EFFECT OF THE APPLICATION OF COMPOST, COMPOST-DERIVED HUMIC SUBSTANCES AND VERMICOMPOST ON ZN EXTRACTABILITY AND GROWTH OF WALNUT TREES (JUGLANS REGIA) IN AN ALKALINE SOIL: FIRST SEASON

M. Molina, M. Araya, R. Ortega
The main objective of this study was to evaluate the effect of the application of different organic amendments (OA) on Zn extractability (DTPA-Zn) and growth of walnut trees grown in an Aridisol of natural low available Zn and organic matter contents. Two assays were performed: 1) Soil samples were incubated after receiving the application of three different OA: compost-derived liquid humus (LH) and fulvic acids (FA), and vineyard compost (CO) at two different C rates. No Zn fertilization was added; 2) Walnut plants were grown in 10-L pots during four months. In this case the treatments were a combination of one (CO and vermicompost [VC] from waste water residues) or two (LH and FA) C rates and two Zn rates, ordered using a randomized complete block design with five replicates. Solid OA were applied at planting while humic substances were applied weekly (16 weeks). NPK fertilization and controls (-Zn, -C) were also considered. Plant growth parameters were monitored along the season. In the incubation experiment, the Zn extractability was increased by the C rate (p<0.05) and a significant positive correlation was found between water soluble C and DTPA-Zn. In the pot experiment, the Zn extractability was highly affected by the Zn and C source (p<0.05). At the lowest Zn rate, the humic substances were more efficient than CO in increasing the DTPA-Zn in comparison to the respective control (+Zn, -C). At this Zn rate, VC and FA were the most efficient increasing DTPA-Zn, When the Zn rate was increased, the presence of CO, FA and LH decreased the Zn extractability in comparison to the respective control (+Zn, -C) indicating strong soil-OM-Zn interactions. At this Zn rate only the VC-treated soil showed a Zn extractability higher than that control treatment (p<0.05). The greatest number of sprouts and leaves were obtained with the equivalent application of 24 kg Zn/ha -C, and with 12 kg Zn/ha + FA at the lowest C rate.
Molina, M., Araya, M. and Ortega, R. (2015). EFFECT OF THE APPLICATION OF COMPOST, COMPOST-DERIVED HUMIC SUBSTANCES AND VERMICOMPOST ON ZN EXTRACTABILITY AND GROWTH OF WALNUT TREES (JUGLANS REGIA) IN AN ALKALINE SOIL: FIRST SEASON. Acta Hortic. 1076, 241-247
DOI: 10.17660/ActaHortic.2015.1076.28
https://doi.org/10.17660/ActaHortic.2015.1076.28
liquid humus, humic acids, fulvic acids, Zn availability, integrated nutrition management
English

Acta Horticulturae