Soil Health Indicators during Transition from Row Crops to Grass–Legume Sod

Abstract

Core Ideas Transition from organic row crop to 3‐yr sod led to significant changes in surface soil health. Changes in soil chemistry were generally subject to a manure × transition time interaction. Manure plus sod are required to increase organic matter in deficient soils. Soil quality and/or health changes with grass sod insertion in a rotation. Grass–Legume sod inclusion in row crop rotations changes soil health. The transition to a 3‐yr orchardgrass (Dactylis glomerata L.) and red clover (Trifolium pratense L.) sod was examined in an existing 7‐yr organic rotation with four row crop years: corn (Zea mays L.), soybean (Glycine max L. Merr.), wheat (Triticum aestivum L.), and kale with cowpea (Brassica oleracea and Vigna unguiculata). The study objectives were to determine changes in soil physical health indicators, nutrient stratification, and grass and/or legume biomass during the 3‐yr sod growth period, at two composted beef manure rates applied twice in the rotation, prior to corn or wheat establishment. Soil properties were determined in 2013 and 2014 on a four (annual rotation components: TY0, kale and cowpea going to grass–legume sod; TY1, first sod year; TY2, second sod year; TY3, third sod year) by two (non‐manured and manured) factorial treatment subset. Sod biomass was determined in 2013 and 2014 on the three (TY1, TY2, and TY3) by two (non‐manured and manured) factorial treatment subset. Surface (0–5 cm) soil health parameters increased between TY0 and TY3, including bulk density (non‐manured 1.21 ± 0.08 to 1.29 ± 0.06; manured 1.10 ± 0.07 to 1.18 ± 0.09 kg m–3); wet aggregate geometric mean diameter (non‐manured 3.68 ± 2.28 to 4.32 ± 2.83; manured 3.99 ± 1.39 to 5.27 ± 0.45 mm); organic matter (non‐manured 36.1 ± 6.0 to 39.4 ± 5.1; manured 49.3 ± 9.1 to 60.7 ± 9.9 g kg–1). Nutrient (P, K, Ca, Mg and Zn) stratification was observed. There was a transition year × manure interaction where manure increased the rate of soil parameter change. Both manure addition and sod insertion improved aggregate stability, organic matter, total N and bioavailable nutrients.

Soil Health Assessment in Reclaimed Mine Soils

“…The measurements of K, Ca, Mg, and Zn were comparable to those found in an agricultural soil at the organic farm in Monongalia Co., WV (Pena-Yewtukhiw et al, 2017). The measured P in this study was found to be lower than the P in the literature in both the agricultural system and mine soils (Roberts et al, 1988;Bendfeldt et al, 2001;Pena-Yewtukhiw et al, 2017). The measured K was similar to those found by Roberts et al (1988) and Bendfeldt et al (2001).…”

Rapid response of nitrogen cycling gene transcription to labile carbon amendments in a soil microbial community

“…The mechanisms regulating N uptake in response to C have been extensively studied in vitro (8,25). The complex regulatory network includes a specialized sigma factor (σ 54 ; rpoN), . CC-BY 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.…”

Crop rotations that integrate pasture are less vulnerable to nitrogen leaching due to changes in microbial community composition and reduced nitrification

“…This suggests that pasture enhances the organic matter inputs to the soil through below ground biomass or root exudation. A separate study of the soils from the OCLF experiment showed that SOM increased from the beginning to the end of the three-year period spent in pasture (Pena et al 2017). A study of root biomass growth in forage crops in eastern Canada found that root biomass doubled from the first to the second year of growth of perennial grasses and legumes, and that these forage crops had lower shoot to root ratios than annual crops (Bolinder et al 2002).…”

“…The combination of reduced ammonium availability and lower abundance of AOO contributes to greater potential for retention of nitrogen from organic sources. Additionally, pasture can develop soil structure and increase SOM, leading to improved stability and water infiltration and retention (Pena et al 2017). Implementation of practices such as pasture integrated crop rotation can help managers to maintain yields while preserving soil health and preventing environmental damage.…”

“…Pasture integration into crop rotations may introduce carbon-rich substrates for microbial decomposition. Perennial pasture species allocate half or more of their biomass below ground (Boot et al 1990) and can increase soil organic carbon contents over time (McLauchlan et al 2006), including increases in organic matter in incorporation into crop rotation (Pena et al 2017). Consequently, this management practice may stimulate nitrogen immobilization by soil heterotrophs, especially when pasture is tilled into the soil prior to crop production, potentially limiting losses from nitrogen fertilizer.…”