Does fall manure injection cause differential growth and forage nutritive value in small grains?

Abstract

Producers utilizing fall manure injection have reported increased growth and greenness in small grains growing on the injection band compared to small grains growing between injection bands. To determine how producers utilizing fall manure injection in small grains should manage potential differential growth, 24 sites under fall manure injection were established. Soil samples were taken in‐band and between‐band 1 month after manure application and at silage harvest for soil NO3‐N. Small grain growth stage was assessed 1 month after planting and at silage harvest, while dry matter (DM) yield and forage nutritive value parameters were assessed at silage harvest. Soil NO3‐N was elevated in‐band compared to between‐band 1 month after manure application (p < 0.05); however, this did not persist until silage harvest. No differences in growth stage were observed 1 month after planting in 2021; however, growth stage means were consistently elevated in‐band in 2022, likely due to earlier planting dates in 2022 compared to 2021. Growth stage at harvest was the same in‐band and between‐band at each site. Small grain DM yield was only increased in‐band compared to between‐band in three of 24 sites. Two of the three sites planted with wheat (Triticum aestivum L.) showed significantly increased DM yield in‐band, suggesting DM yield response could be species dependent. No consistent differences in forage nutritive value parameters were observed. As no consistent differences in small grain DM yield and forage nutritive value were found at harvest, we recommend no changes to management practices for producers utilizing fall manure injection in small grains.