By Rick Kersbergen
Crops and livestock have historically been integrated in farming systems. However, in the last 50 years there has been a trend towards specialization of single crops, diversified vegetables or livestock. In many cases, this specialization has also developed into consolidation of commodity production.
For example, in many areas we see vegetable production focused in one county, and dairy or other livestock production in another. This consolidation creates a reliance on commercial fertilizer in the vegetable county for fertility, and a concentration of manure nutrients in the livestock counties. In the livestock areas the largest source of nutrients that end up in the soil may actually be from imported grain purchased to feed dairy cows and young stock. If the nutrients going into livestock operations are coming from outside the area, it can potentially lead to excesses that cause over-fertility, environmental concerns and non-point source pollution.
Recently there has been increased discussion of diversification and re-integration of crop and livestock operations. Two scales of integration are often discussed: (1) within-farm integration, where a crop or dairy operation diversifies and adds another enterprise and (2) among-farm integration, or “coupled” farms, where two or more operations share land, manure nutrients, forage and grain crops grown in rotations. These coupled operations allow individual specialization, but facilitate sharing of nutrient and land resources, hopefully benefiting both operations.
Benefits of Integrating Livestock and Vegetable Operations
When evaluating the benefits of integrated systems it is obvious that organic vegetable producers would benefit from the improved flow of nutrients from manure produced from a livestock enterprise. This is especially true when one considers areas that are deficient in soil phosphorus. Feeding forages and grains through ruminants will improve phosphorus availability.
Nitrogen from manure is also fairly rapidly available to plants during the growing season. This, of course, is dependent on the type of manure and bedding content. Poultry manure (cage layer) will contain very little carbon and have high nitrogen availability, while beef, sheep or horse manure with high amounts of carbonaceous material such as sawdust or shavings may “tie up” nitrogen when applied to the soil.
More specifically, what are the benefits of adding livestock to vegetable operations?
1) A source of nutrients that can be used for direct application and/or composting. By combining livestock and vegetable production, the whole farm nutrient balance of imports and exports becomes more even.
2) Along with nutrients, manure and compost applications tend to improve soil organic matter, biological activity and potential disease suppression. This improved soil health will manifest itself quickly and include improved soil nutrient cycling, improved soil structure, better water holding capacity in droughty soils and improved drainage in heavy soils.
3) Livestock operations improve the potential for profit in lands that are in a “sod” rotation. Sod crops help to build soil structure (grass roots) and soil drainage (legumes/alfalfa). Sod crops high in legume content will also provide a source of nitrogen when those fields are returned to row crop production.
4) Livestock provide a use for crop residue and waste or cull vegetable crops. This can help reduce disease while providing a “cheap” source of feed for livestock. Cows turned into a field of pumpkins in November utilize great feed and help vegetable producers clean up a field!
5) Grain crops used by vegetable operators as cover crops can fit well into livestock rations. Winter grain crops provide fall nutrient catch, weed control in both fall and spring, and can be undersown with clover or other legumes to provide nitrogen in subsequent rotations and a sod crop establishment with minimum tillage.
6) Adding livestock products to the marketing mix can help improve cash flow in the winter and add a new aspect to CSA operations.
7) While not always discussed, successful “coupled” animal/vegetable operations can also help to build community with a farm region. Coupled operations also have the option of sharing machinery resources and labor during busy periods.
Livestock Waste Can be an Issue
While there are many positives to integrating livestock and vegetable operations, there are also some risks and issues. Most involve the use and handling of livestock wastes and effluent from feeding operations.
Organic operations have specific guidelines for the use of manure and manure composts. Un-composted manure is permitted under organic rules if it is applied 120 days prior to harvest of crops where the edible portion has direct contact with the soil or soil particles, or at least 90 days prior for crops where the edible portion does not have direct contact with the soil or soil particles. Livestock manure may be used on crops that are not for human consumption without waiting periods before harvest. Manure tea and liquid manure have the same restrictions. Composting eliminates these “waiting” periods, but involves time and temperature monitoring for pathogen reduction.
Additionally, new USDA guidelines for GAP (Good Agricultural Practices) discourage the use of manure or adjacency with livestock operations. With many markets now demanding GAP certification, many vegetable producers may be hesitant to integrate livestock and vegetables. While GAP guidelines discourage integration, they do not eliminate the potential. GAP certification and the audit process is based on a point system. Bringing manure and animals into your vegetable operation means that you lose points in one section; in order for your operation to pass the audit, it must be “tighter” in other food safety management.
Below are links to information regarding food safety and the use on manure in vegetable operations, as well as information about GAP audits and the certification process.
Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits and Vegetables
Food Safety Begins on the Farm
National GAPS Educational Materials at Cornell
USDA Good Agricultural Practices & Good Handling Practices Audit Verification Checklist
Rick Kersbergen is Professor of Sustainable Dairy and Forage Systems, University of Maine Extension.
What is GAP?
In this piece Rick refers to “GAP,” while Chris Blanchard’s article in this issue talks about “food safety practices.” What is GAP, and how does it relate to food safety? This is what Chris Blanchard has to say:
GAP is short for “Good Agricultural Practices.” Its acronymic cousin, GHP (say ghip with a hard g), is short for “Good Handling Practices.” Both are related to microbiological and physical food safety in fresh vegetable production.
In California and Arizona, it is most common for vegetables to be produced by one company and sold — sometimes in the field –to another company for the kinds of washing and packing activities that smaller farms handle internally.
The USDA-AMS offers a “GAP/GHPs” audit. So do a number of private companies. But at this time, there is no such thing as “GAP-certified”; you can pass a GAPs audit, but those vary widely from auditor to auditor. Likewise, there is no official coda of “GAPs”; there are a number of different standards to which a grower can be audited for their food safety practices, and there are a number of different guides out there regarding what constitutes good food safety practices.
So, GAP is basically shorthand for saying, “farming practices that reduce the risk of microbiological contamination of fresh produce.” Or, according to Wikipedia, “Good Agricultural Practices (GAP) are specific methods which, when applied to agriculture, create food for consumers or further processing that is safe and wholesome. While are numerous competing definitions of what methods constitute ‘Good Agricultural Practices’ there are several broadly accepted schemes that producers can adhere to.”