Soder Kathy J, Adler Paul R, Dell Curtis J, Williamson Benjamin C
USDA-ARS Pasture Systems and Watershed Management Research Unit, University Park, Pennsylvania, USA.
Department of Animal Science, The Pennsylvania State University, University Park, Pennsylvania, USA.
J Environ Qual. 2025 Sep-Oct;54(5):1258-1270. doi: 10.1002/jeq2.70026. Epub 2025 Apr 25.
Interseeding annual forages into growing corn may be an alternative for both cover and grazing in temperate regions of the United States. A 4-year experiment evaluated the effect of interseeding cereal rye (Secale cereale) into corn for grazing after harvest on corn grain, forage biomass yield and quality, soil health, and estimated spatial biomass yields using vegetation indices (VIs) from multispectral imagery collected from an unmanned aircraft system platform. Corn was planted (79,074 plants ha) each spring on two 4.8-ha sites in central Pennsylvania. Cereal rye was interseeded (135 kg ha) into corn at the V4-V6 stage. Corn was harvested as grain in November, and each site was subdivided and randomly assigned to grazed or non-grazed treatments. Biomass yield and quality, soil samples, and estimates of biomass yield using VIs from multispectral imagery monitoring occurred in fall and spring. Results indicated that cereal rye plus corn stover provided enough forage for an additional 105-130 animal unit days ha with minimal impact on soil health indicators. Vegetative indices varied in the ability to predict biomass yield; all VIs except normalized difference red edge saturated at ∼2 Mg ha. Spring growth of cereal rye was much less dependable than fall. Corn grain yields did not decrease (averaging 9.9 tonnes of dry matter ha) as a result of grazing or due to continuous corn planting except in 2019 (dry year) when corn grain yields were reduced by 35%-40%. Interseeding cereal rye into corn that is harvested as grain can be a viable method to establish a cover crop to extend the grazing season without impairing cash crop yield.
在美国温带地区，将一年生牧草套种到生长中的玉米地里，或许是一种既能提供覆盖又能用于放牧的选择。一项为期4年的试验评估了在玉米收获后套种黑麦（Secale cereale）用于放牧对玉米籽粒、牧草生物量产量和质量、土壤健康的影响，并利用从无人机系统平台收集的多光谱图像中的植被指数（VIs）估算了空间生物量产量。每年春天，在宾夕法尼亚州中部的两个4.8公顷的地块上种植玉米（每公顷种植79,074株）。在V4-V6阶段将黑麦（每公顷135千克）套种到玉米地里。11月收获玉米籽粒，每个地块再细分并随机分配到放牧或不放牧处理组。在秋季和春季进行生物量产量和质量测定、采集土壤样本，并利用多光谱图像监测的植被指数估算生物量产量。结果表明，黑麦加玉米秸秆可为每公顷额外提供105-130个动物单位日的牧草，且对土壤健康指标的影响最小。植被指数在预测生物量产量的能力方面存在差异；除归一化差值红边指数外，所有植被指数在生物量约为2 Mg/公顷时饱和。春季黑麦的生长远不如秋季可靠。除2019年（干旱年份）玉米籽粒产量下降35%-40%外，放牧或连续种植玉米并未导致玉米籽粒产量下降（平均每公顷干物质产量为9.9吨）。将黑麦套种到收获籽粒的玉米地里，可能是一种可行的方法，既能建立覆盖作物以延长放牧季节，又不影响经济作物产量。
