Weed Vegetation Structure in an Area of Organic Acerola Cultivation, Parnaíba, Piauí, Brazil

Abstract

This study aimed to identify and quantify the weed species in an area of organic acerola cultivation in the Distrito de Irrigação dos Tabuleiros Litorâneos do Piauí (DITALPI) in Parnaíba, Piauí, Brazil. Phytosociological sampling was completed in the rainy season, before the farmers adopted management techniques for the plants. Thirty plots of 0.25 m2 were sampled. The plots were located between crop rows, which consisted of herbaceous-subshrub plants. The absolute and relative covers and the absolute and relative frequencies of each species were calculated based on the occurrence and cover of each species. In total, 25 species comprising 13 families were registered, among which the Poaceae family that presented the largest number of species. Commelina benghalensis occurred the most frequently overall. Shannon’s diversity index (H’) and evenness were calculated as 2.30 nats ind-1 and 0.69, respectively. Five species accounted for 79.33% of absolute cover at DITALPI. The species were distributed heterogeneously within the field, and Commelina benghalensis, Urochloa plantaginea, Panicum maximum, Amaranthus spinosus, Cynodonsp., and Cyperus aggregatus were the species most likely to infest the acerola crop. As DITALPI is an area of organic cultivation, understanding these species is essential to help farmers select the best form of control.

Levantamento Fitossociológico De Plantas Daninhas Em Cultivos De Abacaxi Em Diferentes Épocas

“…As famílias que mais se destacaram foram Poaceae e Euphorbiaceae com 34,62% e 11,54% das espécies encontradas, respectivamente. Essas famílias são frequentemente apontadas como os principais grupos de plantas daninhas quanto ao número de espécies, tanto em cultivos de abacaxi (Sarmento et al, 2017), como em outras culturas frutíferas tais como acerola (Sousa et al, 2020), mamão (Costa et al, 2019) e banana (Ávila et al, 2020).…”

“…Espécies de Amaranthus sp. também foram encontradas em levantamentos realizados em frutíferas como acerola (SOUSA et al, 2020) e mamão (COSTA et al, 2019).…”

Multiscale properties of weeds in no-till system

“…The capacity dimension (D 0 ) describes a global view of the system (Leiva et al, 2019;Siqueira et al, 2022), allowing us to verify how the scales are filled by the measurement values. Variations in D 0 values for R. raphanistrum, Commelina ssp., and OW on the sampling dates showed that the scales were filled with measurement values, indicating that the difference in D 0 values for the species under study reflects their ecology (Booth et al, 2003;Brighenti, Oliveira, 2011), mainly with regard to the aggregated distribution (Cheam, Code, 1995;Schaffrath et al, 2007;Chiba et al, 2010;Siqueira et al, 2016;Pereira et al, 2018;Izquierdo et al, 2020;Sousa et al, 2020;Jurado-Expósito et al, 2021). The D 1 dimension is related to the entropy information and quantifies the degree of disorder in the system.…”

“…As for Commelina ssp. (L.), Brighenti and Oliveira (2011) describe the species as being resistant to chemical management with glyphosate, and, according to Sousa et al (2020), its control is hindered due to the low efficiency of mechanical methods since its rapid reproduction occurs vegetatively or through seeds. Hence, during the present research period, the species with the most significant expression presented different reproductive and occupational strategies, resulting in high spatial variability and variability scale.…”