Corn silage is a popular forage for ruminant animals because it is high in energy and digestibility. Maximizing tonnage is a key factor when farmers grow corn for silage.
Using higher corn populations for silage may help manage phosphorus (P) in heavily manured areas.
The objective of this study was to determine the effect of seeding rate on irrigated corn silage yield and P uptake.
RESEARCH SITE DETAILS
The study was set up as a randomized complete block with three replications.
A 108-day relative maturity corn product was planted in 30-inch row spacing at 24,000, 28,000, 32,000, 36,000, 40,000, 44,000, and 48,000 seeds/acre.
Corn was sprinkler irrigated and weeds were controlled as needed. No fungicides or insecticides were applied.
Silage was hand-harvested one inch above the soil surface to provide a representative sample (Figures 1 and 2) and chopped with a silage chopper.
Total biomass was collected and weighed, a subsample was dried, and dry matter weight was calculated for each seeding rate.
Pounds of total P removed was then calculated.
UNDERSTANDING THE RESULTS
Average silage dry matter yield increased significantly with increased seeding rates (Figure 3) with the highest tonnage recorded with the 48,000 seeds/acre population.
Increased seeding rates also increased the lb/acre of P removed with the lowest amount recorded with the lowest population of 24,000 seeds/acre (Figure 4).
Using higher corn populations can be beneficial for increasing tonnage as well as removing P from the soil.
Producers can utilize high corn silage populations to increase P removal and help manage soil P levels on fields where manure is applied.
Monitoring crop P concentrations is essential for balancing feed rations and accurately estimating crop P removal, estimates that are in turn necessary for optimizing manure management and avoiding or mitigating soil P enrichment for protection of water resources. Increasing the amount of P removal in harvested crops can help slow the rate at which soil test P increases and help reduce the soil P over time.