Profitability of Various Corn, Soybean, Wheat, and Alfalfa Cropping Systems

Producers are frequently most interested in economic comparisons of various cropping systems. We compared continuous corn (Zea mays L.) and continuous soybean [Glycine max (L.) Merr.] with 2-, 3-, and 5-year rotations, the latter two including wheat (Triticum aestivum L.) and alfalfa (Medicago sativa L.), using either chisel plow or no-tillage practices. Crop yield and returns to land and management were evaluated. Yields for continuous corn (C-C-C) were not different from those in rotation [corn-soybean (C-S), soybean-wheat/soybeancorn (S-W/S-C), or corn-soybean-alfalfa-alfalfa-alfalfa (C-S-A-A-A)] for either tillage practice, but rotated corn had lower nitrogen (N) inputs. Soybean yield in the 5-year rotation was greater than for continuous soybean (S-S-S) in 2001 for both tillage practices, but in 2000, a tillage by rotation interaction resulted from severe crusting in S-S-S that reduced stand density and lowered yield for the chisel plow treatment. Wheat and alfalfa yields were not affected by tillage practice. Using average annual crop prices, the 5-year rotation generated returns that were 100 and 158% higher than for C-S using either no-tillage or chisel practices. This study confirms that producers who incorporate alfalfa into their crop rotations can significantly increase returns to land and management. However, returns for the rotation including alfalfa are more realistic where a viable forage market exists. Introduction Crop rotation has been shown to increase corn yield 5 to 30% and soybean yield from 8 to 16% compared to continuous production of either crop (3,4,9,11,12,16,20). It has also been shown to improve N use efficiency by reducing requirements for external input of fertilizer N. Compared to C-C-C, Kanwar et al. (7) reduced fertilizer N inputs 17% for a C-S rotation and reduced NO3-N leaching loss through subsurface tile lines. Bruulsema and Christie (1) found that single-year plowdown of alfalfa or red clover (Trifolium pratense L.) was equivalent to yields obtained from applying 80 to 111 lb/acre of fertilizer N. Fox and Piekielek (5) extended the evaluation period to three years of alfalfa managed as hay and reported that there was no significant grain yield response to fertilizer N for first-year corn. One result of increased crop yield and improved N use efficiency with crop rotation may be more favorable economics or net return to producers. For example, when averaged for moldboard plow and chisel tillage systems in an Iowa study, Chase and Duffy (2) reported a return to land, labor, and management for continuous corn of $142/acre compared to $147/acre for corn rotated with soybean. The rotated corn also required 17% less N fertilizer (150 vs. 180 lb/acre). In New York, Singer and Cox (17) reported greater net return Crop Management 30 January 2003 for a C-S rotation ($101/acre) than for C-C-C ($78/acre) or a three year soybean-wheat/red clover-corn rotation ($54/acre) with reduced inputs. Katsvairo and Cox (8) calculated that a C-S rotation with reduced inputs returned $40/acre compared to $5/acre in C-C-C with full inputs and chisel tillage. Similarly, Hesterman et al. (6) compared the profitability of alfalfa-corn (A-C), C-C-C, and C-S rotations and concluded that an A-C rotation provided the greatest returns. They also concluded that to amortize alfalfa establishment costs over a longer period of time, the crop should be managed as forage rather than a green manure. Although the net returns are often the most requested piece of data when crop rotation studies are reported to producers, very few experiments have provided that information, especially those that include both forage and grain crops as well as tillage treatments. Our objective is to examine both crop yield and returns to land and management for monocultures (C-C-C and S-S-S) and rotations that include wheat and alfalfa. Comparisons are provided for both chisel-plow and no-tillage practices. Materials and Methods A tillage by crop rotation field study was established in the fall of 1998 on a Quakertown silt loam (fine-loamy, mixed, mesic Typic Hapludults) at the Rutgers University Snyder Research and Extension Farm near Pittstown, NJ (40o30’N, 75o00’W). The study was a randomized complete block design with a split plot arrangement of treatments that were replicated four times. The main plots (240 ft by 50 ft) were either chisel plowed or managed using no-tillage practices, although primary tillage was used only prior to corn or for full-season soybean production. Wheat and alfalfa seedbed preparation in the chisel plots was limited to a single tandem disking followed by one or two passes with a field cultivator. Double-crop soybean was planted no-till for both treatments to expedite planting and because it is the most common practice for double-crop systems. All field operations for tillage and crop rotation treatments are listed in Table 1. Crop Management 30 January 2003 Table 1. Field operations utilized for comparing chisel plow and no-tillage treatments for various crop rotations on a silt loam soil in New Jersey. a Applied lime to all plots in 2001. b No spraying was done following planting in 2001. c Alfalfa was fertilized twice in 2001. d Chisel plow, tandem disk, and field cultivator operations were not conducted. No-till planting (with and without fertilizer) replaced conventional planting (with and without fertilizer). All other field operations remained the same as the chisel plow system. e Corn, soybean, and wheat were harvested with a combine. To estimate production costs, it was assumed that wheat straw was raked and baled and alfalfa was mowed, then raked and baled twice in the establishment year and four times in the 2nd and 3rd years, while the last cutting of alfalfa in each year was chopped as haylage. All phases of each crop rotation were imposed on subplots (20 ft by 50 ft) when the study was initiated, thus creating C-C-C, S-S-S, C-S, C-S-W/S, and CS-A-A-A treatments. The first two years (1998 and 1999) were considered establishment years, with soybean being planted late in 1998 to simulate typical double-crop planting dates. This study focused on the corn, soybean, wheat, and alfalfa yields during the 3rd (2000) and 4th (2001) years. Therefore, for corn we evaluated C-C-C, C-S-C, S-W/S-C, and A-A-C treatments (bold letters) in 2000 Field Operation Continuous corn or corn-soybean Corn after alfalfa Soybean Soybean after Wheat Wheat 1st year alfalfa 2nd & 3rd year alfalfa