- Agronomic: general hay and forage crops
- Production Systems: general crop production
For this project we developed a viable pasture-wheat intercropping (PWI) system with potential for managing post-contract Conservation Reserve Program (CRP) lands and enhancing grazing systems. Pasture-triticale intercropping (PTI), no-till annual rotation (NT) and hay production (HP) systems were also used for comparison of impacts on yield, profitability, and ecosystem services. Pasture cropping systems had overall higher productivity compared to NT monocultures and improved soil health compared to HP systems. Pasture cropping systems required higher fertilizer applications than NT but no herbicide applications. Net returns were higher for the PWI system than for NT and HP systems.
The Conservation Reserve Program has largely been successful in restoring many critical ecosystem functions to millions of acres through the conversion of vulnerable croplands to diverse perennial plant communities—primarily perennial grass and forb plantings. In terms of ecological benefits, it may be argued that simply leaving these former croplands idle under perennial grass cover would be best. Current CRP contracts, however, will expire on as many as 16.1 million acres in the US and on nearly 3 million acres in Kansas, Missouri and Nebraska by 2007. Aside from leaving the land idle and economically unproductive as it was during the contract period, land owners typically have two options for managing post-contract CRP lands.
Grazing or haying the CRP-perennial vegetation may be the best option for maintaining environmental benefits following contract expiration (Gilley et al., 1996), but can offer low economic returns. Another option is to convert the land back to annual cropland for greater economic return. In the past, nearly 66 percent of post-contract CRP grasslands have been converted to annual cropland with roughly 30 percent remaining in perennial cover (USDA-ERS, 2005).
Studies of the effects of CRP plantings on soil quality in Iowa, Minnesota, North Dakota and Washington illustrate the beneficial effects of perennial grass cover (Karlen and Parkin, 1996; Karlen et al, 1999). Deep rooted perennial grasses have greater access to soil resources over a longer growing season and in a larger soil volume than do annual crops such as winter wheat (Figure 1). Unfortunately, these benefits may be quickly lost once CRP plantings are converted back to annual cropping (Gilley et al., 1996; Randall et al., 1997). Shorter-lived and more shallow rooted, annual crops pose risks for significant nutrient losses below root zones (Dinnes et al., 2002; Crews, 2005). Their shorter growing season, as indicated by satellite images (National Agricultural Statistics Service, 2005), also leaves large landscapes devoid of living plant cover resulting in poor habitat for wildlife, greater risks of soil erosion, and high demands for tillage or herbicides.
Benefits of CRP are most quickly lost following conversion to cropland when tillage is used to kill the perennial cover (Gilley et al., 1996; Gewin et al., 1999). Direct conversion to no-till annual cropping (direct seeding) maintains the soil quality benefits of CRP for longer periods of time (Gewin et al., 1996; Karlen and Parkin, 1996) but requires high chemical inputs and sacrifices many benefits of perennial plants, such as wildlife habitat and effective water and nutrient management. In contrast, haying or grazing post-contract CRP lands has been shown to be the best option for maintaining soil and water quality and wildlife habitat benefits of CRP (Gilley et al., 1996). Leaving the perennial cover intact also eliminates the need for tillage or large inputs of herbicides.
The post-CRP contract dilemma of accepting lower economic returns from grazing or haying the perennial cover or accepting the loss of environmental benefits under annual cropping could be resolved by pasture-wheat intercropping (PWI). Pasture-wheat intercropping has been adopted by about 1000 growers in Australia as a means of conserving resources and increasing profits. At least one grower in north-central Kansas has independently developed a similar system. Another grower, Jim Duggan, a major participant on this project, has implemented a pasture-wheat intercrop study on his land with Dr. Glover.
The Australian experience. Historical overgrazing in central west New South Wales resulted in the displacement of deep-rooted perennial grasses and forbs with weedy annual species. This dramatic change in vegetation resulted in widespread land degradation. Reestablishment of perennial pastures was an effective means of reversing some of that degradation but pastures were not as profitable as annual crops. To resolve this dilemma, innovative farmers such as Col Seis began to direct seed cool season grain crops such as oats and wheat into their warm season pastures (www.grainandgraze.com.au/ColinSeis.htm).
Dr. Sarah Bruce and others (Bruce et al., 2005) found that, in comparison with conventional cropping practices, pasture-cropping leads to higher total ground cover during the cropping season and increased total biomass outside of the cropping season. The increase in ground cover and overall productivity relative to annual cropping reduces risks of wind and water erosion, reduces weed pressures and increases soil organic matter levels. Although pasture cropping can reduce total ground cover at times when compared to native pastures, pasture-cropping can increase total biomass and leaf litter. Pasture cropping also reduced nitrogen availability and soil water content compared to native pastures and conventional annual crops indicating that pasture-cropping may reduce the likelihood of water-logging, dryland salinity, loss of N through denitrification, and soil acidification developing—all are problems associated with annual cropping in the region.
