This study compares yield, nutritive value, and kernel properties of whole plant corn (WPC) harvested before and after a light frost in short growing season areas. Six corn hybrids grown in two years at three locations within Alberta (Canada) were harvested before or after the first frost. Samples of WPC were analyzed for dry matter (DM) content, neutral detergent fiber (NDF) concentration, starch concentration, and 48-h in vitro DM and NDF digestibility (DMD and NDFD, respectively). Cob samples were analyzed for DM, and kernels were analyzed for DM, hardness, particle size distribution, density, and stage of maturity. Delaying harvest to after frost increased DM content of WPC at all locations but exceeded the recommended range (32–38%) in the two warmest locations. Whatever the year and hybrid, DM yield was either not affected or decreased after frost. Postfrost harvest increased starch concentration and modified kernel characteristics only if these were less than expected before frost. Fiber concentration was not affected by harvesting time. Frost had either no impact or increased DMD or NDFD of WPC. We conclude that delaying harvest until after frost in short growing season areas can be beneficial when whole-plant DM content is low before frost.

中文翻译：

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加拿大艾伯塔省霜冻后收割玉米对整株产量，营养价值和籽粒特性的影响

这项研究比较了在短生长期地区霜冻前后收获的全株玉米（WPC）的产量，营养价值和籽粒特性。在第一次霜冻之前或之后，收获了两年内在加拿大艾伯塔省三个地点种植的六个玉米杂交种。分析了WPC样品的干物质（DM）含量，中性洗涤剂纤维（NDF）浓度，淀粉浓度以及48小时体外DM和NDF消化率（分别为DMD和NDFD）。分析玉米芯样品的DM，分析籽粒的DM，硬度，粒度分布，密度和成熟阶段。将收获推迟到霜冻后，所有地方的WPC的DM含量都会增加，但在两个最温暖的地方都超过了建议的范围（32–38％）。不管是哪种年份，霜冻后DM的产量不受影响或降低。霜冻后收获仅在霜冻前少于预期的情况下，才能增加淀粉浓度并改变籽粒特性。纤维浓度不受收获时间的影响。霜冻对WPC没有影响，也没有增加DMD或NDFD。我们得出的结论是，当整个植物中的DM含量在霜冻前很低时，在生长季节短的地区将收获推迟到霜冻后可能是有益的。