Crop Residue Management Challenges: A Special Issue Overview

The amount of crop residues that can be sustainability removed is highly variable and is a function of many factors including the soil, climatic, and plant characteristics. For example, leaving an insufficient amount of crop residue on the soil surface can be detrimental for soil quality, result in loss of soil organic matter (SOM), and increase soil erosion, whereas leaving excessive amounts can impair soil-seed contact, immobilize N, and/or keep soils cool and wet. This special issue evolved as an outcome of, “Crop Residues for Advanced Biofuels: Effects on Soil Carbon” workshop held in Sacramento, CA, in 2017. The goal of the special issue is to provide a forum for identifying knowledge gaps associated with crop residue management and to expand the discussion from a regional Midwestern U.S. to a global perspective. Several crop residue experiments as well as simulation modeling studies are included to examine effects of tillage, crop rotation, livestock grazing, and cover crops on greenhouse gas (GHG) emissions, crop yield, and soil or plant health. The special issue is divided into 4 sections that include (i) Estimating Crop Residue Removal and Modeling; (ii) Cultural Practice Impact on Soil Health; (iii) Residue Removal Impact on Soil and Plant Health; and (iv) Cultural Practice Impact on Carbon Storage and Greenhouse Gas Emissions

Variable crop residue management

Master of AgribusinessDepartment of Agricultural EconomicsJeffery R. WilliamsProduction agriculture is constantly evolving to become more efficient and productive. Crop residue serves as a valuable source of nutrients for the soil, but it is increasingly abundant with today’s enhanced crop genetics. If new technology can effectively provide a way to micro-manage crop residue levels within a field, the benefits will go beyond soil health. Surplus crop residue can be collected for secondary income while leaving the optimum amounts in the field to maintain the environment and soil health as well as promote future crop growth. The main objective of this study is to create a budget model that will determine the economic impact of crop residue removal on a controlled basis. The goals are to determine crop residue removal practices that are sustainable for the long-term, while also enhancing soil quality and increasing grain yield in future years. A sub-objective is to build a business case for producers to invest in variable crop residue management. The hypothesis presented in this study is that the increased complexity and price of a variable rate system is offset by more supplemental profits, increased crop yields, and better management of soil health and nutrients. The negative perceptions of crop residue removal include the fear of soil erosion or loss of soil organic matter. By developing a budget model that is easy to use, takes advantage of existing field data for inputs, and allows producers the ability to look at their operations on a sub-field level, this study aims to provide the necessary motivation to invest in new technology that will increase their productivity. By entering their site-specific crop residue return rate data into a budget model, along with prices and costs related to combine and auxiliary equipment, corn and corn stover, transportation and logistics, and nutrient replacement, they will come up with a return per acre for both constant rate and variable rate collection. The budget model determines whether it is economically viable to harvest crop residue from a continuous corn rotation at a variable rate across a field, rather than at a constant rate, using a producer’s own specific field data. To validate the concept, data from a joint study between John Deere and Iowa State is entered into the model. Prescriptions for corn stover return rates are provided from the study for pre-defined grid areas. Prescriptions are derived from a combination of data including grain yield, soil loss due to wind and water erosion, climate, topography, and soil sample data at time of planting (Nelson, et al. 2004). The average corn stover removal percentage was less for variable rate collection than constant rate collection, 26.05% to 31.85%. However, the assumption that grain yield and corn stover yield are positively correlated did not prove to be true in this case study. The variable rate plots had a lower average grain yield of 158.84 bushel/acre, compared to 160.46 for the constant rate plots, but they had more total corn stover available and therefore a higher return rate of 3.70 tons/acre, compared to 3.05 for the constant rate plots. This case study illustrates that less corn stover can be returned to the field through constant or variable rate collection while sustaining higher grain yields than a conventional harvest that would return all of the corn stover to the field. This case study demonstrates that variable rate collection can be more expensive than constant rate, but not in every situation. Every unique field site will require a specific crop residue management recommendation that is determined by both economic and environmental factors

