Slurry injection with nitrification inhibitor in maize: Plant phosphorus, zinc, and manganese status

ABSTRACT

Slurry injection below the maize (Zea mays L.) row may substitute a mineral nitrogen (N) phosphorus (P) starter fertilizer (MSF) and thus reduce nutrient surpluses in regions with intensive livestock husbandry. We investigated the plant P, zinc (Zn), and manganese (Mn) status compared to the current farm practice. In 2014 and 2015 field trials were conducted to evaluate plant nutrient status at different growth stages. Besides an unfertilized control, two slurry injection treatments (±nitrification inhibitor (NI)) were compared to slurry broadcast application plus MSF. In both experiments NI addition significantly increased nutrient concentrations during early growth (6-leaf 2015: +33% P, +25% Zn, +39% Mn). Under P deficiency due to cold weather conditions broadcast application showed higher P uptake until 6-leaf (36–58%), while it was lower at 8- (32%) and 10-leaf (19%) stage compared to slurry injection (+NI). Zn availability was enhanced for slurry injection (+NI) during early growth and Zn and Mn uptakes were higher at harvest. Slurry injection decreased P balances by 10–14 kg P ha⁻¹, while Zn and Mn balances were excessive independent of treatments. Slurry injection (+NI) can substitute a MSF without affecting early growth and enhances the Zn and Mn status. This new fertilizing strategy enables farmers to reduce P surpluses.

KEYWORDS:

• fertilizer placement
• starter fertilizer
• nutrient balances
• rhizosphere acidification
• micronutrients
• recovery efficiency

Acknowledgments

We are grateful to the German Federal Environmental Foundation (Deutsche Bundesstiftung Umwelt), Osnabrueck, for financing the project “Optimizing the nitrogen and phosphate use efficiencies from liquid manure by slurry injection to reduce environmental pollution” (grant number: 30364–34). EuroChem Agro GmbH, Mannheim, thankfully granted additional support. We thank our scientific assistants and students for supporting plant sampling and preparation. Further on, we acknowledge the laboratory team, as well as Herbert Pralle for his assistance with the statistical analysis.

Additional information

Funding

This work was supported by the Deutsche Bundesstiftung Umwelt, (30364-34).