Growth response surface for optimizing fertilization in Andean blackberry (Rubus glaucus Benth.) nurseries

Abstract

Fertilization in soils cultivated with the Andean blackberry has been carried out empirically because there is no complete knowledge on its nutrient requirements. Therefore, the aim of this study was to estimate the effect of variable doses of N, P, K and Ca on the growth of thornless Andean blackberry in nurseries. This research was carried out in the nursery of AGROSAVIA C. I. Tibaitata (Mosquera, Colombia) using vitroplantlets sown in peat moss, sand and rice husks (2:1:1). A completely randomized block design with 25 treatments and 15 plants per experiment unit was used. The nutritive solution application frequency was established as every four d for three months with a volume of 44 mL/plant; the concentration was increased each month. Destructive sampling was carried out 30, 60 and 90 d after transplanting, registering plant height, leaf area, root length and volume, number of leaflets, and leaf, stem and root dry matter. Regression models were used establishing significance (P<0.05 and <0.01) between N, P, K and Ca using SAS 9.3. Doses of 36 N, 43 P2O5, 18 K2O, and 9 CaO g/plant improved the root development in terms of dry matter and length and increased the number of leaflets, aerial length and leaf dry matter.

Mineral nutrition and tolerance to Colletotrichum spp. of Andean blackberry (Rubus glaucus Benth.) in nursery

“…The positive response of LA and CCI could be translated into maximum biomass production and physiological indices with the maximum dose of N and the application of the lowest dose of Ca. These results agree with reported by Cardona et al (2018) and Qiang et al (2019), the former authors evaluated the effect of the concentration of N on LA in Andean blackberry and maize (Zea mays L.). They observed a significant increase of LA when the concentration of N was increased and didn't report significant interaction of N and Ca in LA.…”

“…In accordance with the results observed in the response surface models, the application of the lowest dose of K is the most viable from economical point. In addition, the results coincided with the reported by Cardona et al (2018) who did not find a significant effect of different doses of this nutrient on any of the allometric variables of Andean blackberry plants with thorns (R. glaucus Benth.) in the nursery stage.…”

“…Similarly, effects of the K doses were not observed in the height of Corymbia citriodora plants in greenhouse conditions, even when they were cultivated in soil with a low content of this nutrient (Lopo de Sá et al, 2014). The surface models for Sev showed that doses of Ca must be low to potentiate the positive effects of the interaction between N and P, as stated by Cardona et al (2018).…”

“…The only difference between treatments was the dose of Ca applied, being this three times higher in treatment 24. It is inferred that the negative response of Sev, IP, and r observed in the plants that received treatment 24, were influenced by an antagonistic effect with nutrients such as P that can predispose the plant to pathogen attacks, as stated by Cardona et al (2018) and indicates that attention should be paid to the management of P doses in fertilization plans. In addition to the significant effect between treatments and their doses, the negative relationship of Sev with allometric variables in plants with high r can be interpreted as an adverse effect on the physiological development of plants by the pathogen.…”

“…Following the methodology used by Cardona et al (2018), a central composite design was used (Equation 1), through which 25 treatments were defined (Table 1).…”