Optimizing nitrogen fertilization and harvest management in crabgrass hayfields
The paper “Management strategies to improve forage accumulation and nutritive value in crabgrass hayfields“, published in The Journal of Agricultural Science, has been chosen as the latest Editorial Highlight and is freely available to download for one month.
The use of high-quality and productive warm-season forages, such as Crabgrass, helps to increase forage production during the summer, reducing the forage gap commonly observed in cool-season forage systems. The impact can be even greater when fertilized with nitrogen, which is the most limiting nutrient for plant growth. For this reason, nitrogen fertilization is a powerful tool to enhance forage quality and productivity, especially in hayfields, where nutrient recycling is significantly lower than in grazing systems.

Harvest management is another factor that can affect the quality and productivity of forage species. Harvesting stimulates the production of new leaves by plants, and consequently, frequent harvests can improve the quality and productivity of hayfields. Based on that, this study analyzed how nitrogen rates of 0, 112, and 224 kg/ha and two harvest management (once or twice a year) may impact the quality and productivity of hayfields of Quick-N-Big and Mojo crabgrass varieties.
Nitrogen fertilization increased productivity and crude protein concentration in both crabgrass varieties. The combination of two harvests and 224 kg N/ha (H2N224) resulted in a total forage accumulation (TFA) of 7840 kg DM/ha/yr for Mojo in Year 1 and 8550 kg DM/ha/yr for Quick-N-Big in Year 2. However, nitrogen accelerated the plant’s maturity, decreasing crude protein and increasing fiber concentration. For this reason, when nitrogen is applied, two harvestings per year are recommended to maintain plants predominantly in the vegetative stage, increasing productivity and improving forage quality.
Plants growing fast also have a greater capacity to uptake nitrogen from the soil. Therefore, harvesting crabgrass hayfields twice a year is a method to improve forage quality and optimize nitrogen utilization, thereby contributing to an overall improvement in the production system efficiency.
The positive impact of nitrogen fertilization and two harvests on productivity and crude protein concentration resulted in a greater crude protein accumulation. Thus, intensifying harvest frequency (harvesting twice during the growing season) when N is applied in crabgrass pastures is essential to increase total forage accumulation and quality and, at the same time improve the N recovery. All these benefits together contribute to enhancing forage production efficiency and reducing animal supplementation costs.
The Journal of Agricultural Science Editorial Highlights are selected by the Editor-in-Chief and are freely available for one month. View the recent selections here.