Long‐term organic management combined with conservation tillage enhanced soil organic carbon accumulation and aggregation

Abstract

Successful synergy between organic management and conservation tillage could provide the best agroecological benefits by minimizing the negative effects of both synthetic chemicals and intensive tillage on soils. We studied the long-term impacts of conventional and organic crop management under different tillage regimes on soil organic C (SOC) and soil aggregation, leveraging Rodale Institute's long-term Farming Systems Trial. The experiment was initiated in 1981 with three cropping systems under intensive tillage management: (a) conventional (3-yr rotation of corncorn-soybean) with synthetic fertilizer application, (b) organic-legume (4-yr rotation of corn-oats-soybean/wheat-wheat) organic system with legume as sole N source, and (c) organic-manure (8-yr rotation of soybean/wheat-wheat/hay-hay-hay-corn silage/wheat-wheat-corn-oats) organic system with composted manure and legumes as N sources. There were eight replications for each of these cropping systems when the trial was initiated in 1981. In 2008, four replicates of each cropping system treatment were placed under conservation tillage management. Soils were collected from 0 to 10-, 10 to 20-, and 20 to 30-cm depths in 2018 and measured for total SOC, active SOC fractions (microbial biomass C, water extractable C, permanganate-oxidizable C), aggregate size distribution, and wet aggregate stability. Overall, total and active SOC increased by 16-132% under organic management compared with conventional management and the increase was more pronounced under organic-manure treatment than organic-legume treatment. Results also showed that 10 yr of tillage treatments did not influence active and total SOC concentrations, but influenced dry aggregate size distribution and wet aggregate stability. This study suggests that in longterm organic cropping systems, incorporated composted manure and perennial hay vs. legumes alone accumulated the greatest amount of SOC compared with conventional systems. Conservation tillage in organic systems improved aggregation; however, beyond 10 yr, it is necessary to reflect tillage effects on SOC.

Response of bacterial community structure and diversity to different fertilization regimes in the rhizosphere soil of Camellia oleifera

“…The nutrient composition of commercially available organic and inorganic mixed fertilizers is comprehensive and balanced, which is also conducive to the growth and reproduction of microbial colonies (Moritsuka et al, 2001). Continuous fertilization conforms to the nutrient requirements of plants and microbial communities at different growth stages (Littrell et al, 2021). This research also revealed that the organic fertilizer could slowly reduce the content of sand and increase the proportion of silt, which probably resulted from the ability of soil microorganisms to dissolve the insoluble fine sand.…”

The reflection of principles and values in worldwide organic agricultural research viewed through a crop diversification lens. A bibliometric review

“…'Soil management' and 'Weed control' (topics 5 and 3) were also jointly addressed in some articles, for instance on the design of organic cropping systems with conservation tillage or no-tillage, in which synergies between reduced weed infestation and maintenance of long-term fertility of the system for productivity are sought (Peigné et al 2007;Halde et al 2015;Hashimi et al 2019;Littrell et al 2021). The proximity between these two topics was also reflected in the large number of alternative products tested to control weeds while acting assoil amendments, such as tea compost (Vail et al 2020), green manure (Carlesi et al 2020) and dead mulches (Sihi et al 2017;Ginakes et al 2020), and additional and novel crops in the rotations (e.g.…”