Dep. of Biological Systems Engineering, Univ. of Wisconsin-Madison, 460 Henry Mall, Madison, WI, 53706, USA.
Dep. of Soil Science, Univ. of Wisconsin-Madison, 1525 Observatory Drive, Madison, WI, 53706, USA.
J Environ Qual. 2022 Sep;51(5):978-989. doi: 10.1002/jeq2.20396. Epub 2022 Sep 8.
In cold regions, nutrient losses from dairy agroecosystems are a longstanding and recurring problem, especially when manure is applied during winter over snow-covered frozen soils. This study evaluated two tillage (fall chisel tillage [CT] and no-tillage [NT]) and three manure-type management treatments (unmanured control, liquid manure [<5% solids], and solid manure [>20% solids]). The liquid and solid manure used in this study were from the same animal species (Bos taurus) and facility. The six management treatments were field tested in south-central Wisconsin during the winters (November-April) of 2017-2018 and 2018-2019 with a complete factorial design. Seasonal runoff losses were significantly lower from fall CT compared with NT during both seasons. Manure applications (both liquid and solid) on top of snow significantly increased most of the nutrients (NH , dissolved reactive phosphorus, total Kjeldahl nitrogen, and total phosphorus) in runoff compared with unmanured control. Irrespective of tillage and multiple runoff events, solid manure was present on the surface for longer periods, potentially releasing nutrients each time it interacted with runoff. In contrast, liquid manure infiltrated the snowpack and was partly lost with snowmelt and infiltrated soil depending upon soil frost and surface conditions. Overall, results indicate that wintertime manure applications over snow-covered frozen soils pose a risk of nutrient loss irrespective of tillage and manure type, but in unavoidable situations, prioritizing tillage × manure type combination can help reduce losses.
在寒冷地区，奶制品农业生态系统的养分损失是一个长期存在且反复出现的问题，尤其是在冬季将粪肥施用于积雪覆盖的冻结土壤上时。本研究评估了两种耕作方式（秋季凿耕[CT]和免耕[NT]）和三种粪肥管理处理（无肥对照、液体粪肥[<5%固体]和固体粪肥[>20%固体]）。本研究中使用的液体和固体粪肥来自同一动物物种（Bos taurus）和设施。这六种管理处理在 2017-2018 年和 2018-2019 年冬季（11 月至 4 月）在威斯康星州中南部采用完全析因设计进行了田间测试。与免耕相比，在两个季节中，秋季 CT 产生的季节性径流水损失明显更低。在积雪上施用粪肥（无论是液体还是固体）都会显著增加径流水中的大部分养分（NH 、溶解反应性磷、总凯氏氮和总磷），与无肥对照相比。无论耕作方式和多次径流水事件如何，固体粪肥在表面停留的时间更长，每次与径流水相互作用时都可能释放养分。相比之下，液体粪肥渗入雪层，随着积雪融化和渗透土壤而部分流失，这取决于土壤冻结和地表状况。总体而言，结果表明，无论耕作方式和粪肥类型如何，冬季在积雪覆盖的冻结土壤上施用粪肥都会带来养分损失的风险，但在不可避免的情况下，优先考虑耕作×粪肥类型组合有助于减少损失。
