Rotating wheat (Triticum spp.) with fallow is a popular practice in the North American Great Plains, in spite of environmental degradation and economic inefficiencies. Two-year crop sequences were established in four fields in central Montana to determine if grain yield could be maintained when wheat followed warm-season annual crops compared with fallow in shallow (soil depth ≤650 mm) dryland soils. More than 15 warm-season species along with three crop mixtures were managed as cover, forage, and grain or seed crops in the 1st year. Differences were not detected in volumetric soil water content (VWC) following fallow and warm-season crops (P > .8). Wheat yield following fallow averaged 2.1 Mg ha^–1 and was comparable following warm-season broadleaf crops and grass-broadleaf crop mixtures (2.0 Mg ha^–1, P > .50), while trending downward slightly following grasses (1.9 Mg ha^–1, P = .08). Previous crop management (cover, forage, and grain or seed crop) did not affect subsequent wheat yield (P = .98), but did affect wheat grain protein (P < .01). Wheat grain protein concentration was higher following fallow (124 g kg^–1) than warm-season grass and broadleaf crops, as well as mixtures (116 g kg^–1), but was below the 132 g kg^–1 threshold indicating N deficiency, regardless of previous-year treatment. These results indicate that grain yield of wheat can be maintained following warm-season annual crops compared with fallow in central Montana and similar semi-arid environments with shallow soils, though soil N supplementation is needed to optimize grain yield and quality.

中文翻译：

---

在旱地小麦系统中用暖季一年生作物代替休耕

尽管环境退化和经济效率低下，轮作小麦（小麦属）休耕是北美大平原的一种流行做法。在蒙大拿州中部的四个田地中建立了两年作物序列，以确定当小麦在暖季一年生作物之后与浅层（土壤深度≤650 毫米）旱地土壤休耕时是否可以保持粮食产量。在第一年，超过 15 种暖季物种以及三种作物混合物作为覆盖物、饲料、谷物或种子作物进行管理。休耕和暖季作物后土壤体积含水量 (VWC) 未检测到差异 ( P  > .8)。休耕后小麦产量平均为 2.1 Mg ha ^–1并且在暖季阔叶作物和草-阔叶作物混合物（2.0 Mg ha ^–1，P  > .50）之后具有可比性，而随着禾本科植物（1.9 Mg ha ^–1，P  = .08）呈下降趋势。先前的作物管理（覆盖物、草料和谷物或种子作物）不影响随后的小麦产量 ( P  = .98)，但确实影响小麦籽粒蛋白质 ( P  < .01)。休耕后的小麦籽粒蛋白质浓度 (124 g kg ^–1 ) 高于暖季禾本科和阔叶作物以及混合作物 (116 g kg ^–1 )，但低于 132 g kg ^–1指示 N 缺乏的阈值，无论前一年的处理如何。这些结果表明，与蒙大拿州中部和类似的浅土壤半干旱环境的休耕相比，暖季一年生作物可以保持小麦的粮食产量，尽管需要补充土壤氮来优化粮食产量和质量。