COMPORTAMIENTO DEL BANCO DE SEMILLAS DE MALEZAS EN SIEMBRA DIRECTA EN UNA ROTACIÓN AGRÍCOLA (DPTO. RÍO CUARTO-CÓRDOBA)

AMUCHASTEGUI, MARIA ANDREA; FORESTO, EMILIANO; NUÑEZ, CESAR OMAR; ZORZA, EDGARDO; MULKO, JOSE

Rosario, Santa Fe

Congreso; II Congreso Argentino de Malezas - ASACIM; 2018

ASASIM

The weeds that emerge in agricultural fields come from the soil seed bank (SSB). The changes that occur in it are of vital importance for the management of weeds and generate variations in the emergence of the same. The objective of this work was to evaluate the behavior of transient SSB of weeds in a corn-soybean rotation with direct sowing, characterizing its size and floristic composition. For this, an essay was carried out with summer crops, in the establishment "Pozo del Carril", experimental field of F.A.V.-U.N.R.C. where it was sampled at the depth of 0-5 cm, in the month of March, on stubble of soya, in three different years: 2003 (P1), 2006 (P2) and 2010 (P3). Using the washing and sieving method, the size of the SSB, richness (S), Specific diversity (H') and Equity (J ') were analyzed. The weed community was composed of 30 species, distributed in 16 families. There were no significant differences in SSB size, although in P3 the largest size was recorded. Higher values of S, H 'and J' were evidenced in P3 being the difference statistically significant. Five annual species contributed 90% to the size of the SSB: Amaranthus hybridus, Bowlesia incana, Digitaria sanguinalis, Eleusine indica and Lamiun amplexicaule. Of which Eleusine indica and Digitaria sanguinalis increased their SSB at P3, while Amaranthus hybridus, Bowlesia incana and Lamiun amplexicaule remained constant. The size of the SSB did not vary, although it modified the contribution of each species, while specific richness and diversity increased towards the last year, for which the SSB showed a tendency to floristic change. It is concluded that the management of the crops carried out in recent years, has not managed to reduce the primary source of weed infestation in crops, on the contrary it has contributed to increase weed richness.