Response of no-till grain crops to pig slurry application methods and a nitrification inhibitor
Gonzatto, R., Aita, C., Bélanger, G., Chantigny, M.H., Miola, E.C.C., Pujol, S.B., Dessbesel, A., Giacomini, S.J. (2017). Response of no-till grain crops to pig slurry application methods and a nitrification inhibitor. Agronomy Journal, [online] 109(4), 1687-1696. http://dx.doi.org/10.2134/agronj2016.09.0547
Plain language summary
Nitrification inhibitors are increasingly used in agriculture to improve nitrogen use efficiency and decrease losses to environment through greenhouse gas emissions and nitrate leaching to groundwaters. The effects of application methods and nitrification inhibitors on the fertilizer value of pig slurry are still poorly documented, especially in no-till soils. In the context of collaboration with brazilian colleagues (e.g. projects #1259, 1642), we documented crop yield and N uptake in corn, oat and wheat for four years in no-till soils and compared mineral fertilization (reference treatment), surface application versus injection or pig slurry, and pig slurry with and without nitrification inhibitors. Crop yields were similar with pig slurry and mineral fertilizer, confirming the good fertilizer value of pig slurry. Compared with surface application, injection of pig slurry increased grain yields and nitrogen recovery by 29 to 68%, reflecting better conservation of pig slurry nitrogen when injected into the soil. Overall, crop performance was generally not affected by nitrification inhibitors, but they appeared to slightly improve performances of small cereal crops in periods when soils were colder. These results could be applied to the colder climate of Canada where small cereals are major cash crops.
The effects of application methods and nitrification inhibitors on the fertilizer value of pig slurry (PS) in no-till crops are still poorly documented. We evaluated grain and straw yield, and N accumulation of no-till corn (Zea mays L.), oat (Avena strigosa Schreb.), and wheat (Triticum aestivum L.) from 2011 to 2015 on a loam soil under a subtropical climate. The crops received either: (i) no fertilizer, no dicyandiamide (DCD) (control), (ii) surface-broadcast of urea-N (reference treatment), (iii) surface-broadcast pig slurry (PSs), (iv) PSs + DCD, (v) shallow-injected pig slurry (PSi), or (vi) PSi + DCD. Broadcast applications were performed manually whereas injection in furrows (≈10 cm) was made with a commercial applicator. Corn and wheat grain yields were similar with pig slurry and mineral fertilizer, confirming the good fertilizer value of pig slurry for no-till grain crops. Compared with surface broadcast, shallow injection of pig slurry increased grain yields of corn (+1.5 Mg ha–1) and wheat (+0.3 Mg ha–1), nitrogen agronomic efficiency (NAE) of corn (+9 kg grain kg–1 total N applied) and wheat (+2 kg grain kg–1 N), and apparent nitrogen recovery (ANR) in corn (46–68%) and wheat (29–38%). Crop performance was generally not affected by DCD, except for wheat in 2013 with increased yield (+15%), NAE (+2.7 kg grain kg–1 N), and ANR (31–39%). Pig slurry injection improved yield and N use efficiency of no-till grain crops, whereas DCD addition to pig slurry appeared more favorable for winter than summer crops.