Articles
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
Article number
1076_28
Pages
241 – 247
Language
English
Abstract
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.
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.
Authors
M. Molina, M. Araya, R. Ortega
Keywords
liquid humus, humic acids, fulvic acids, Zn availability, integrated nutrition management
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