Organic Tillage Research Articles

Soil Bacteria Community Composition Indicating Soil Quality in Different Tillage Practices

Organic tillage practice of current study used fully cattle manure, while semi-organic tillage used cattle manure and 10% of synthetic fertilizers as transition to reduce chemical inputs in order to improve sustainable production and ecosystem health. Despite the important role of soil microbes in soil of agriculture, we still have limited understanding of the complex response of microbial composition to organic and semi-organic tillage practices. The aim of this work was to evaluate the impact of use of organic and semi-organic tillage practices on bacteria abundance, richness and functional diversity of microbial communities. Analysis of soil bacteria using nutrient agar by serial dilutions of soil suspension was performed to quantify bacteria abundance. They were further identified and categorized into IAA-producing bacteria and non IAA-producing bacteria groups in Tryptic Soy Agar (TSA). Bacteria abundance was significantly higher in semi-organic tillage than organic tillage. Even though bacteria richness did not show statistically significant, beneficial effect of organic tillage was reflected in higher bacteria richness in term of isolates. The assessment of their functional diversity on producing IAA hormone demonstrated higher IAA-producing bacteria than non IAA-producing bacteria in both tillage practices, indicating the availability of rich substrate through introduction of cattle manure improve soil quality and beneficial for soil bacteria. We observed that among all physicochemical properties, C-organic indicated highly significant, higher in organic tillage than semi-organic tillage. It has been proposed that the availability of organic carbon may favour bacteria as resource of energy. Keywords: Bacteria community composition; IAA-producing bacteria; Organic tillage; Semi-organic tillage

The effects of farming system and soil management on floristic diversity in sloping olive groves

Abstract The effects of the farming system (conventional-organic-abandoned) and soil management (native cover crop vs tillage) on vascular plant species were analyzed in sloping olive groves (>20%) in 20 different locations in Andalusia, SE Spain. The soil management techniques included Organic Tillage (OT), Organic Cover Crops (OC), Conventional Tillage (CT), Conventional Non-Tillage (CNT), Abandoned Cover Crops (AC) and Abandoned Woody (AW). Data for the vascular plant species were recorded through three line transects of 30 m with a bar perpendicularly touching every 1 m of the measuring tape. Environmental variables were also recorded at plot level to assess their influence. Dependent variables, such as species abundance, richness and diversity indexes were studied using univariate analysis (one-way ANOVA, Kruskal–Wallis test) while multivariate statistics (ANOSIM, SIMPER, DCA) were used for analyzing the data matrices. We found that the different combinations of farming system and soil management affect biological diversity in terms of individual abundance, plant cover, species richness and diversity, species and family composition. Life forms and species distribution patterns are also affected. The main environmental variables affecting the plant taxa were those related with soil and climate characteristics, slope, olive age and intensive land uses at landscape level, including the percentage of artificial surfaces. The lowest levels of biodiversity (e.g., species richness) were found in the tilled olive groves (CT = 8.1 sp. ± 2.2, OT = 10.0 sp. ± 5.4). Surprisingly, the organic tilled groves (OT) were very poor in species compared to those with native plant cover (OC = 27.9 sp. ± 3.0). The latter, however, showed similar species richness to the abandoned olive groves (AC = 21.2 sp. ± 3.7, AW = 27.2 sp. ± 3.0). Possible solutions for increasingly uncompetitive sloping olive groves include conversion to organic with native plant cover or abandonment for rewilding.

Varying tillage promotes weed diversity, while a perennial alfalfa–grass mixture promotes weed control in an organic tillage system experiment in Germany

