Transition strategies for an organic peanut-grain cropping system

Organic peanut (Arachis hypogaea) production has been centered in less-humid peanut producing areas where disease is less prevalent than in the Southeast. New disease resistant cultivars have opened new opportunities for organic markets in peanut production in the southeast. To become certified for organic production, land must go through a 3 year transitional period in which no inorganic inputs can be used, but growers will not receive price premiums since these are not certified crops during the transitional period. Developing cropping systems/rotations that will get growers through the transition period with some economical crops and minimal pest incidence heading into peanut production and land certification will be beneficial in opening up new acreage and market opportunities for peanuts and alternative grain crops such as pearl millet (Pennisetum glaucum) and cowpea (Vigna unguiculata).
Currently, demand for organic peanuts and feed grains greatly exceeds supply. In 2005, there was a shortage of nearly 5000 tons of organic peanuts in the United States (Culbreath, 2005), which equates to approximately 5000 acres of production. Similarly, domestic sales of organic poultry are increasing, resulting in an increasing demand for organic grain. In 2003, the Fieldale Farms Corporation, a southeastern poultry company, was short nearly 1,500 tons of organic feed grains and thus, was unable to market their drug free poultry as certified organic (Whittaker, 2003). In addition, alternative markets for peanut, such as boiled peanuts and hay, and grains, such as specialty bird seed and ethnic foods, show promise and may provide growers with additional market options.
Pearl millet is adapted to drought conditions and low fertility, and is an emerging crop in Georgia with potential in various production systems, including conventional row-crop agriculture and for biofuel production. It is a high quality grain that has excellent potential in poultry production and recreational industries, such as feed for wild game or pets. Reeves (SARE, 1993) reported that pearl millet provided similar energy and protein as tropical corn (Zea mays), and better levels of each as temperate corn. There is also potential for pearl millet to be sold into the ethnic food market, as it is a staple in India and many African countries. As a short season crop with a wide planting window, it is an excellent planting option as a double crop and between traditional crops where fields would normally be left fallow. A previous SARE project (SARE, 1993), Sustainable Whole Farm Grain/Silage Production Systems for the Southeast, reported that pearl millet was a viable silage and feed grain crop in the southern U.S., providing similar energy and protein as tropical corn. The SARE project (SARE, 1999), Disease and Insect Management Using New Crop Rotations for Sustainable Production of Row Crops in the Southeastern United States determined that pearl millet was a viable rotation alternative with soybean (Glycine max), wheat (Triticum aestivum), and canola (Brassica napus) in the southern U.S.A. Rotating pearl millet with peanut was found to reduce root knot nematode (Meloidogyne arenaria) infection and improves yield (Timper et al., 2007). Cowpea can also be a poor host to various races of root know nematode (Kirkpatrick and Morelock, 1987; Wang and McSorley, 2004) and could be used as a green manure, livestock feed, or human consumption (some varieties considered more suitable than others).
Increased organic peanut production in Georgia and most of the Southeast will depend on land that is not currently certified being brought into organic production. Most of the land that will be brought into organic peanut-grain production will be either 1) land currently in conventional production, 2) fallow or timber land that has not received synthetic inputs for at least three years and can be immediately certified as organic, and 3) pasture land that may or may not have received synthetic inputs in the prior three years. Each of these land use practices has different challenges, with differences in weed density and species competition and in soil quality. Most fields that have been in conventional production have high weed densities due to periodic fallowing and extended growing season that facilitates weed seed production. These fields typically have relatively low percentages of soil organic matter, soil microbial activities, endogenous minerals and nutrients, and relatively poor soil structure. Fallow fields can be expected to have higher percentages of soil organic matter, and other soil quality parameters compared to a conventionally managed field, but may have even more weed challenges since many of these fields are currently dominated by weedy species. Our preliminary on-farm study of peanut and pearl millet planted into a previously fallow field showed that frequent pre-planting cultivations significantly enhanced crop establishment, growth, and production, compared to no-till planting into heavy rye (Secale cereale) cover crop residue (E.G. Cantonwine, unpubl. data, 2006). Pasture land tends to have improved soil quality characteristics than a conventional field and fewer annual weeds contributing to the weed seed-bank than a fallow field, however, most perennial pastures are persistent grasses that resist management by cultivation due to their production of rhizomes and/or stolons.

