Ley In Rotation Research Articles

Combining organic fertilisation and perennial crops in the rotation enhances arthropod communities

Single and combined diversification practices in crop fields and their effects on arthropod predators, decomposers and herbivores have mainly been assessed in small plot and cage experiments. In particular, effects of diversification on arthropod predators and their food resources, such as soil fauna, weed seeds and herbivorous prey in entire crop fields across the growing season, remain unclear. We explored how organic fertilisers, with or without the legacy of perennial ley in the crop rotation, and mineral fertiliser without the legacy of perennial ley, affected below- and aboveground communities in 19 spring cereal crop fields. In each field, we determined the abundance of the soil mesofauna, communities of arthropod prey aboveground and of the predator guilds carabids, staphylinids and spiders. We sampled at three crop stages: tillering, heading and ripening. Weed cover and soil characteristics, such as carbon and nitrogen content, were assessed. For most soil mesofauna groups, the combination of organic fertiliser with the legacy of ley gave highest, organic fertiliser with annual crop rotations intermediate, and mineral fertiliser with annual crop rotations the lowest total abundance. Aboveground arthropod prey abundances were similar across treatments. The legacy of ley increased richness of all aboveground arthropod predators. Staphylinid communities’ abundance increased additively as diversification treatments were combined during tillering of the crop. Increasing organic amendments, alongside the reduced disturbances through inclusion of perennial ley in the rotation, led to more abundant communities below- and aboveground as well as more richness in aboveground predator communities.

The role of soil depth in the evaluation of management‐induced effects on soil organic matter

SummaryThe aim of the current survey was to determine the relevance of the subsoil in the assessment of management effects on soil organic matter (SOM) in arable farming. Data in this survey were provided by the organic arable long‐term field experiment Gladbacherhof (OAFEG). Three different ‘farming types’ were compared: mixed (MF), stockless with rotational ley (SFL) and stockless with cash crops (SFC). Each type had four different tillage treatments: full inversion (FIT), two‐layer plough (TLP), reduced inversion (RIT) and non‐inversion (NIT). The different mean masses of soil organic carbon (SOC) and soil total nitrogen (STN) at 0–30‐, 30–60‐, 60–90‐ and 0–90‐cm soil depths after three crop rotation cycles (17‐year observation period) were evaluated and considered as an indicator of SOM. ‘Farming types’ differ in their effect on SOC and STN mass of the topsoil layer (0–30 cm) in the order MF > SFL > SFC (P < 0.01). For the 0–90‐cm soil depth there were no differences between the treatments. Treatments with different tillage intensity did not show any effect on the contents of SOC or STN within the 0–30‐cm soil depth. However, within the 30–60‐cm depth full‐inversion tillage (FIT) was associated with larger amounts of SOC and STN than the reduced tillage intensity treatments TLP, RIT and NIT (P < 0.01). This situation even resulted in significantly larger SOC and STN masses under FIT (P < 0.05) over the whole soil profile under study (0–90 cm). Our results suggest that sampling depth should be extended to include the effects on the upper subsoil in assessment of the effects of arable management on soil organic matter.Highlights Role of subsoil in the assessment of management effects on soil organic matter in arable farming is rarely accounted for. We investigated SOC and STN contents below 0–30‐cm depth in a long‐term field experiment. Consideration of the subsoil had a marked effect on the differentiation of the treatments. Sampling depth should be extended to include effects of management on the upper subsoil in the assessment of soil organic matter.

Development of soil organic matter stocks under different farm types and tillage systems in the Organic Arable Farming Experiment Gladbacherhof

In 1998, the Organic Arable Farming Experiment Gladbacherhof (OAFEG) was started in order to explore the impact of different organic arable production systems (mixed farming, stockless farming with rotational ley, stockless cash crop farming) and of different tillage intensities (conventional plough as a full inversion tillage, two-layer plough, inversion tillage at reduced depth, non-inversion tillage) on sustainability parameters. In this article, we present results on the development of soil organic matter (SOM) levels. Starting with organic mixed farming with approximately 0.7 livestock units (LU) per ha cattle before set-up of the experiment, only the mixed farming system in the experiment was able to maintain SOM levels. The stockless system with ley maintained soil organic carbon (SOC), but lost soil total nitrogen (STN), and the stockless cash crop system had a significant SOM loss in the magnitude of 7.7 t SOM ha−1, or roughly 8.4% of the initial SOM mass. Reducing tillage intensity had no impact on SOM masses, but only on organic matter stratification in soils. We conclude that specialization of organic farms towards stockless arable crop production requires special attention on SOM reproduction to avoid detrimental effects. Further, reduced tillage intensity does not necessarily have a positive effect on SOM.

