MINERALIZATION OF NITROGEN AND CARBON FROM ORGANIC COMPOST FROM ANIMAL PRODUCTION WASTE

ABSTRACT Elucidating the mineralization of organic composts makes it possible to understand the release of nutrients to plants. The objective of this study was to evaluate the mineralization of nitrogen (N) and carbon (C) from organic compost from residues of the production and slaughter of small ruminants, applied on a Neossolo Flúvico (Fluvents). The compost consists of remains of grass (forage), manure and slaughter residues such as blood, viscera and the carcass of goats and sheep. Under laboratory conditions, two experiments were conducted in a completely randomized design, considering the doses of organic compost at the following levels: zero; 3.75, 7.5, 15 and 30 Mg ha-1. For the N and C mineralization tests, 11 and 32 collection times (sampling periods) were evaluated, respectively. Inorganic N content (ammonium and nitrate) was measured in the N mineralization test, and CO2-C concentration was quantified in the C mineralization test. The largest increments between the applied doses of organic compost from residues of the production and slaughter of small ruminants were 70% and 69% for potentially mineralizable N and C, with amounts of 7.5 and 30 Mg ha-1 at doses of 3.75 and 7.5 Mg ha-1, respectively. Organic C and N from residues of the production and slaughter of small ruminants are rapidly mineralized in the soil (up to 45 days) due to their low C/N ratio.

摘要 阐明有机堆肥的矿化过程，有助于理解其向植物释放养分的机制。本研究旨在评估取自小型反刍动物生产与屠宰废弃物制备的有机堆肥中的氮（N）与碳（C）矿化过程，该堆肥施用于潮新成土（Neossolo Flúvico，Fluvents）。该堆肥原料包括牧草（饲草）残渣、粪便，以及山羊与绵羊的血液、内脏、胴体等屠宰废弃物。在实验室条件下，采用完全随机设计开展两组试验，设置的有机堆肥施用量梯度如下：0、3.75、7.5、15及30 Mg·ha⁻¹。针对氮矿化与碳矿化试验，分别设置了11个与32个采样时间点（采样周期）。氮矿化试验中测定了无机氮（铵态氮与硝态氮）含量，碳矿化试验中则定量检测了CO₂-C浓度。小型反刍动物生产与屠宰废弃物制备的有机堆肥中，潜在可矿化氮与潜在可矿化碳的最大增幅分别为70%与69%；其中潜在可矿化氮的最大增幅出现在3.75 Mg·ha⁻¹升至7.5 Mg·ha⁻¹的区间，潜在可矿化碳的最大增幅则出现在7.5 Mg·ha⁻¹升至30 Mg·ha⁻¹的区间。由于C/N比较低，取自小型反刍动物生产与屠宰废弃物的有机碳与氮在土壤中可被快速矿化（矿化过程最长可达45天）。