The aim of the present study was to examine the relationships between weed communities and some pedological and climatic traits in several Italian areas of maize cultivation. Weed data were obtained by gathering the results of several independent studies carried out in the period 1998-2012 by different research organisms and collecting them into a large dataset. The considered studies included herbicide efficacy field trials and weed surveys conducted on a total of about 600 sites, represented by maize fields spread on 175 localities of north and centre Italy. Only data from untreated plots (with size ranging from 10 to more than 100 m2) were considered. Weed data were collected at least once in June or July of each year. In the case of multiple weed surveys per season on a single site, only the observation with the highest number of recorded weed species was considered. Some indices describing the weed community structure were calculated: total number of weed species, number of monocotyledonous species, number of dicotyledonous species, total weed density. In the surveyed sites, additional data on soil (pH reaction, texture, organic matter content, total nitrogen, Mg/K ratio, assimilable phosphorus, cation exchange capacity (CEC), and C/N ratio) and climate (annual total precipitation, annual mean temperature and the climate classification devised by Thornthwaite) were collected or obtained from regional databases. The relationships between pedo-climatic traits and weed indices in the various sites were investigated by using linear correlation analysis (CA), discriminant analysis (DA), and principal component analysis (PCA). In the case of CA, the significance of correlation and the Pearson’s r correlation coefficient were calculated. With DA, pedo climatic traits were tested as predictors of weed indices for the different sites. PCA was mainly aimed at finding hidden relationships between pedo climatic traits and weed indices. The total number of encountered species was equal approximately to 120. Despite the high number of species found, only Chenopodium album, Echinochloa crus-galli, Amaranthus retroflexus, Solanum nigrum and Polygonum persicaria (ordered in term of occurrence frequency) were present on more than 50% of the sites. CA and PCA analyses highlighted a weak tendency for a higher number and density of monocotyledonous species in sandy and alkaline soils. Dicotyledonous species were favoured by clayey soil and high pH values. With DA, a good classification of the surveyed sites on the basis of weed indices was obtained by using soil parameters as predictor variables (>60% of sites correctly classified), in particular in a subset of data referred to Piemonte region only (north-west Italy). Soil texture, CEC, as well as pH and the content of some nutrients, resulted significant in predicting some weed indices. This study pointed out that the weed communities of Italian maize fields are partly influenced by pedo climatic traits. The weakness of some relationships could be the result of a mitigation effect resulting from the overall influence of the crop practices on weed dynamics.

Interactions between summer weed communities and pedo-climatic characteristics in Italian maize fields

VIDOTTO, Francesco;FOGLIATTO, SILVIA;FERRERO, Aldo
2013-01-01

Abstract

The aim of the present study was to examine the relationships between weed communities and some pedological and climatic traits in several Italian areas of maize cultivation. Weed data were obtained by gathering the results of several independent studies carried out in the period 1998-2012 by different research organisms and collecting them into a large dataset. The considered studies included herbicide efficacy field trials and weed surveys conducted on a total of about 600 sites, represented by maize fields spread on 175 localities of north and centre Italy. Only data from untreated plots (with size ranging from 10 to more than 100 m2) were considered. Weed data were collected at least once in June or July of each year. In the case of multiple weed surveys per season on a single site, only the observation with the highest number of recorded weed species was considered. Some indices describing the weed community structure were calculated: total number of weed species, number of monocotyledonous species, number of dicotyledonous species, total weed density. In the surveyed sites, additional data on soil (pH reaction, texture, organic matter content, total nitrogen, Mg/K ratio, assimilable phosphorus, cation exchange capacity (CEC), and C/N ratio) and climate (annual total precipitation, annual mean temperature and the climate classification devised by Thornthwaite) were collected or obtained from regional databases. The relationships between pedo-climatic traits and weed indices in the various sites were investigated by using linear correlation analysis (CA), discriminant analysis (DA), and principal component analysis (PCA). In the case of CA, the significance of correlation and the Pearson’s r correlation coefficient were calculated. With DA, pedo climatic traits were tested as predictors of weed indices for the different sites. PCA was mainly aimed at finding hidden relationships between pedo climatic traits and weed indices. The total number of encountered species was equal approximately to 120. Despite the high number of species found, only Chenopodium album, Echinochloa crus-galli, Amaranthus retroflexus, Solanum nigrum and Polygonum persicaria (ordered in term of occurrence frequency) were present on more than 50% of the sites. CA and PCA analyses highlighted a weak tendency for a higher number and density of monocotyledonous species in sandy and alkaline soils. Dicotyledonous species were favoured by clayey soil and high pH values. With DA, a good classification of the surveyed sites on the basis of weed indices was obtained by using soil parameters as predictor variables (>60% of sites correctly classified), in particular in a subset of data referred to Piemonte region only (north-west Italy). Soil texture, CEC, as well as pH and the content of some nutrients, resulted significant in predicting some weed indices. This study pointed out that the weed communities of Italian maize fields are partly influenced by pedo climatic traits. The weakness of some relationships could be the result of a mitigation effect resulting from the overall influence of the crop practices on weed dynamics.
2013
16th EWRS Symposium
Samsun, Turkey
24/06/2013-27/06/2013
European Weed Research Society - 16th EWRS Symposium
EWRS
123
123
9789080978911
weeds; maize; climate; soil texture
F. Vidotto; S. Fogliatto; A. Ferrero
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/140137
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