Use of agro-industry residues as substrate for the production of Euterpe precatoria seedlings

Abstract

The availability of single assai palm (Euterpe precatoria) seedlings with good quality is a fundamental requirement to expand the cultivation of the species. This study aimed to assess the use of fruit agro-industry residues as substrate for producing single assai seedlings. The experiment was carried out under nursery conditions, in a completely randomized design, with four replications and eight plants per plot. Fifteen treatments were evaluated: a commercial substrate, four dry and crushed agro-industrial residues (Brazil nut shell, acerola pit, assai pit and cupuassu peel) and ten combinations of these materials in the proportion of 1:1. The following variables were also measured: shoot height; stem diameter; number of leaves; shoot, root and total dry mass; and Dickson Quality Index score. The substrate formulated with Brazil nut shell + acerola pit stood out for promoting a higher growth and dry biomass, resulting in seedlings with a better quality. The pure assai pit residue was not efficient for producing seedlings, but it showed a good potential when mixed in equal proportion with other materials (e.g. Brazil nut shell and cupuassu peel).

CHEMICAL CONTROL OF Colletotrichum gloeosporioides ON SEEDLINGS OF SINGLE ASSAI PALM

“…After being determined, the DQI was adjusted to the polynomial regression model, whose maximum point was obtained at 0.241 μl of pyraclostrobin + fluxapyroxad, with an estimated value of 3.57 (Figure 4). The DQI obtained in the present study was higher than those reported by Araújo et al, (2020) and Almeida et al, (2018) but lower than the stipulated by Welter et al, (2014) for the E. oleracea species, indicating that this index may vary according to species, management conditions, and interaction between them. Currently, there is no commercial fungicide registered for use in nurseries or even in the field to control anthracnose (Colletotrichum gloeosporoides) in single assai palm, being fundamental studies on active principles.…”

“…The maximum points were obtained at the doses of 0.253 μl for the SDM, 0.241 μl for RDM, and 0.247 μl for the TDM, with estimated values of 7.14 g, 4.91 g, and 12.05 g, respectively. It is important to highlight that biometric variables and dry mass accumulation should not be individually analyzed when evaluating seedling quality (Araújo et al, 2020).…”

“…Although some technologies and innovations have been developed to optimize the seedling production of the single assai palm (Araújo et al, 2020, Almeida et al, 2018, it is important to establish ways to control anthracnose caused by the fungus Colletotrichum gloeosporoides in this palm, as it is the main disease that affects this fruit species in the nursery stage. Due to its high incidence and severity, the previously mentioned disease can lead to up to 70% of seedling death if effective management methods are not adopted, making the implantation and expansion of orchards unfeasible (Nogueira et al, 2016, Nogueira et al, 2017.…”

Initial growth of zinnia seedlings in substrate with different proportions of biosolid

“…The Dickson Quality Index (DQI) is considered a good indicator of seedling quality since it is an integrated morphological measure that considers the robustness and balance of the distribution of the seedling dry biomass (Abreu et al, 2019). Araújo et al (2020), who report that the value for this index can vary according to the species, age of the seedling and to which it was submitted, being considered a minimum value of 0.2. In this way it is possible to observe that all treatments produced seedlings of quality (Figure 2E).…”

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“…Considering its content in lactose, protein and microelements, 10,11 various studies have been carried out to take advantage of whey in human and animal nutrition, in the production of bioplastics and fertilizers (Quille 30 and for agricultural irrigation. 12,13,14 In the Mexican context, where low-tech artisan dairies predominate, 11,40 the use of sweet whey in agricultural applications represents a good option, in addition to contributing to the sustainable production and circular economy of milk by reducing contamination due to poor disposal. In this regard, some studies show that when it is poured into agricultural soil it physically and chemically affects its structure 15 and consequently, agricultural yield decreases.…”