Legume recovery in pastures following broadleaf weed control

入侵物种是限制牧草生产的牧场中普遍存在的问题。虽然除草剂对杂草仍然有效，但除草剂也会以最低的成本去除已知增加产量的有益豆类。虽然迅速恢复豆科植物是一个重要的目标，但杂草控制后豆科植物在牧场重新建立的能力取决于几个因素。它们包括喷洒后除草剂降解的速度，土壤中有活力的豆类种子的存在，以及在田间条件下有利于豆类幼苗出苗和生长所需的特定生长条件。我们结合实地实验（短期和长期）和补充温室试验，以1）量化两种新除草剂的降解（环丙嘧啶酸和氯氨吡啶酸）与'残留'的性质，2）评估其对两种常见豆类的出苗和存活的影响（紫花苜蓿和白色三叶草）施用后的环境影响评价（光和水分）对豆科植物出苗、生长和存活的影响; 4）记录喷洒后牧场植物物种组成的长期变化; 5）描述北方温带牧场的土壤种子库，包括豆科植物的丰富程度。这些信息将用于帮助种植者有效地重新种植豆类作物，并保持生产力和牧场生物多样性。

Invasive species are a widespread problem in pastures limiting forage production. While herbicides remain effective against weeds, herbicides also remove beneficial legumes known to increase production at minimal cost. Although prompt return of legumes is an important goal, the ability of legumes to re-establish in pastures following weed control depends on several factors. They include the rate of herbicide degradation following spraying, the presence of viable legume seeds in the soil, and the specific growing conditions needed to favor legume seedling emergence and growth under field conditions. We use a combination of field experiments (short and long-term) and complementary greenhouse trials to 1) quantify the degradation of two new herbicides (aminocyclopyrachlor and aminopyralid) with 'residual' properties, 2) assess their effect on the emergence and survival of two common legumes (alfalfa and white clover) following application, 3) evaluate the effect of environment (light and moisture) on legume seedling emergence, growth and survival, 4) document long-term changes in plant species composition of pasture following spraying, and 5) describe the soil seed bank in northern temperate pastures, including the abundance of legumes. Information will be used to assist growers to effectively re-establish legume and maintain productivity and pasture biodiversity.