Livestock and Forages: Essentials of Organic Farming?

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Andy Hammermeister, Ph.D.
Organic Agriculture Centre of Canada

Many farmers and researchers believe that organic farms can only be sustainable if they include perennial forages, such as a hay crop, livestock as part of the farm.

Including perennial forage as part of a crop rotation can be very beneficial. Most importantly, forage crops build soil organic matter. In addition to becoming a source of nutrients, this decaying plant material also improves soil structure. The soil can hold more water, is better aerated, and is less likely to erode or compact. A perennial forage crop also breaks the cycles of weeds, diseases and insect pests. If your farm does not include livestock, however, perennial forages may seem to be a costly practice that removes land from production for up to five years. In an organic system, selling hay reduces sustainability by removing nutrients that would otherwise stay on the farm and be used for cash crops. It can also be argued that the benefits of perennial forages can be achieved through careful management of crop rotations. Diversifying the rotation and growing fall-seeded and green manure crops are techniques commonly used to break pest cycles and sustain soils.

Livestock are also considered by many to be critical for sustaining an organic farm. Livestock not only diversify farm income but can utilize by-products of crop production. The manure from livestock can be a valuable resource for managing soil fertility in an organic system. The high availability of nutrients in manure, especially nitrogen and phosphorus, makes it very valuable in the prairies. In eastern Canada, however, the land base available for safely disposing of manure is smaller and nutrient loading may become a problem. Different animals use different feeds on the farm and therefore may have different roles. For example, ruminant animals, those that chew their cud such as sheep and cattle, can make good use of forage. Mongastric animals, those that have only one stomach such as chickens and pigs, are less effective at digesting forage and therefore need more grain or other protein sources in their diet. The manure produced by these two groups of animals can be quite different in nutrient content. Many farmers do not raise livestock for many reasons. Can an organic farm be sustainable without livestock? Or are they needed for cycling energy and nutrients on the farm?

The net benefit of perennial forages and livestock in an organic farming system is not clear. To help answer this question, the Organic Agriculture Centre of Canada and the University of Manitoba are partnering in organic farming systems research project. A four year crop rotation experiment has been established in Manitoba and Nova Scotia in 2002. The project is designed to address questions related to the economic, agronomic, and environmental benefits of including perennial forages and livestock on an organic farm. The basic crop rotation under study is wheat, soybean, barley, potato. The effects of one or two years of forage in the rotation are being tested by replacing soybean or soybean and barley with a forage crop suitable for the study area. The forages are underseeded in the prior crop. To examine the importance of livestock, composts made from manure of either ruminant animals or monogastric animals are used as a nutrient source in the crop rotations.

We will be monitoring the economics of these farming systems by keeping track of input costs and economic return. We will also monitor weed populations, crop diseases and pests and crop nutrition to examine the agronomic performance of each system. Environmental sustainability will be measured mostly by studying indicators of soil quality. Such indicators may include the kind and amount of organic matter in the soil and the measures of the microorganisms and small animals in the soil. At the end of the project we hope to have be able to make a clear recommendation about how important perennial forages and livestock are in an organic system.

At this time we can share some of our preliminary results from our plots in Nova Scotia in 2002. Firstly, we found that the plots that received no compost (alfalfa meal was used as a nitrogen source) were delayed in their early development compared with plots receiving compost. This delay in development seemed to result in a slightly lower crop yield and kernel weight. Interestingly, we also found that the number of weeds in a plot did not affect yield. What was more important was the size of weeds and their total weight.

For more information about this research please contact:
Andy Hammermeister
Organic Agriculture Centre of Canada
P.O. Box 550
Truro NS B2N 5E3
Ph: 902-893-8037
Email: ahammermeister@nsac.ca