Effect of zeolite-amended sandy soils on growth & yield of Copenhagen cabbage

O.A. Sindesi¹*, M.N. Lewu², B. Ncube³, A.R. Mulidzi² & F.B. Lewu¹

¹Lecturer & Researcher, Department of Agriculture, Faculty of Applied Sciences, Cape Peninsula University of Technology, Private Bag X8, Wellington 7654, South Africa
²Senior Researcher, Soil & Water Science Programme, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
³Lecturer & Senior Researcher, Centre for Water & Sanitation Research, Faculty of Engineering & the Built Environment, Cape Peninsula University of Technology, Bellville 7535, Cape Town, South Africa
*Correspondence: olwethusindesi@gmail.com

Abstract:

A greenhouse pot experiment was conducted at the Agricultural Research Council, Infruitec-Nietvoorbij, Stellenbosch, South Africa, to assess the effect of zeolite on the fresh head yield & growth characteristics of cabbage cv. Copenhagen. Zeolite was applied at 0:10, 1:9, 2:8, & 3:7 zeolite to sandy soil (w/w). Cabbage growth parameters, plant height, & number of loose leaves showed significant improvements (p < 0.05) under zeolite-amended treatments in the second growing season. Maximum chlorophyll content index (CCI) values ranged from 70.03 to 78.04 in the first season & 52.37 to 61.59 in the second growing season. While leaf area showed no significant differences (p > 0.05) in the first growing season. Additionally, marketable cabbage head traits (head diameter, head circumference, & fresh weight) exhibited no significant differences (p > 0.05) among treatments in the first season. Still, significant improvements were observed in the second season. Zeolite applications at 30% reduced cabbage yields by 15.12% (without loose outer leaves) & by 11.64% (with outer leaves) compared to a 20% zeolite application. Furthermore, the findings highlight a practical implication: a 20% zeolite amendment appears to be the optimal level for improving cabbage yield without the negative effects observed at higher application rates. Overall, this study revealed that zeolite could enhance certain cabbage growth parameters & yield, particularly in the second season. This indicates that zeolite might require a fallowing period within the soil to fully benefit plant growth. Additionally, the results also indicate that zeolite soil amendment may have a limit to its beneficial effects. To support broader adoption, the study recommends applying zeolite at 20% prior to planting, integrated with conventional fertilisers, and guided by soil testing in follow-up seasons.

Key words:

agronomic characteristics, Brassica oleracea var. capitata L, fresh market vegetables, growth rate, soil amendment

Diatom cultivation and lipid productivity for non-cryopreserved and cryopreserved cells

Z. Demirel*, C. Demirkaya, E. Imamoglu and M. Conk Dalay

Ege University, Faculty of Engineering, Department of Bioengineering, TR 35100 Bornova-Izmir, Turkey
*Correspondence: zelihademirel@gmail.com

Abstract:

Many freshwater and marine algae can be cryopreserved, but typically with lower post-thaw viability levels. However, most of the algae groups (dinoflagellates, cryptophytes, synurophytes, and raphidophytes) cannot be successfully cryopreserved in these days. Marine diatoms can be cryopreserved and frequently have shown great viability. The aim of this study is to compare the cultivation and lipid productivity for non-cryopreserved and cryopreserved marine diatom cells. Diatoms preserved in the EGEMACC (Ege University Microalgae Culture Collection) are usually maintained by serial sub-culturing. In this study, the cryopreservation of marine diatom algae (Amphora cf. capitellata, Cylindrotheca closterium, Nanofrustulum shiloi) using the passive freezing system procedure was studied. Investigation into the cause of the freezing injury at the cellular level was made at different salt concentrations. Passive freezing method used in sea salts liquid media at the percentage of 1%, 2% and 3% containing cryoprotectant of 10% Me2SO for six months in liquid nitrogen. C. closterium was obtained with the highest viability however N. shiloi was revival extended period of time. All of the diatom cells were grown in 1 L sterile bottle containing 900 mL of F/2 medium under the light intensity of 20 μmol photons m-2 s-1 at 22 ± 2 °C with the air flow rate of 1 L/min for 15 days. The growth rate and biomass productivity were determined at the end of the batch production process. Also, lipid content of A. capitellata was obtained at the highest concentration compared to that of the other diatoms.

Key words: