Pleveli kot bioindikatorji: vzorčenje in uporaba podatkov

Članek opisuje uporabo plevelnih vrst kot indikator-jev stanja tal, ki je povezano ali z lastnostmi tal (kot sta pH ali tekstura tal) ali z gospodarjenjem s tlemi (zastajanje vode v tleh, premalo ali preveč hranil, zbitost). Poudariti je treba, da: (i) Tovrstna analiza ne zagotavlja vedno doslednih rezultatov. Odnos med različnimi plevelnimi vrstami in stanjem tal namreč ni vedno jasno začrtan. (ii) Za izvajanje te metode vzorčenja je potrebno nekaj osnovnega botaničnega znanja za identifikacijo plevelov

Las malas hierbas como bioindicadores del suelo: Cómo muestrear y usar los datos

Esta ficha técnica describe cómo las especies de malas hierbas pueden ser utilizadas como bioindicadores de las condiciones del suelo, relacionándolas con las características del suelo (como pH o textura)y al manejo del suelo (como el uso del agua, falta o exceso de nutrientes o compactación. Debe destacarse que (i) este tipo de análisis no siempre proporciona resultados consistentes, porque la relación entre las malas hierbas y las condiciones del suelo no siempre es clara y que (ii) la metodología de muestreo sugerida requiere conocimientos botánicos básicos para la identificación de especies. English version available at https://orgprints.org/31696

Weeds as soil bioindicators: How to sample and use data

This technical note shows how weed species can be used as indicators of soil conditions that are either linked to soil characteristics (such as soil pH or texture) or to soil management (such as water logging, lack or excess of nutrients, compaction). It should be stressed that (i) this kind of analysis does not always provide consistent results, because the relationship between weed species and soil conditions is not always clear cut and that (ii) the suggested sampling methodology requires some basic botanical skills for weed identification

Hairy vetch cover crop affects weed diversity and composition in no-till sunflower

Vicia villosa Roth, or hairy vetch, is one of the most productive cover crops (CC) in Mediterranean dry areas, with an interesting potential as dead mulch in no-tillage cropping systems. In low-input cropping systems, mechanical termination of hairy vetch could replace a glyphosate application to control weeds. Mechanical termination (e.g. with a roller crimper) of hairy vetch is ineffective until the late growing stages of vetch, leading to delayed sowing and yield reduction in the following crop. To find the best compromise in timing between effective termination of vetch and reasonable yield of no-till sunflower, an on-farm experiment was carried out in Pisa (Italy) in 2012/13 and 2013/14 to compare three termination techniques (roller crimper with no, half and full dose of glyphosate) and three termination dates (before flowering, beginning of flowering, 70% of flowering of vetch). Data on weed biomass, species density and soil cover were collected at CC termination and during sunflower growth. Weed diversity and composition were analyzed through ANOVA, PERMANOVA and NMDS

Long term effects of cover crops on weeds in Mediterranean low input arable management systems

The introduction of cover crops (CC) in crop rotations is a key tool to control weed and ameliorate soil conditions in low input arable systems. In 1992 a long term experiment (LTE) was set up at Centre for Agri-environmental Research “E. Avanzi (CIRAA), University of Pisa to determine the combined effect of tillage intensity, nitrogen fertilization levels and CC types on soil quality, crop yield and weed communities. The LTE is based on 4-year crop rotation (maize, durum wheat, sunflower, durum wheat) with cover crops grown twice, in between wheat and summer crops. Two tillage systems were compared: i) a conventional system (CS), with annual ploughing (30 cm depth); ii) a low input system (LIS), with chiseling (30 cm depth) for summer crops and no till for wheat. In both systems cover types were: control; Brassica juncea L.;Trifolium squarrosum L.; and Vicia villosa Roth.). Four Nitrogen levels (from 0 to a maximum rate, varying across crop type) were applied. The experiment was replicated in 4 blocks for a total of 128 plots (21 x 11 m). Weed and CC above-ground biomass were assessed at CC termination, while weed species cover and total biomass were assessed at harvest. Data collected in CC (2011, 2014), sunflower (2012), durum wheat (2012) were used to calculate species richness, weed community diversity indices (Shannon’s H’ and inverse Simpson index) and Pielou equitability. Weed biomass and cover were analyzed by split-split plot ANOVA. Weed community composition was analyzed by a permutational multivariate analysis of variance based on Bray Curtis dissimilarity and Non-metric Multidimensional Scaling

Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

No-tillage, N fertilization and cover crops are known to play an important role in conserving or increasing SOC and STN but the effects of their interactions are less known. In order to evaluate the single and combined effects of these techniques on SOC and STN content under Mediterranean climate, a long term experiment started in 1993 on a loam soil (Typic Xerofluvent) in Central Italy. The experimental variants are: conventional tillage (CT) and no-tillage (NT), four N fertilization rates (N0, N1, N2 and N3) and four soil cover crop (CC) types (C - no cover crop; NL - non-legume CC; LNL - low nitrogen supply legume CC, and HNL - high nitrogen supply legume CC).The nitrogen fertilization rates (N0, N1, N2 and N3) were: 0, 100, 200, 300kgNha-1 for maize (Zea mays, L.); 0, 60, 120,180kgNa-1 for durum wheat (Triticum durum Desf.); 0, 50, 100, 150kgNha-1 for sunflower (Helianthus annuus L.).From 1993 to 2008, under the NT system the SOC and STN content in the top 30cm soil depth increased by 0.61 and 0.04Mgha-1year-1 respectively. In the same period, the SOC and STN content under the CT system decreased by a rate of 0.06 and 0.04Mgha-1year-1 respectively. During the experimental period, N1, N2 and N3 increased the SOC content in the 0-30cm soil layer at a rate of 0.14, 0.45 and 0.49Mgha-1year-1. Only the higher N fertilization levels (N2 and N3) increased STN content, at a rate of 0.03 and 0.05Mgha-1year-1.NL, LNL and HNL cover crops increased SOC content by 0.17, 0.41 and 0.43MgCha-1year-1 and -0.01, +0.01 and +0.02MgNha-1year-1.Significant interactions among treatments were evident only in the case of the N fertilization by tillage system interaction on SOC and STN concentration in the 0-10. cm soil depth in 2008.The observed SOC and STN variations were correlated to C returned to the soil as crop residues, aboveground cover crop biomass and weeds (C input).We conclude that, under our Mediterranean climate, it is easier to conserve or increase SOC and STN by adopting NT than CT. To reach this objective, the CT system requires higher N fertilization rates and introduction of highly productive cover crops

Experiences from a winter school on landscape agronomy: Stakes, difficulties, perspectives

International audienceIn the latest fifteen years, agronomic research has shown a growing interest for studies which link farm or field scale to landscape scale. Thus, agronomy is called to renew its research questions and methodologies, and as well its educational programmes. In this context, some French and Italian researchers interested in these topics, coming from different scientific fields but sharing interests on landscape scale issues in research and higher education, decided to join their efforts around a common one-week educational programme on Landscape Agronomy for undergraduate and PhD students. Their aim has been to develop a new form of knowledge transfer and application on Landscape Agronomy approaches to students of SSSA-Pisa (IT) and of the PhD School of ABIES-AgroParisTech-Paris (FR). The educational programme consisted of three phases : 1) some theoretical contributions supported by presentations on : issues regarding agriculture and farming practices at landscape level, main approaches on environmental functions of agriculture, changes in farmers practices driven by environmental questions,spatial organization of agricultural activities, role of farming in ecological dynamics, identification of complementarities among agro-environmental functions, environmental impacts of cropping systems,biodiversity influence on agro-ecosystem functions and vice-versa ; 2) two case-studies: a macro level one(at landscape scale) to analyse the role of agriculture on landscape dynamics, and a micro level one (at farm scale) to analyse farming practices and their environmental impacts ; 3) a final evaluation of the educational programme based on : contents of oral presentations on fieldwork results, global evaluation of the educational programme contents by all the participants, each individual ex-post analysis of fieldwork results. The evaluation of the students and teachers underlines benefits, requests and perspectives for education in landscape agronomy. Furthermore, this experience stimulated a collective conceptual and methodological debate that confirmed the necessity to favour and organise experience exchanges on researching and learning in landscape agronomy

EFFECT OF CONSERVATION PRACTICES ON FUNCTIONAL DIVERSITY AND ASSEMBLY OF WEED COMMUNITIES: A DATABASE OF FUNCTIONAL TRAITS

The incorporation of conservation agriculture techniques (e.g. reduced tillage and green manures) in organic farming systems brings many benefits to the environment and reduces energy use (Holland, 2004). One of the main drawbacks of the use of reduced tillage is the potential increase in weed infestation and shifts in the weed community composition, sometimes to the benefit of more difficult-to-control species (Bàrberi, 2002; Peigné et al., 2007; Sans et al., 2011). However, weeds have an important role in maintaining farmland functional biodiversity (Bàrberi et al, 2010; Caballero et al., 2010), and this should be balanced with their potential negative impact on crop yield and quality. Within the frame of the European project “Reduced tillage and green manures for sustainable cropping systems” (TILMAN-ORG), in 2012 we started a study with the aim of evaluating the effects of conservation agricultural methods on functional attributes of weed communities, taking into account both the potential detrimental effects of weeds on crop growth and yield and the potential ecological services or dis-services. Knowledge on the outcome of positive and negative effects will be useful in the context of evaluating soil conservation practices in organic farming. In this paper we highlight the approach used to build the weed functional traits database, the first step in this study