Management of liquid swine manure: impact on mineral nitrogen dynamics and corn yield

ABSTRACT The agronomic efficiency of liquid swine manure (LSM) depends on the use of strategies to mitigate nitrogen (N) losses after its application to the soil, and thus preserve its fertilizing potential. In order to evaluate the injection of LSM into the soil and the addition of a nitrification inhibitor, as ways to increase its efficiency as a N source to the corn crop in the no-tillage system, an experiment was carried out under an Aluminofferic Red Latosol. The used treatments were: one control, surface application (total area) of LSM, injection of LSM in furrows, surface application (total area) of LSM + dicyandiamide (DCD), injection of LSM + DCD in furrows, and mineral fertilization. The mineral N in the soil and number of rows per ear, number of grains per row, 1,000-grain mass and grain yield for corn were evaluated. One day after the application of the treatments, the recovery of the mineral N in the soil with the injection of LSM exceeded by 10 kg ha-1 that observed with the superficial application. With DCD, the recovery of anionic forms (NO2- and NO3-) in the soil was lower in the first 20 days after the application, with the change in the N dynamics caused by DCD resulting in a higher content of mineral N at 30 days after sowing. The transformation rate for the anionic forms of mineral N in the soil is reduced with the addition of DCD. The injection of LSM with DCD does not differ from mineral fertilization, in terms of corn grain yield.

摘要 液态猪粪（liquid swine manure, LSM）的农艺效率依赖于其施入土壤后调控氮素（nitrogen, N）损失的策略，以此保障其肥效潜力。为评估液态猪粪土壤注入配施硝化抑制剂（nitrification inhibitor）作为提升免耕系统（no-tillage system）中玉米供氮效率的途径，本研究在富铝铁质红砖红壤（Aluminofferic Red Latosol）上开展田间试验。试验设置的处理包括：空白对照、液态猪粪全面地表撒施、液态猪粪沟施注入、液态猪粪全面地表撒施+双氰胺（dicyandiamide, DCD）、液态猪粪沟施注入+双氰胺（DCD），以及矿物肥料配施处理。本试验测定了土壤矿质氮（mineral N）含量、玉米穗行数、行粒数、千粒重及籽粒产量。结果显示：施用处理1天后，液态猪粪沟施注入处理的土壤矿质氮回收率较地表撒施处理高出10 kg·ha⁻¹。配施双氰胺（DCD）后，施用后前20天土壤中阴离子态氮（NO₂⁻与NO₃⁻）的回收率显著降低；双氰胺对氮素动态的调控使播种后30天的土壤矿质氮含量显著提升。添加双氰胺可降低土壤矿质氮向阴离子态的转化速率。配施双氰胺的液态猪粪沟施注入处理的玉米籽粒产量与矿物肥料配施处理无显著差异。