Impact of Crop Rotations and Soil Amendments on Long‐Term No‐Tilled Soybean Yield

Abstract

Continuous cropping systems without cover crops are perceived as unsustainable for long-term yield and soil health. To test this, cropping sequence and cover crop eff ects on soybean (Glycine max L.) yield were assessed. Main eff ects were 10 sequences of soybean, corn (Zea mays L.), and cotton (Gossypium hirsutum L.) grown on a Loring silt loam at the Research and Education Center at Milan (RECM), TN, and six cropping sequences of corn and soybean on a Maury silt loam at the Middle Tennessee Research and Education Center (MTREC), Spring Hill, TN. Sequences were repeated in 4-yr Phases (i.e., I, II, and III) from 2002 to 2013. Split-block treatments consisted of hairy vetch (Vicia villosa L.), Austrian winter pea (Pisum sativum L. sativum var. arvense), wheat (Triticum aestivum L.), poultry litter, and a fallow control. Continuous soybean yield was equivalent to all rotations (2.6 and 2.7 Mg ha -1 , respectively; P = 0.23), however, yield varied per phase (P < 0.001). Specifi cally, soybean yield in soybean-soybean-corn-cotton during Phase II and corncorn-soybean-corn during Phase I (4.2 and 4.1 Mg ha -1 , respectively) exceeded continuous systems during Phases II and III (P < 0.05). Poultry litter increased yield 11% across locations and years compared to wheat cover crops (P < 0.05). Incorporating corn once within a Phase increased yield 8% relative to continuous soybean, whereas cotton (once or twice) within a rotation had no eff ect. Consequently, including corn once within a 4-yr rotation and poultry litter improved soybean yields, albeit no mono-cropping yield penalties occurred long-term. Core Ideas• Poultry litter increased yields by 11% across locations and years when compared to wheat cover crops.• Yields in soybean-soybean-corn-cotton rotations during Phase II and corn-corn-soybean-corn during Phase I were greatest.• Incorporating corn once within a 4-yr cropping cycle resulted in 8% greater yields than continuous soybean.• Continuous cropping systems without cover crops are oft en perceived as unsustainable for long-term yields and soil health.

Crop Rotations and Poultry Litter Affect Dynamic Soil Chemical Properties and Soil Biota Long Term

“…At RECM, poultry litter was the greatest positive driver for earthworm abundance and composition, as was the corn–soybean rotation. Previous research on the same plot area noted significantly reduced earthworm abundance under continuous cotton, likely owing to the pesticide‐intensive rotation of cotton (Ashworth et al, 2017a). Therefore, as noted above, more SOC was stored in the upper profile of cotton sequences due to the dominant role that earthworms play in breaking down recalcitrant residues.…”

“…Similarly, the soybean–soybean–corn–soybean rotation had the lowest K levels (98.8 kg ha −1 ). In general, soybean produces about one‐third the amount of residue of corn, but about twice as much K is removed in the grain (Wilhelm et al, 1986; Ashworth et al, 2017a). The continuous corn and the cotton–corn rotation resulted in greater K, N, and C (7.9 Mg ha −1 ) levels in the upper 15 cm than the soybean–soybean–corn–soybean rotation ( P < 0.05, Fig.…”

“…Soils were collected between crop rows from each plot center with a shovel and were hand sorted by species present ( Diplocardia caroliniana Eisen, Lumbricus rubellus Hoffmeister, and Amyntha spp.) to determine abundance per Ashworth et al (2017a).…”

“…Finally, nonparametric multidimensional scaling ordination of Bray–Curtis dissimilarities was performed using PRIMER 7.0.13 software to visualize the relationships between microbial community structures and dynamic soil properties. Analysis was performed as described in Ashworth et al (2017); briefly, operational taxonomic unit relative abundances were normalized by total and square root transformed prior to calculation of the distance matrix. The chemical properties and earthworm abundances were related to microbial community structure using Pearson correlations.…”

In-Field Habitat Management to Optimize Pest Control of Novel Soil Communities in Agroecosystems

“…Tillage has been used for centuries to control pests, including weeds, insects, and other invertebrates, such as slugs, but regularly disrupting soil decreases its quality and leaves it susceptible to erosion [ 54 , 55 , 56 ]. Crop rotation is a stalwart of IPM, and remains a reliable approach for disrupting pest lifecycles [ 56 , 57 , 58 , 59 ]. Moreover, there is strong evidence that more diverse rotations have fewer pest populations [ 58 , 60 ].…”