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© 2002 Plant Management Network.
Accepted for publication 9 December 2002. Published 18 December 2002.

Integrating a Double-Cropped Winter Annual Forage into a Corn-Soybean Rotation

Kurt D. Thelen and Richard H. Leep, Department of Crop and Soil Sciences, Michigan State University, Plant and Soil Science Building, East Lansing 48824

Corresponding author: Kurt D. Thelen. thelenk3@msu.edu

Thelen, K. D., and Leep, R. H. 2002. Integrating a double-cropped winter annual forage into a corn-soybean rotation. Online. Crop Management doi:10.1094/CM-2002-1218-01-RS.

Abstract

Consolidation in the dairy and livestock industry in the North Central states has resulted in a need for producers to increase forage production per unit of land base. Using a winter annual forage crop in a corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cropping system could add a third harvestable crop in a two-year rotation period resulting in increased forage production per unit of land base. The objective of this study was to: (1) evaluate the yield and quality of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.) crops harvested as an early spring forage; and (2) evaluate the affect on subsequent rotational crop yield. Winter wheat and rye forage yielded from 2.7 to 1.7 ton/acre. Winter wheat and rye forage reduced yields of subsequently planted corn and corn silage compared to treatments that did not have a double-crop winter annual forage. However, soybean yield was not reduced when preceded by the winter annual forage. These results suggest that growers can effectively utilize winter wheat or rye as a double-crop forage in corn-soybean cropping systems when the winter annual forage crop precedes soybean in the rotation.

In recent years, the dairy and livestock industry in the northern corn-belt has undergone a consolidation to fewer but larger production units (4). This consolidation has resulted in a need to increase forage production per unit of land base in proximity to the dairy and livestock production facilities. A possible means of doing this is to double-crop a winter annual forage crop with corn or soybean.

The practice of double-cropping soybean with winter wheat harvested for grain is a common practice in the southern corn-belt states (12), however, the shorter growing season in the northern corn-belt limits double-crop options. Chan et al. (5) suggested that a form of double-cropping known as relay intercropping could allow double-cropping to occur further north in the corn belt. Relay intercropping is defined as growing two or more crops simultaneously during part of the life cycle of each (1). Studies in the northern corn-belt states of Wisconsin (11) and Ohio (10) found that relay intercropped soybeans yielded less than monocrop soybeans in systems where the winter annual wheat was harvested for grain. Little information on multiple cropping systems is available in the literature regarding the effect on rotational crop yields when the winter annual crop is harvested as early spring forage.

Bruckner and Raymer (2) reported no difference in mean forage yields of rye, wheat, oats (Avena sativa L.), and triticale (× Triticosecale Wittmack). However, the authors reported that rye was the best-adapted species for forage in high-stress, low-yield environments and wheat was the best-adapted species to low-stress, high yield environments. In comparing soft red winter wheat cultivars with hard red winter wheat, Carver et al. (3) reported that soft red winter wheat cultivars produced 30% more winter forage, but hard red winter wheat cultivars produced 26% more late winter regrowth. They concluded that both soft and hard red winter cultivars appear equally suited as germplasm sources for genetic improvement of wheat forage capacity.

The objective of this study was to evaluate the yield and quality of winter wheat and rye crops harvested as early spring forage and to evaluate their affect on double-cropped corn, corn silage, and soybean yield.

Field trials were conducted in 2000 and 2001, on a Capac loam soil (fine-loamy, mixed, mesic Aeric Ochre-qualf) at the Michigan State University Research Farm in East Lansing, Michigan. In both years of the study, corn silage preceded the fall-planted winter annual forage crop. Plots were arranged in a randomized complete block, split plot design with four replications. The three rotational crops (corn grain, corn silage, and soybean) planted after harvest of the winter annual forage crops represented the main plots. The split plots consisted of the winter annual forage crops (early-cut wheat, late-cut wheat, and rye) and a check plot that was not seeded to a winter annual, with the residue from the previous crop of corn silage left undisturbed. The split plot size was 10 × 40 ft.

The wheat variety was ‘Harus,’ an early-maturing awnless soft white winter wheat developed at the Agriculture Canada Research Station in Harrow. The forage rye variety used was ‘Wheeler’ which was released by the Michigan Agricultural Experiment Station. The winter annual forages were planted on 28 September in 1999 and 13 October in 2000. The wheat was planted at 120 lb/acre and the rye at 112 lb/acre. Each forage plot received 46 lb/acre of elemental N applied as granular urea (46-0-0) at green-up the following spring. The early-cut wheat forage was harvested at the boot stage (Feeke’s scale 10.0), late-cut wheat was harvested at the early head stage (Feeke’s scale 10.1), and rye was harvested at the early boot stage (Feeke’s scale 9.0). The respective harvest dates for 2000 were 11 May, 22 May, and 26 April. The harvest dates for 2001 were 19 May, 24 May, and 7 May, respectively, for the early-cut wheat, late-cut wheat, and rye. A Carter flail harvester (Carter Manufacturing Co. Inc., Brookston, IN) was used to harvest the winter annual forage plots. Forage was harvested at a height of 3.5 inches from the soil surface. Moisture content was determined by collecting pre and post weights of a 1-lb sample of the harvested forage dried at 140°F for 72 hours.