Weeds, diseases, and insects are all major production hurdles for organic peanut, as chemical controls are the standard method in conventional production. However, preliminary research has shown promise in reducing some of these problems without the use of synthetic pesticides. Weeds may be controlled through stale seedbed techniques (Johnson and Mullinix, 1995; Johnson and Mullinix, 2000) and harrowing (Wilson et al., 1993). Mechanical cultivation is one of the most important management decisions for organic producers (Ferrell et al., 2011; Hauser et al., 1973; Smith et al., 2000) with sweep and flex-tine cultivators (Reddiex et al., 2001) currently offering the most promise in organic peanut production according to our preliminary research (W.C. Johnson III, unpubl. data, 2008-2009; R.S. Tubbs, unpubl. data, 2009-2010). Likewise, crop rotation has proven an effective tool to suppress weeds (Hauser et al., 1974; Johnson and Mullinix, 1997; Menges, 1987). Yet, for disease control, genotype selection is the most viable option as bred resistance to some of the most damaging pathogens is what made organic production of peanut a possibility in the first place (Branch and Culbreath, 2008; Wynne et al., 1991). There are some approved fungicides for combating diseases, which have shown some promise as either seed treatments or foliar applications (Cantonwine et al., 2008; A.K. Culbreath, unpubl. data, 2008-2009; R.S. Tubbs, unpubl. data, 2009-2010). Although, rotation is again an important factor for disrupting insect and disease cycles (Kemerait et al., 2011; Porter et al., 1984). In addition, most insect pests of peanut, such as fall armyworm (Spodoptera frugiperda), velvetbean caterpillar (Anticarsia gemmatalis), corn earworm (Helicoverpa zea), southern corn rootworm (Diabrotica undecimpunctata), and cutworm (Agrotis subterranea), can largely be managed with irrigation in most years (Adams, 2009; Womack, 1981), while insecticide application is not a common practice even in conventional production since these pests rarely exceed economic thresholds.

Organic products are accompanied with a price premium, often making this production type economically competitive and sometimes superior to conventional production systems despite greater risk of lower yields. There is no exception for peanut, as a recent organic peanut crop in Georgia was contracted at two to three times the average contract price of conventional peanuts (N.B. Smith, pers. commun.). Coupled with low input costs since herbicide and fungicide programs are essentially eliminated (aside from the few acceptable inputs available), there is certainly an opportunity for growers to capitalize financially with organic management. Although, there are cautions to this, as there are usually increased fuel costs from regular cultivation, plus a necessity for some hand-weeding, which is a highly expensive input. Likewise, the transitional period requires the adherence to organic production guidelines, but does not qualify as a certified organic crop and thus cannot command the price premiums that accompany certification during the transitional period. Often, any potential profits/gains anticipated upon certification are needed to offset losses incurred during the transitional period. Thus, the entire system should be considered in advance before a producer makes a concerted effort toward organic production.
The importance of an organic production system for peanuts in the southeastern U.S. is paramount though. With the only currently available supply of products coming from the southwestern peanut producing region (primarily concentrated in New Mexico and Texas), this requires shipping of products to the east which likewise increases fuel expenditures and costs. As one of the primary goals of low input agricultural systems such as organic production is to minimize environmental pollution, the burning of additional fossil fuels to move products is contradictory to this principle, especially with many peanut processing facilities located in the southeastern region. Thus, creating a more regional, localized supply is critical to the long-term sustainability of meeting the demand for organic peanut products.