Soil structure, organic matter and earthworm activity in a comparison of cropping systems with contrasting tillage, rotations, fertilizer levels and manure use

In order to assess long-term effects on productivity, environmental impacts and soil fertility of contrasting farming practices, six cropping systems, ranging from conventional arable without livestock to organic mixed dairy farming with few arable crops, have been compared since 1989 on a loam soil. A decline in soil structure quality was found in a conventional arable system with annual ploughing with no rotational grass. This system had higher bulk density and mean aggregate size than other systems, and lower levels of plant available water and aggregate stability. Opposite trends were related to the proportion of grass leys in the other systems and to their levels of soil organic matter. The latter declined markedly over 15 years in the conventional arable system, and there were smaller declines in most other systems. In an arable system without ploughing, but with rotary tillage in spring, organic matter was maintained and high structural stability was found. This system had high bulk density, but the proportion of small aggregates equalled that found in systems with ley. There were overall increases in earthworm density (84%), earthworm biomass (80%) and the density of earthworm channels (132%) in the topsoil between 1994 and 2004. Most of these increases were found in systems with 1–3 years of ley in the 4-year rotation. Low values of all earthworm parameters, and only minor changes over the period studied, were found in two non-organic arable systems without ley, indicating high pressure on soil fauna. Lower earthworm activity was found in the non-organic arable system with reduced tillage as compared to the non-organic arable system with annual ploughing. Thus, 50% leys in the rotation appeared desirable for the maintenance of satisfactory soil structure and earthworm activity. Though the deterioration of soil structure in the conventional arable system was not extreme, as the soil was well structured initially, the results may have implications for the sustainability of stockless arable systems on soils with a less favourable initial structure.

Production, nitrogen and carbon balance of maize-based forage systems

Nitrogen (N) and carbon (C) surplus can be used as indicators of an agroecosystems’ ability to maintain soil fertility. Maize is the key crop of intensive forage systems in northern Italy, and large amounts of manure are often supplied to this crop. Different maize-based cropping systems and manure managements were compared in this paper. The following were assessed, using the results of an 11-year experiment: crop production and N uptakes; C and N surpluses; soil C and N contents. The treatments were maize for silage (Ms), maize for grain (Mg), double annual crop rotation maize–Italian ryegrass (Mr), and rotation maize–grass ley (Ml). Five fertilization management systems were adopted: 0N control, and bovine slurry and farmyard manure supplied at two levels, ranging from 215 to 385 kg ha −1 of total N. The dry-matter production of Mr was significantly higher than those of the other systems. The response of maize to fertilization was similar in all the cropping systems, except for Mr, for which the crop showed a high reactivity to N input at both fertilizer levels. Soil reserves were rapidly consumed in the unfertilized treatment of Mr, whereas the high productivity potential of this cropping system was exerted in fertilized plots. The introduction of a ley in rotation with maize reduced the system's DM production, due to the low yield potential of grass compared to that of maize, reduced the system response to fertilization, and diminished the exploitation of organic N at high fertilization rates. Cumulated N surplus caused an enrichment of the soil N pool size: 43% of excess N was retained by the soil. The relationship between the cumulated C surplus and the soil C pool size indicated that 26–27% was retained by the soil. Crop residues of the Mg system were less effective in building up the soil C pool than other C sources. Both slurry and farmyard manure exerted a positive effect on the soil C and N retention. When farmyard manure was used, 18% of C and 45% of surplus N were incorporated into the soil organic matter (SOM). Slurry also built up the SOM content, resulting in 9% of C and 24% of N surplus.