Abstract :
Keywords: conservation agriculture; cover crop; integrated weed management; mulch in-situ; Urochloa ruziziensis; weed density; weed seed bank; population dynamics Abstract In fruit crops like citrus, weeds coexist throughout their long cycle and can cause several yield losses. Ecological mowing (ECO) is an integrated weed management (IWM) option for citrus, as it produces an in-situ mulch that suppresses the weeds; however, there is a lack of information on the impacts of tree-row conventional (CONV) and ECO mechanical weed control when combined with residual or non-residual herbicides, or standard frequent mechanical (MECH) control. This study aimed to evaluate, for 3years in a young orange orchard, IWM using ECO and conventional mowing when combined with one of five weed control programmes: pre-emergent (PRE) herbicides (sulfentrazone [spring], indaziflam [summer]), post-emergence (POST) herbicides (glyphosate [spring], saflufenacil [summer]), PRE+POST herbicides (sulfentrazone + glyphosate [spring], indaziflam+saflufenacil [summer]) and P/P (pre/post-emergence duality) herbicides (flumioxazin [spring], diuron [summer]). Impacts on cover crop biomass deposition, weed density, population dynamics, biomass accumulation and seed banks were evaluated. Alternanthera tenella Colla (joyweed), Bidens pilosa L. (hairy beggarticks), Digitaria horizontalis Willd (crabgrass), Galinsoga parviflora Cav. (smallflower galinsoga) and Raphanus raphanistrum L. (wild radish) were the most critical weeds with changes in their population dynamics over time. The ECO treatment promoted greater biomass deposition in the tree-rows (up to â8.0 tha.sup.-1), reducing weed density and biomass accumulation by mulch formation; similarly, MECH resulted in low weed density and a reduction in biomass accumulation. The POST and P/P treatments resulted in low levels of weed control, while ECO + PRE+POST led to almost absolute weed control ( 95%). Thus, we suggest ECO + PRE + POST is an efficient IWM option in citrus tree-row crops with low-risk herbicide resistance (up to 5 MoA year.sup.-1+mulch). Article Note: Subject Editor: Francesco Tei University of Perugia, Perugia, Italy. Funding information State of São Paulo Foundation for Research Support, Grant/Award Number: 2020/12004-4; Coordination for the Improvement of Higher Education Personnel, Grant/Award Numbers: 1757830/2018, 88887.144808/2017; National Council for Scientific and Technological Development, Grant/Award Number: 309777/2020-8 CAPTION(S): TABLE S1 Identified weed species in the experimental area and its globally reported herbicide resistance cases. TABLE S2 Weed density of the 17 major weed species identified in the experimental area. Values are averaged over two seasons (spring and summer) and three evaluations (15, 30 and 60days after weed control) for each agricultural year. ECO: ecological mowing; CONV: conventional mowing; MECH: mechanical control; PRE: sulfentrazone (spring), indaziflam (summer); POST: glyphosate (spring), saflufenacil (summer); PRE+POST: sulfentrazone + glyphosate (spring), indaziflam + saflufenacil (summer); P/P: flumioxazin (spring), diuron (summer); ALRTE: Alternanthera tenella, AMARE: Amaranthus retroflexus, BIDPI: Bidens pilosa, BRADC: Urochloa decumbens, CHRSS: Chloris elata, COMBE: Commelina benghalensis, CYNDA: Cynodon dactylon, DIGIN: Digitaria insularis, DIGHO: D. horizontalis, ELEIN: Eleusine indica, EPHHI: Chamaesyce hirta, EPPHL: Euphorbia heterophylla, ERICA: Erigeron canadensis, GASPA: Galinsoga parviflora, PTNHY: Parthenium hysterophorus, RAPRA: Raphanus raphanistrum, RCHBR: Richardia brasiliensis. Byline: Rodrigo Martinelli, Luiz Renato Rufino-Jr., Daniel Rodrigues Desiderio, Ricardo Alcántara-de la Cruz, Patricia Andrea Monquero, Fernando Alves de Azevedo