Forage samples used for nutritive evaluation were collected at the time of harvest by hand clipping 0.5 lb of forage. Samples were dried at 140°F for 48 hr, ground to pass through 2-mm screen in a Wiley Grinding Mill (Christy and Moris, Chelmsford UK) and passed through a UDY Cyclone Mill (Udy Corp., Fort Collins, CO.) with a 2-mm screen. A sub-sample of 0.7 oz was retained for analysis. Total N was determined by the Hach modified Kjeldahl procedure (8,13), and crude protein (CP) was estimated by multiplying the N content by 6.25. The Goering and Van Soest (7) method was used for neutral detergent fiber (NDF) and acid detergent fiber (ADF) determination with the addition of 0.03 fluid oz of alpha-amylase to the neutral detergent solution for the breakdown of starch. Dry matter (DM) was determined by weighing 0.02 oz of sample into ceramic crucibles and drying at 212°F for 12 hrs. Ash content was determined by igniting the samples in a muffle furnace for 6 hours.

The double-crop corn and soybeans in the rye and early-cut wheat forage plots were planted on 11 May in 2000 and 19 May in 2001. The rotational double-crops following the late-cut wheat forage were planted on 22 May in 2000 and 24 May in 2001. Since planting of the rotational crops in the control plots did not have to wait for harvest of a winter annual forage, they were planted slightly earlier than the plots that had a winter annual forage when soil conditions allowed. The control plots were planted to rotational corn and corn silage on 29 April 2000 and 5 May 2001 and were planted to soybean on 11 May 2000 and 5 May 2001. The rotational crops were planted with a no-till planter. Corn was planted in 30-inch rows at 30,000 seed/acre for both the corn grain and corn silage treatments. Soybeans were planted in 15-inch rows at 180,000 seed/acre. Plots planted to corn received 140 lb/acre of elemental N applied as a liquid solution (28% urea-ammonium nitrate). The rotational double-crops were harvested with mechanical equipment. The corn silage was harvested when the grain was approximately at the 2/3 milk line (14). Corn grain moisture content and field weights were automatically measured by a GrainGageTM, HarvestData SystemTM mounted on a plot combine. Grain yields are reported at 15.5 % moisture.

All data were analyzed with the analysis of variance (ANOVA) and the General Linear Models in SAS Statistical Software Package version 6.12 (1989-1996 SAS Institute Inc., Cary, NC). Mean separation between variables was obtained using Tukey's Least Significant Difference Test. Effects were considered significant in all statistical calculations for P-values < 0.05. For the economic analyses, the input costs used were the actual costs accrued. Equipment costs reflect 2000 prices as reported by Dartt and Schwab (6). The cash receipts reflect the 2000 five-year average commodity price as reported by the Michigan Agricultural Statistics Service. Net return to land and management was obtained by subtracting equipment and input costs from cash receipts.

Precipitation levels were somewhat lower in the fall of 1999 and somewhat higher in the fall of 2000 than 30-yr average levels (Table 1), however, in both years the climate was favorable for establishment of the winter annual forages. Similarly, both years provided near-normal seasonal precipitation and growing degree unit (GDU) accumulation for the rotational double-crops although the months of July and August were slightly dryer than normal in the 2001 growing season (Table 1).

Table 1. Monthly precipitation and growing degree unit (GDU) accumulation for the 1999 through 2001 winter annual and rotational crop growing seasons at the experimental location.* Thirty-year means have been included for comparison (1971-2000).

* Data recorded at the Horticultural Research Station, East Lansing, MI.

** GDU calculated for corn at a base 50°F, with 50°F and 86°F minimum and maximum temperatures.

Both early- and late-cut wheat had a higher forage yield than the rye (Table 2). Dry matter yield was 1.7 ton/acre, 2.6 ton/acre, and 2.7 ton/acre, respectively, for the rye, early-cut wheat, and late-cut wheat forage averaged across years. The rye forage was harvested on average 13 and 21 days before the early-cut wheat and late-cut wheat forages. Similarly, winter annual forage quality was dependent on date of harvest. The early-cut forage had higher levels of CP and lower NDF and ADF levels (Table 2). The observed negative correlation between forage quality and cutting date is consistent with previous reports in the literature on grass forages (9).

Table 2. Winter annual forage yield and quality. Values are averaged across year and replication. Means followed by the same letter are not significantly different at P = 0.05.

* ADF = acid detergent fiber; NDF = neutral detergent fiber; CP = crude protein.

