Soil Organic Carbon Sequestration Rates under Crop Sequence Diversity, Bio‐Covers, and No‐Tillage

Abstract

Climate change may be mitigated through soil organic C (SOC) storage under no‐tillage; however, crop management influences on SOC are not well defined in all systems. Our objective was to compare long‐term C fluxes under two no‐tillage sites at Research and Education Centers in Milan (RECM) on Oxyaquic Fragiudalfs and at Middle Tennessee (MTREC) on a Typic Paleudalf in a split‐block design with four replications. The whole‐block was cropping sequences of corn (Zea mays L.), soybeans [Glycine max (L.) Merr.], and cotton (Gossypium hirsutum L.) with split‐block bio‐cover treatments of winter wheat (Triticum aestivum L.), hairy vetch [Vicia villosa Roth subsp. villosa], poultry litter, and a fallow control. The same sequences were performed at MTREC without cotton. Soil C flux was calculated at surfaces (0–5 cm) and subsurfaces (5–15 cm) during Year 0, 2, 4, and 8. During the first 2 yr, C losses occurred in all treatments and locations (1.40 and 1.20 Mg ha−1 at RECM and MTREC, respectively), with stabilization initiating by Year 4. By Year 8, sequences with high frequencies of soybean and greater temporal complexity gained more surface SOC. Poultry litter bio‐covers gained more surface SOC compared to wheat, vetch, and fallow bio‐covers (P < 0.05). After 8 yr, surface SOC surpassed initial levels (9.20 and 8.79 Mg ha−1), with mean gains of 1.33 and 1.16 Mg C ha−1 at RECM and MTREC, respectively. Losses occurred in subsoils at MTREC and RECM, but by Year 8 several treatments had recovered to near baseline levels. Results suggest surface C storage may be enhanced by crop sequence diversity combined with poultry litter bio‐covers in no‐till systems, whereas subsurface levels may require more time.

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

“…Insect populations may also be reduced, predominately because cover crops provide habitat for beneficial insects that regulate population levels (Creamer and Baldwin, 1999;Tillman et al, 2004). Incorporating cover crops during the offseason, as well as including greater temporal cropping diversity also reduces erosion and increases soil organic carbon (SOC), which has been reported previously by authors (Ashworth et al, 2014).…”

“…Previous research has also shown that poultry litter applications can serve to increase soybean yield (Adeli et al, 2005). This could also be due to the stimulation of SOC formation under greater flushes of N and P (Table 2) which are required for microbial biomass assimilation and correlated to microbial biomass C (DeForest and Scott, 2010;Ashworth et al, 2014). Similarly, an 8-yr study conducted in Illinois found no soybean yield benefits from the inclusion of cover crops into cropping rotations (Olson et al, 2010).…”

“…Greater photosynthetic and microbial-based C additions, more complex crop rotations, and poultry litter additions have been implicated in increasing soil C accumulation (Ogle et al, 2005;Ashworth et al, 2014). Furthermore, crop rotation can also influence the amount and quality of soil organic N, since Drinkwater et al (1998) suggest that lower C/N residues combined with greater temporal crop diversity, especially with legumes, increases C retention in soils.…”

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

“…Poultry litter has proven to increase fertility and meet crop N requirements (Endale et al, 2004; Tewolde et al, 2010). In addition to direct crop benefits from soil fertility, ancillary benefits include liming of acidic soils, as well as organic matter additions (Ashworth et al, 2014). Poultry litter applications and subsequent green manure (e.g., winter weed growth due to a flush of P and N) can alter soil chemical and subsequent biological profiles over time, although the extent of this is largely unknown.…”

Soil carbon and nitrogen stocks and physical properties under no‐till and conventional tillage cotton‐based systems in the Brazilian Cerrado

“…After 9 years of cultivation, This effect is mainly attributed to the conservation of soil structure promoted by NT-protected SOM against rapid microbial decomposition, because interaction of SOM and structure protects SOM from oxidation, which maximize recalcitrant C formation and increase stable C fractions (Blanco-Canqui & Lal, 2004). Additionally, crop rotation also contributes to enhance C sequestration under NT compared with CT, due to more diverse substrate and exudates in aboveground and belowground residues (Ashworth et al, 2014;Franzluebbers, Stuedemann, Schomberg, & Wilkinson, 2000).…”