There are now over 1000 Australian growers using some form of pasture cropping to combat the region’s severe land degradation problems. The system has also been adapted to non-native pasture systems such as intercropping with alfalfa and other perennial forage crops. Using the combination of perennials and annuals to integrate livestock and cropping operations on the same landscapes has improved profitability, increased management flexibility and maintained environmental benefits of continuous living plant cover.
Jim Duggan’s research efforts. Jim has been a no-till farmer for more than a decade. Although there are many benefits of no-till systems over conventional tillage, no-till systems still rely heavily on herbicides and fertilizers which can leak out into the surrounding environment. And, as with conventional systems, no-till annual cropping does not provide living ground cover over the entire year. This opens up opportunities for weed invasions and does not provide for wildlife habitat. Growing annual cover crops between crop cycles is difficult in the Great Plains given the variable weather patterns. Additionally, annual cover crops draw resources from the same soil layers as the annual crops and require additional field passes to plant and kill.
In response to these challenges, Mr. Duggan and Dr. Glover implemented research plots on a perennial hay meadow in November 2004. The purpose of this project was to determine how well a PWI system would perform relative to the other two land management practices Mr. Duggan was already using: haying perennial meadows and direct seeding annual crops.
Socio-economic Outcomes. In the long term, this project aims to maintain the ecological benefits of perennial plant cover while providing opportunities for significant grain yield on the same landscapes. This will be accomplished by drilling winter wheat (shallow-rooted and active during winter and spring months) directly into warm-season grasses (deep-rooted and active during summer months) shortly after haying or grazing. Referred to as Prairie-wheat Intercropping (PWI) in this proposal, this technique was independently developed by farmers in Australia and north-central Kansas. Impacts of PWI on yield and environmental benefits relative to standard haying systems, referred to here as HAY, and no-till annual rotation systems, referred to here as NT, will be documented. Diversification of farm operations on the same landscapes offers greater flexibility in dealing with annual weather variability, changes in market values of crop and livestock, and changes in purchased input costs.
Lands which have been enrolled in the Conservation Reserve Program (CRP) are the particular focus of this project although project outcomes would also be relevant for other perennial-based farming systems such as grazing operations. According to the United States Department of Agriculture’s Economic Research Service (USDA-ERS, 2005), CRP lands tend to have a net negative economic impact on rural communities during the contract period and, because they are often marginal lands, offer few management options without high risk of land degradation after contracts expire. New opportunities for producing solid yields of grain and hay on these marginal, formerly idle lands would have significant socio-economic impacts on farmers and rural businesses while maintaining the environmental benefits achieved during the contract period. Similar benefits could be realized from other lands currently used for perennial hay production or grazing and from marginal lands currently in annual grain production.
In the short to medium term, at least three growers will increase their understanding of PWI through direct participation in all aspects of the project. This core group of growers will be updated regularly on results, make recommendations, assist with management and help in getting information to other growers and researchers. At least 20 regional growers will become aware of PWI as an option for their post-contract CRP lands through field days and project reports, and we expect that at least 80 acres of PWI will be attempted on farms in the medium term. Mr. Duggan, the farmer who initiated this project, will also disseminate information among the no-till farming and organic beef producer communities in which he is active. Media attention for field days and subsequent inquiries will reach additional growers in Kansas, Nebraska and Missouri. An annual fall Prairie Festival at The Land Institute also attracts 400-600 visitors each year, many of whom are interested in or are engaged in farming practices. These visitors will be provided with field tours and discussions about pasture cropping systems.
These target outcomes may seem modest but given the untested potential of PWI practices in the southern portion of the North Central Region we prefer to match outreach efforts with research outcomes. Outcomes of a previous, related SARE-supported research project in the Northern Great Plains (LNC01-182) indicate more significant short to medium term outcomes are likely if field results are positive (Carr, 2003).
Scientific Outcomes. Natural resource professionals and the wider scientific community will become more aware of the agronomic, ecological and economic suitability of this system through sharing of preliminary data, published papers, conference presentations, and field tours. Initial reports will inspire more in-depth studies. Specifically, reports of research results linking seasonal soil water and nutrient availability to productivity of the grain and hay components will be produced for publication in peer-reviewed agronomy and/or soil science journals; an enterprise budget comparison will be compiled for publication in an agricultural economics journal; and changes in biodiversity associated with PWI practices will be summarized for publication in an ecology journal.
Research results will also be presented at national meetings of professional societies such as the Ecological Society of America, Soil Science Society of America, and Crop Science Society of America. The Land Institute hosts approximately 60 undergraduate and graduate students working in the areas of agronomy, ecology, range science, and soil science each year for workshops and field tours. This research project will be a key component for those student experiences.
We expect the NRCS State Technical Committee to consider adoption of PWI techniques for conversion of post-contract CRP fields, and for Conservation Security Program rules.