- Agronomic: corn, sorghum (milo), soybeans, wheat
- Animal Production: stockpiled forages
- Crop Production: cover crops, double cropping, multiple cropping, no-till
- Education and Training: extension
- Energy: bioenergy and biofuels
- Farm Business Management: budgets/cost and returns, whole farm planning
- Production Systems: integrated crop and livestock systems
This experiment evaluates the yield and forage quality of twenty winter wheat (Triticum aestivumL.)based double cropping systems and five single cropping systems in Indiana. It is our hypothesis that winter wheat based cropping systems yield competitively to single cropping systems on a dry matter and grain basis, while providing winter cover for soil and producing high quality forage earlier in the season than traditional silage crops. Winter wheat exploits late fall and early spring opportunities for crop growth during a time-period when, traditionally, little other crop growth occurs in Indiana. Winter-wheat based crop programs also better distribute farm machinery and labor requirement across the year. Of the eleven11 forage and nine grain production systems, five were single-crop systems. Winter wheat exploits late fall and early spring for crop growth in which little else is productive in Indiana and better distributes farm machinery and labor requirement across the year.
Two winter wheat varieties and one triticale (X. Triticosecale Wittmack) were sown in late September at the Agronomy Center for Research and Education near West Lafayette, IN. in the fall of 2008 and 2009. Small grains were harvested at boot stage (middle May) and heading (early June) as whole plant green chop and silage, respectively and then in early July for grain and straw. Moisture content and yield were recorded from each small grain at each harvest. One of the winter wheat varieties was sown on the plots which were used for double crop systems. Immediately or soon after each wheat/triticale harvest date, second crops of corn or soybean or sorghum intended for either grain or silage production were planted in the wheat stubble or in bare ground control plots.
The forage quality of the three wheat harvests and all silage second crops were evaluated by ANKOM fiber analysis, Kjeltec crude protein, aerobic stability by temperature change and In vitro dry matter digestibility. Digestible dry matter (DDM) yield of small grains was maximized at the second wheat harvest (5.2 Mg ha-1 and 6.14 Mg ha-1 in 2009 and 2010, respectively). There were no significant differences between wheat and triticale DDM at the first two planting dates, however, triticale yielded more numerically than winter wheat. Of the second crops planted following the first wheat harvest, single crop silage corn yielded the most DDM (14.9 in 2009 and 14.0 in 2010 Mg ha-1). In 2010, single crop silage corn was similar to single crop silage sorghum. There was a significant yield loss associated with planting into wheat stubble: 22.8 and 25.7 % yield reduction for silage corn in both years and 27.7 and 23.6% for silage sorghum. At the second harvest date, there were no significant differences among corn, sorghum or sweet sorghum treatments in DDM. At the second date, all forage species were planted into wheat stubble. At the third planting, silage sorghum yielded more DDM than sweet sorghum, 6.5 MG ha-1 compared to 5.2 Mg ha-1, however this was not found in year two. In general, year two was more productive for silage crops.
Grain production for corn was negatively affected by both delayed planting (reduction of 11%) and planting into wheat stubble (reduction of 21%). Delay in planting to the third date affected soybean (43.2 % yield reduction), though wheat stubble did not affect grain yield at the first and second planting date. No change was observed in grain sorghum sown into wheat stubble or bare ground at the second planting date.
Agriculture in Indiana is dominated by corn and soybean production, which account for 38.4 and 35.1%, respectively of 5.99 million hectares in production (NASS, 2010). Diversifying production by incorporating winter wheat based cropping systems will address demand for animal feed while reaping the environmental benefits of no-till production. Winter wheat production utilizes radiation later in the fall and earlier in the spring (Beleyea et al., 1978), distributes labor and equipment use across more of the year, and provides environmental services of a winter cover crop. Silage production is a complex undertaking, involving specialized equipment, labor, and input costs which are not incurred in grain production and must be considered on a profitability basis prior to adoption (Rotz et al., 2003).
Forage species are evaluated by yield and fiber content. Year-to-year environmental variation has been identified as the major factor affecting total forage yield in wheat (Walker et al., 1990), forage corn (Zea mays) (Fairey, 1980; Wiersma et al., 1993) and sorghum (Sorghum bicolor) (Venuto and Kindiger, 2008). High levels of fiber have been linked to low digestibility, (Lewis et al., 2004) and lower animal weight gain (Brosh et al., 1989). Stage of maturity is a principle factor in forage quality (Walker et al., 1990; Black et al., 1980) due to the accumulation of lignin as plants mature (Barnes and Marten, 2012), though total yield increases across the season (Darby and Lauer, 2002). Therefore wheat harvested earlier in the season, though accumulating less dry matter, is highly digestible.
There have been yield losses observed when silage and grain corn crops are planted into standing wheat stubble (Opuku et al., 1997; Leep, 2002) and when planting is delayed (Fairey, 1980; Lewis et al., 2004; Lauer et al., 1999). However, straw mulch and wheat stubble preserve soil moisture (Opuku and Vyn, 1997, Wicks et al., 1997; Unger, 1984) which may be advantageous to second crops in a dry year. This effect is reduced or unseen in soybean (Hershman and Bachi, 1995; Caviglia et al., 2011). In dry areas, grain sorghum yield improves when planted into wheat stubble from the previous growing season (Unger, 1984).
Winter wheat based systems have the potential to be highly productive in Indiana. Grain and silage yields are depressed by the presence of wheat stubble, but on farms which support cattle, double-crop systems may be competitive with conventional single crop grain production systems.
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We accomplished our objectives/performance targets by successfully completing the experiment and collecting relevant data to explore this topic. Results have been presented at the American Forage and Grasslands Council Annual meeting, Agronomy Society meetings, Purdue University small grains field day and Hay Day, public defense at Purdue University, and published in the dissertation of Samantha Shoaf.