Estimating Percent Residue Cover Using the Line-Transect Method

Leaving crop residue on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. Research in Nebraska and other midwestern states has shown that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by one-half of what it would be from residue-free conditions. Greater amounts of residue cover will further reduce erosion. Many Conservation Plans specify crop residue management or residue left on the soil surface as the primary erosion control method. Generally, the amount of cover required after planting ranges from 30 percent to as much as 85 percent. Thus, it is important to accurately determine percent residue cover to verify effective erosion control and compliance with a Conservation Plan. Residue cover cannot be estimated merely by looking across a field. Such estimates, often attempted from the road or edge of the field, grossly overestimate the actual amount of cover. Accurate estimates of residue cover can only be obtained from measurements taken within the field, while looking straight down at the soil and residue. Crop residue management, or leaving residue on the soil surface, is the most cost-effective method of reducing soil erosion available to Nebraska farmers. Accurate measurements of percent residue cover are needed to determine if enough cover is present to adequately reduce erosion and to comply with a Conservation Plan. The line-transect method is one of the easiest and most accurate methods of determining percent residue cover

Crop Residue Management- Part of Farming in the Future

Farming systems that manage crop residue are becoming more and more popular today. Interest and enthusiasm in crop residue management indicates that these farming practices will be part of farming in the future. Profit and conservation are driving these upward trends

Assessing the Effect of Soil and Water Conservation Practices on Runoff and Sediment Yield on Hunde Lafto watershed of Upper Wabi Shebelle Basin

A study was carried out at Hunde Lafto watershed to assess effect of Soil and Water Conservation practices on runoff and sediment yield. Soil and Water Assessment Tool (SWAT) model was used to assess the effectiveness of different Soil and Water Conservation (SWC) practices implemented in the watershed based on different scenarios (base line, stone bunds and crop residue management scenarios). The simulated sediment yield shows that soil loss rate range from 0-76.9 t/ha/yr with annual weighted average rate of 45.4 t/ha/yr. Parallel terrace (stone bunds) scenario reduced the total sediment yield from 10,978.7 t/yr to 3,734.26 t/yr relative to base simulation, which is equivalent to 65.9% decrease and reduces the surface runoff by 27% from 410.4 mm to 299.5 mm, increase base flow by 23% and lateral flow by 22.6% at outlet of watershed. While simulation of crop residue management scenario reduced total sediment yield to 4,299.84 t/yr from base simulation, which is equivalent to 60.8% reduction and the surface runoff by 23.5% from 410.4 mm to 313.6 mm, increase base flow by 18.6% and lateral flow by 19.9% at outlet. the benefits of crop residue management practices were more important in the watershed and recommended for farmers. Keywords: Soil and water conservation, Calibration and validation, simulation, Hunde Lafto catchment, Baseline scenario, runoff, sediment yield, watershed managemen

No-Till Corn-on-Corn Field Day Near Waverly

Iowa Learning Farms (ILF) will host a field day (2012 Field Day Guide) at the Mark Mueller farm near Waverly on Thursday, June 14, beginning at 11 a.m. the field day will focus on no-till conservation farming and crop residue management for optimum results

Results on life cycle assessments to determine impacts of agronomic management choices in the Cauca and Honduras CSV

The intense management of the crops, that characterizes current agricultural cropping systems, has resulted in increased concentrations of greenhouse gases (GHGs) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). In this study, we used the field-scale agricultural assessment model - Cool Farm Tool (CFT), to model GHG emissions and uptake estimates (Hillier et al., 2011). This tool combines different algorithms that integrate climate, soil and crop data and presents outputs on carbon footprints in a format that is accessible to non-experts. Furthermore, the CFT provides the possibility to compare GHG emissions and uptake estimates from different production sites and systems. Finally, the tool CFT enables crop producers and stakeholders to take a more informed and holistic approach to environmental sustainability in the agricultural sector

The effect of tillage and crop residue management on grain yields

Non-Peer Reviewe