Fertilizer Source Effect on Silage Nutritive Value.

Manure and inorganic N fertilizer are often used together in silage production in dairy operations. Many dairy farms use both routinely without knowing the cost benefits of the combination. A trial was conducted to quantify the effect of semi-solid dairy cattle (Bos taurus) manure and urea on corn (Zea mays) silage nutritive value. Three replicates of organic/inorganic fertilizers treatments were evaluated on a commercial field near River Falls, WI. The study area was planted to 96 d maturity corn on May 31, 2017. The area was divided into four sections to include all treatments (T). Lengthwise one half of the area received 67.25 t ha^-1, and the second half received 134.5 t ha^-1 dairy manure fertilization; across the area, only one half received urea fertilization. This defined the four treatments [T1: 67.25 t manure ha^-1; T2: 134.5 t manure ha^-1; T3: 67.25 t manure ha^-1 plus 123 kg N ha^-1 (as urea); T4: 134.5 t manure ha^-1 plus 123 kg N ha^-1 (as urea)]. Three samples per treatment replication were collected at harvest for corn silage (65% DM), dried and processed for analysis. The forage nutritive value [neutral detergent fiber digestibility (NDFD), dry matter (DM), crude protein (CP), lignin] was determined using near infrared (NIR) diffuse reflectance spectrometer (SpectraStar XT 2600; wavelength range 680nm – 2600nm). The anticipated outcome of this study is the identification of the most appropriate fertilizer combination relative to desired silage nutritive value. The findings will aid producers in minimizing expenses in fertilizer while maximizing their silage nutritive value.