Effect of management practices on hydrology and nutrient losses from a tile-drained field under freeze-thaw conditions

冻融条件下管理措施对瓦排水田水文和养分损失的影响

• 批准号: RGPIN-2019-05662
• 负责人: Qi, Zhiming
• 金额: $ 3.13万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746294
• 关键词: Effect; management; practices; hydrology; nutrient

Statistics have shown that about 3.8 Gg of phosphorus (P) per year was exported to the St. Lawrence River in southern Quebec. This resulted in tolerable loads of P under provincial water quality standards (0.03 mg L-1) being exceeded at 68% of monitoring stations. Recent studies have shown that subsurface tile-drained cropland was the major contributor to water quality degradation in those regions. In eastern Canada these nutrient losses occurred mainly during the non-growing season of December to May. Notwithstanding the fact that macropore and soil nanoparticle-facilitated phosphorus transport are the key mechanisms of P losses from tile-drained regions, very few study have been conducted to investigate the hydrological processes and P losses under freeze-thaw conditions. On the other hand, management practices can be applied to mitigate nutrient losses during the non-growing season. Cover crops and reduced tillage are the primary options used on tile-drained fields; however, not all potential practices are useful, indeed, no till was found to increase dissolved phosphorus export from fields. This phenomenon might be attributed to there being more macropores in no-till fields. However, no study has been developed to focus on this question or combining those management practices with water table management strategies. Therefore, the objectives of this field study are to develop best management practices to mitigate P losses during the snowmelt and post-snowmelt periods and to understand the effect of winter hydrology and microporosity on nano-particle facilitated P loss in tile drainage. The experiment will be conducted at a 24-plot subsurface drainage site in Quebec with a complete randomized block design with a 2 x 2 x 2 factorial. The three factors are water table management, cropping system, and tillage. For each factor, there will be 2 levels: controlled drainage vs. free drainage, corn-soybean rotation with and without winter cover crop, and tandem disk + field cultivator versus no-till. Therefore, there will be 8 treatments and 3 plots will be assigned to each treatment. Weather, tile drainage, surface runoff, snowfall, snowpack, soil ice and liquid water content, snow sublimation, soil macroporosity and nano-particles, and all forms of P in water will be intensively measure, in particular during snowmelt and post-snowmelt period. Sponsored by the Canadian Foundation of Innovation, a NanoBrook Zetasizer, a scintillometer, and a Snow Pack Analyzer (SPA) were recently purchased to facilitate such measurements (value $247,208).

统计数据表明，每年约有3.8 gg的磷（P）出口到魁北克南部的圣劳伦斯河。这导致在省级水质标准标准（0.03 mg L-1）下，在监测站的68％中，P的载量超过了。最近的研究表明，地下瓷砖排水的农田是这些地区水质降解的主要因素。在加拿大东部，这些营养损失主要发生在12月至5月的非生长季节。尽管大孔和土壤纳米颗粒促磷的运输是P损失区域P损失的关键机制，但在冷冻条件下进行了水文过程和P损失。 另一方面，可以在非生长季节应用管理实践来减轻营养损失。覆盖农作物和耕作减少是瓷砖排水田中使用的主要选择；但是，并非所有潜在的实践都是有用的，实际上，没有发现会增加田间溶解的磷出口。这种现象可能归因于无耕地中有更多的大孔。但是，尚未开发任何研究来关注这个问题或将这些管理实践与地下水位管理策略相结合。 因此，这项现场研究的目标是开发最佳管理实践，以减轻融雪和季后赛后的P损失，并了解冬季水文学和微孔力对纳米粒子的影响，促进瓷砖排水中的P损失。该实验将在魁北克的24个图地下排水位点进行，其完整的随机块设计具有2 x 2 x 2阶乘。这三个因素是地下水位管理，种植系统和耕作。对于每个因素，都会有2个级别：受控排水与自由排水，有或没有冬季覆盖作物的玉米大豆旋转，以及串联磁盘 +田间耕地耕种器与无凹痕。因此，将有8种治疗方法，并将3个地块分配给每种治疗方法。天气，瓷砖排水，表面径流，降雪，积雪，土壤冰和液态水含量，降雪，土壤巨大质量和纳米粒子以及水中的所有形式的P都将是强度的测量，尤其是在雪融化和季后赛后期。最近购买了由加拿大创新基金会，闪光灯计和雪包分析仪（SPA）赞助的，以促进此类测量值（价值247,208美元）。