Effects of 15N application frequency on nitrogen uptake efficiency in Citrus trees
Two irrigation systems were used to compare nitrogen uptake efficiency in citrus trees and to evaluate the NO3− runoff in «Navelina» orange trees [Citrus sinensis (L.) Osbeck] on Carrizo citrange rootstock (Citrus sinensis × Poncirus trifoliata Raf.). These were fertilized with 125 g N as labelled K...
| Main Authors: | , , , |
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| Format: | article |
| Language: | Inglés |
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Elsevier
2020
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11939/6579 https://www.sciencedirect.com/science/article/abs/pii/S0176161704705386 |
| Summary: | Two irrigation systems were used to compare nitrogen uptake efficiency in citrus trees and to evaluate the NO3− runoff in «Navelina» orange trees [Citrus sinensis (L.) Osbeck] on Carrizo citrange rootstock (Citrus sinensis × Poncirus trifoliata Raf.). These were fertilized with 125 g N as labelled K15NO3 and grown outdoors in containers filled with a sand-loamy soil. Two groups of 3 trees received this N dose either in five equally split applications by a flooding irrigation system or in 66 applications by drip. Trees were harvested at the end of the vegetative cycle (December) and the isotopic ratios of 15N/14N were measured in the soil-plant system. The N uptake efficiency of the whole tree was higher with drip irrigation (75 percnt;) than with flooding system (64 percnt;). In the 0-90 cm soil profile, the N immobilized in the organic fraction was similar for both irrigation methods (around 13 percnt;), whereas the N retained as NO3− was 1 percnt; of the N applied under drip and 10 percnt; under flooding. In the last case, most of NO3− remained under root system and it could be lost to leaching either by heavy rainfalls or excessive water applications. These results showed that a drip irrigation system was more efficient for improving water use and N uptake from fertilizer, in addition to potentially reduced leaching losses. |
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