Start Date: Oct 01, 2013
End Date: Aug 31, 2016
To compare weed treatment costs and weed treatment impacts between our rangeland weed IPM decision framework and conventional weed management approaches we will select two, 100 acre pastures on each of four ranches. Pastures represent a common ranch-scale management unit (i.e. producers make specific agricultural management decisions at the pasture level). In this ranch-scale study, ranches are blocks and pastures are the experimental unit. Each pasture in each block will be randomly assigned to be managed using our rangeland weed IPM decision framework or managed under current management decision processes. For pastures enrolled under our IPM decision framework, producers will design an IPM system using our published decision framework to select combinations of prevention tactics and weed management tools and strategies that are compatible with the economical and logistical constraints of the ranching enterprise and support other key management objectives (e.g. herd production, animal performance, drought preparedness). These treatments and strategies may include tactics for preventing weed spread, as well as timing, duration and intensity of grazing, herbicide application, seeding, targeted movement of grazing animals using supplement and temporary fencing, as well as targeted application of IPM treatments in different areas of the pasture. Pastures enrolled in conventional weed management will receive existing weed management practices, which may vary ranch to ranch. Cost of labor, materials and supplies will be tabulated for each pasture treatment and we will measure pre and post-treatment abundance and diversity of desired plant species and as well as weed species composition and abundance. Pre-treatment data will be collected fall of 2013 and treatment data will be collected spring of 2014, 2015 and 2016. Data will be analyzed using mixed-model Analysis of Variance with block and year as random factors in the model (SAS Institute Inc 2008). We will also evaluate, at a ranch scale, the benefits of rangeland weed IPM decision systems for enhancing multiple ecosystem services compared to conventional weed management approaches. We will use the same experimental pastures as those used in Research Objective 1 and also will add a third 100 ac reference pasture adjacent to each ranch that represents an intact, healthy rangeland agroecosystems. This will allow us to evaluate the degree to which IPM enhances ecosystem services relative to conventional weed management practices and allow us to quantify the degree to which IPM enhances these services relative to a healthy, intact rangeland agroecosystem. We will measure five characteristics that tie to key ecosystem services in these systems including: 1) Livestock carrying capacity 2) fine fuel loads and fuel load continuity 3) soil carbon dynamics 4) nitrogen retention and 5) insect diversity. Effects of pasture management systems (conventional vs. an IPM system for invasive plants) on multiple ecosystem services will assessed by using multivariate linear regression to analyze effects of pasture treatments on our five indicators of key ecosystem services.