Ma Z.-W.,Xinjiang Institute of Ecology and Geography |
Ma Z.-W.,Cele National Station of Observation and Research for Desert Grassland Ecosystems in Xinjiang |
Ma Z.-W.,Chinese Academy of Sciences |
Ma Z.-W.,University of Chinese Academy of Sciences |
And 12 more authors.
Chinese Journal of Applied Ecology | Year: 2016
The effect of enhanced-efficiency nitrogen (N) fertilizers on emissions of nitrous oxide (N2O) from the grey desert agricultural soils of Xinjiang is uncertain. In this study, the enhanced-efficiency fertilizers, polymer-coated urea (ESN), and stabilized urea with urease and nitrification inhibitors (U+I) were compared to conventional urea (U) for N2O emissions from cotton under plastic mulch drip irrigation near Urumqi, Xinjiang. ESN was added once at planting but the other treatments were added multiple times with drip irrigation during the growing season. Gas samples were collected and analyzed twice per week during the growing season, using the static chamber-chromatography methodology. The results showed that generally, ESN significantly increased soil cumulative N2O emissions during the growing season by 47%-73% compared to other treatments. In the first four months after fertilization, soil ammonium (NH4+-N) and nitrate (NO3--N) concentrations under ESN treatment were generally higher than under other treatments. Thereafter, NH4+-N and NO3--N concentrations under all treatments gradually decreased to similar levels. ESN all added at planting was likely responsible for high NH4+-N and NO3--N concentrations and highest N2O emissions. The U+I treatment reduced soil N2O emission by 9.9% in comparison with U, whereas the difference was not statistically significant. In addition, soil NO3--N contents of the U+I treatments were generally lower than those of the ESN and the U treatments. The cumulative N2O emissions over the growing season ranged from 300 to 500 g N2O-N·hm-2, generally lower than emissions reported for other agricultural ecosystems. Drip irrigation successfully kept moisture conditions below levels for appreciable N2O emissions. Multiple applications of N via drip irrigation seemed to be effective to lower emissions than all N applied at planting. Therefore, for cotton field under plastic mulch drip irrigation in arid land of Northwest China, the benefit of enhanced efficiency N fertilizers on N2O mitigation is limited. © 2016, Science Press. All right reserved.
Li X.Y.,Xinjiang Institute of Ecology and Geography |
Li X.Y.,Cele National Station of Observation and Research for Desert Grassland Ecosystems in Xinjiang |
Lin L.S.,Xinjiang Institute of Ecology and Geography |
Lin L.S.,Cele National Station of Observation and Research for Desert Grassland Ecosystems in Xinjiang |
And 4 more authors.
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011 - Proceedings | Year: 2011
The investigations started from the assumption that perennial plants in the foreland of river oases in the Taklimakan desert are able to take up water from soils of low water content and low water potential during long drought periods. In order to check this assumption, P-V curves were established and selected water relation parameters were derived. Alhagi sparsifolia, Calligonum caput-medusae, Tamarix ramosissima, and Populus euphratica, growing in the foreland of Qira oasis were investigated. Contrary to the expectation, the osmotic potentials both at plant water saturation and at incipient plasmolysis are high in comparison with other desert plants and reveal that the investigated plants do not need to take up water against a low soil water potential. The osmotic potential at incipient plasmolysis is moderately decreasing during the growing season in three of the species, but this seems to be an endogenous process that is not caused by drought stress. Small differences between osmotic potentials at incipient plasmolysis and the minimum plant water potentials that are reached during daily courses point to a transpiration control that accepts very low turgor potentials. A plasmolysis risk is possibly diminished by an increase of cell wall elasticity during the growing season. The results support the conclusion that all investigated species have permanent access to groundwater and live as phreatophytes in the foreland of Qira oasis. © 2011 IEEE.