The affect of the winter annual forage crop on the yield of double-cropped corn grain, corn silage, and soybean was also evaluated (Table 3). The rotational double-crops were planted in the spring immediately following harvest of the winter annual forage crop. Yields of the rotational double-crops were compared to the check plots, which did not have a winter annual crop preceding the corn, corn silage, and soybean rotational crop. Early- and late-cut wheat forage reduced double-crop corn grain yield more than the rye. Similarly, the early- and late-cut wheat forage reduced the yield of the double-crop corn silage. The later harvest date for the wheat forage may have depleted soil moisture more than the rye plots, which were harvested an average of 13 and 21 days before the early- and late-cut wheat. The later removal of the wheat forage may have contributed to the lower corn grain and silage yields in the wheat forage double-crop system as compared to the rye forage double-crop system. Additionally, the double-crop corn following the late wheat forage was planted 11 and 5 days later in 2000 and 2001 than the double-crop corn following the early wheat forage and rye forage. The rye forage did not significantly reduce corn silage yield. Unlike the winter annual plus corn double-crop systems, winter annual forages did not reduce the yield of double-cropped soybean (Table 3). There was no significant year by treatment interactions observed for all of the yield and quality parameters measured.

Table 3. Yield of corn grain, corn silage, and soybean double-cropped with the indicated winter annual forage. Means followed by the same letter are not significantly different at P = 0.05.

When corn or corn silage was double-cropped with the winter annual forage, the net value of the forage did not cover the subsequent loss in yield of the double-crop corn grain or corn silage (Table 4). However, when soybean was double-cropped with winter annual forage, the net return to land and management increased compared to soybean grown without the double-crop forage. The increase is primarily because the winter annual forage did not decrease the double-crop soybean yield. This indicates that the winter annual forage crop could be successfully positioned in a corn-soybean rotation if it was double-cropped with soybean. In dairy and livestock operations in the North Central states, a winter annual forage could be planted following the harvest of corn silage, which generally occurs in late summer or early fall.

Table 4. Net return to land and management. The returns reflect the value of the winter annual forage and the double-crop corn, corn silage, and soybean crop minus equipment and input costs for each crop system. Means followed by the same letter are not significantly different at P = 0.05.

Literature Cited

1. Andrews, D. J., and Kassam, A. H. 1976. The importance of multiple cropping in increasing world food supplies. Pages 1-10 in: Multiple Cropping. R. I. Papendick, ed. American Society of Agronomy Spec. Publ. 27. ASA, CSSA, SSSA, Madison, WI.

2. Bruckner, P. L., and Raymer, P. L. 1990. Factors influencing species and cultivar choice of small grains for winter forage. J. Prod. Agric. 3:349-355.

3. Carver, B. F., Krenzer, E. G., and Whitmore, W. E. 1991. Seasonal forage production and regrowth of hard and soft red winter wheat. Agron. J. 83:533-537.

4. 1997 Census of Agriculture: United States Summary And State Data. 1999. Geographic Area Series. USDA National Agricultural Statistics Service, AC97A-51, v.1, part 51.

5. Chan, L. M., Johnson, R. R., and Brown, C. M. 1980. Relay intercropping soybeans into winter wheat and spring oats. Agron. J. 72:35-39.

6. Dartt, B., and Schwab, G. D. 2001. Custom Work Rates in Michigan. Michigan State University, Agricultural Economics Staff Paper #2001-42.

7. Goering, H. K., and Van Soest, P. J. 1970. Forage Fiber Analysis: Apparatus, Reagents, Procedures, and Some Applications. USDA Agric. Handb. 379. U.S. Gov. Print. Office, Washington, DC.

8. Hach, C. C., Brayton, S. V., and Kopelove, A. B. 1985. A powerful Kjeldahl nitrogen method using peroxymonosulfuric acid. J. Agric. Food Chem. 33:1117-1123.

9. Hall, M. H. 1998. Harvest management effects on dry matter yield, forage quality, and economic return of four cool-season grasses. J. Prod. Agric. 11:252-255.

10. Jeffers, D. L., and Triplett, G. B., Jr. 1979. Management needed for relay intercropping soybeans and wheat. Ohio Rep. 58:67-69.

11. Kaplan, S. L., and Brinkman, M. A. 1984. Multiple cropping soybean with oats and barley. Agron. J. 76:851-854.

12. Moomaw, R. S., and Powell, T. A. 1990. Multiple cropping systems in small grains in Northeast Nebraska. J. Prod. Agric. 3:569-576.

13. Watkins, K. L. 1987. Total Nitrogen Determination of Various Sample Types: A Comparison of the Hach, Kjeltec, and Kjeldahl Methods. J. Assoc. Off. Anal. Chem. 70:3.

14. Wiersma, D. W., Carter, P. R., Albrecht, K. A., and Coors, J. G. 1993. Kernel milkline stage and corn forage yield, quality, and dry matter content. J. Prod. Agric. 6:94-99.