AbstractIn organic farming the control of perennial weed species, in particular Cirsium arvense, can be a major concern for farmers, especially if there is no regulation through perennial forage production. To test whether the stubble cleaner (SC), an enhanced skim plow (PL), is as effective in the control of C. arvense and other weeds as conventional ploughing and perennial forage production, an organic field experiment was established. Three different tillage/crop rotation systems were compared: an SC system and a PL system, both in a cereal-based crop rotation and an additional PL system in a crop rotation that included a perennial alfalfa–grass mixture (PLALF). In the SC system, tillage was carried out solely with the SC, while in the PL and PLALF systems, ploughing was alternated with chiseling. In the fifth year, each main plot was divided into subplots, and seven different cover crop treatments were integrated into each of the three systems. The effects of the three systems and the cover crop treatments on weed cover and density, weed biomass, and weed diversity in the sixth and seventh year of the experiment are the subjects of this paper. The choice of cover crop species was of minor importance for weed control. The PLALF system was generally more effective in controlling C. arvense than the PL and SC systems. No significant differences between the PL and SC systems regarding the control of C. arvense could be identified in four of five assessments. The SC system had significantly higher total weed density than the PLALF and PL systems in both years. However, the differences in weed emergence between the PL and SC systems diminished until the assessment of weed cover and biomass in the main crops, when no significant differences between these two systems (2012) or no differences at all (2013) could be identified. Species richness was not significantly influenced by the tillage/crop rotation system in both years. Evenness and Shannon–Wiener index were significantly higher in the PLALF and PL systems than in the SC system on most assessment dates in 2012. In 2013 there was no clear trend regarding evenness and Shannon-Wiener index probably due to a hoeing operation.. In conclusion, for weed control, the choice of crop rotation was more important than the choice of tillage method, while for the diversity of the weed community, the choice of tillage method was more important than the crop rotation.

Qualidade do solo cultivado com morangueiro sob manejo convencional e orgânico

A manutenção das funções do solo nos agroecossistemas encontra-se entre os principais desafios da comunidade científica, na atualidade. Assim, este estudo objetivou avaliar indicadores físicos, químicos e biológicos de qualidade do solo, em três unidades de produção comercial de morango, em Brazlândia (DF), sendo duas sob sistema de produção convencional (Conv1 e Conv2) e uma sob sistema orgânico (Org). O Conv1 é caracterizado pelo cultivo de morango em área que esteve ocupada por 12 anos com pastagem (Brachiaria spp.), sem controle de lotação e sem adubação; o Conv2 pelo cultivo do morango em sucessão/rotação com outras espécies olerícolas; e o Org ocorreu após a adubação verde com o consórcio de milho e mamona. Os atributos indicadores de qualidade do solo avaliados foram: densidade de solo, estabilidade de agregados, matéria orgânica, capacidade de troca catiônica (CTC), condutividade elétrica, β-glicosidase e fosfatase ácida. Os valores observados para os indicadores físicos foram, de maneira geral, considerados sustentáveis, para latossolos do Cerrado. Os teores de matéria orgânica mostraram-se similares em todos os sistemas e a CTC foi superior ou próxima ao limite crítico considerado sustentável. Em função da elevada aplicação de fertilizantes, a maior condutividade elétrica foi registrada para o Conv2, mas não houve efeito deletério sobre a produtividade. As atividades das enzimas β-glicosidase e fosfatase ácida indicaram boa qualidade biológica do solo, em todas as unidades produtivas de morango avaliadas.

Stratification ratio of soil organic C, N and C:N in Mediterranean evergreen oak woodland with conventional and organic tillage

The Mediterranean evergreen oak woodland (MEOW-dehesa) is the most widespread agroforestry system in Mediterranean Europe and integrates forestry, agricultural and livestock practices. The MEOW-dehesa is a grazing system with evergreen Quercus ilex spp. ballota. It is characterized by the conservation of forest oaks (Quercus spp.) and provides environmental benefits such as carbon capture and storage in soils.The effect of conventional tillage (CT) and organic tillage (OT) on the distribution of soil organic carbon (SOC), total nitrogen (TN) and C:N ratios has not been well documented in the MEOW-dehesa. The objective of this paper is to study these parameters in the MEOW-dehesa in two soil types (Leptosols and Cambisols) and two management systems, OT for 20 years and CT. The stratification ratio (SR) of SOC, TN and C:N ratio is also evaluated. An analysis is performed on 85 soil profiles over the 2005–2009 period in southern Spain.The SR of SOC in Cambisols was greater under OT than CT, ranging from 1.25 to 1.42 and from 1.3 to 1.6 under CT and OT, respectively. The SR of TN for 0–20.9cm, 20.9–55.5cm and 55.5–102.1cm depth was greater under OT than under CT. The OT also increased the stratification of the C:N ratio compared to CT.