the hard shell hazards.