Elucidating the factors that determine the effects of temporal and spatial variation of nutrients is important for analyzing the characteristics of an ecosystem. The goal of this paper was to estimate how values obtai...Elucidating the factors that determine the effects of temporal and spatial variation of nutrients is important for analyzing the characteristics of an ecosystem. The goal of this paper was to estimate how values obtained using a particular sampling approach correlated with the actual data for an entire plot. The mesh partition method was employed to divide an integrated observing field (IOF) located at the Haibei National Field Research Station of an alpine grassland ecosystem, China, into 25 subplots. Five of the 25 subplots were randomly selected for soil sampling and to determine the source of variations in soil nutrient content from 2001 to 2012. The results showed that, contributions of temporal and spatial variation in available nitrogen in the 0 - 10 cm soil layer accounted for 47.3% and 52.7%, respectively. The contribution of spatial variance was higher than that of temporal variance especially in the surface soil layers. The available soil nitrogen content in the alpine meadow was not obviously affected by fluctuations in rainfall and temperature. Increasing the number of samples could reduce calculation errors in measuring available soil nitrogen content, while collecting a reasonable number of samples can save time and labor.展开更多
This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Sample...This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Samples were collected along two transect lines during the early summer of 2008. Ward＇s method of hierarchical agglomerative clustering was employed to group the sampling points based on their physico-chemical properties. In this context, the soil samples can be grouped into three major clus- ters： （1） Samples with intensive biological activities, （2） samples from the area recently exposed by glacial retreat and （3） samples from barren and dried areas. Nutrient contents in Punta Fort William are driven by the intensity of biological activities as well as melt water from the Qnito glacier.展开更多
Knowledge of potential anaerobic soil N mineralization is important for nitrogen fertilizer application. Instead of time-consuming laboratory incubation, we attempt to use pedo-transfer functions (PTFs) approach to ge...Knowledge of potential anaerobic soil N mineralization is important for nitrogen fertilizer application. Instead of time-consuming laboratory incubation, we attempt to use pedo-transfer functions (PTFs) approach to get this information. 27 soil samples with various soil depths were collected from paddy field, woodland and tea field in subtropical central China, anaerobically incubated at 35°C for 7 weeks to determine N mineralization, which was fitted by a modified double exponential model with two parameters (the fraction of active N pool (f) and mineralization rate constant (k) for active N pool). The PTFs for parameters were developed from significant soil properties using multiple stepwise regression method. Parameter f (range: 1.59% - 10.4%, mean: 5.2%) was mainly correlated with soil total N (TN), organic C (SOC), sand and silt particle contents (r = -0.59 - 0.69, p k (range: 0.027 - 0.155 d-1, mean: 0.97 d-1) was significantly related to TN, SOC, clay content, C to N ratio and pH (r = -0.6 - 0.71, p f (R2 = 0.72, p TN and pH) for parameter k (R2 = 0.61, p < 0.01). The developed PTFs, integrating various land uses and soil depths, suggest that basic soil properties are helpful for estimation of anaerobic soil N mineralization.展开更多
[Objective] The paper was to study the effects of nitrogen deposition on soil nutrients and soil dissolved organic carbon in forest-grassland landscape in Linzhi, Tibet, and to provide scientific basis and basic data ...[Objective] The paper was to study the effects of nitrogen deposition on soil nutrients and soil dissolved organic carbon in forest-grassland landscape in Linzhi, Tibet, and to provide scientific basis and basic data for understanding and assessing the effect of atmospheric nitrogen deposition on soil nutrients and soil dissolved organic carbon. [Method] From July 2014 to August 2015, in situ nitrogen deposition （CK0 kg· hm^2/a, LN25 kg·hm^2/a, MN 50 kg·hm^2/a, HN 150 kg· hm^2/a） was simulated in the forestgrassland boundary of Zhuqudeng village, Bujiu Township, LinzhiCounty, Tibet. The soil samples were collected for analyzing nutrient and dissolved contents in the soil layer of 0-20 and 20-40 cm. The effects ofdifferent nitrogen deposition levels on soil nutrients and dissolved organic carbon （DOC） were studied. [Result] Nitrogen deposition had significantimpacts on soil organic matter, total N, total P, total K, available N, available P, available K, exchangeable Ca, exchangeable Mg, pH, and DOC（P〈0.05）. （2） With the deepening of nitrogen deposition from CK, LN, MN to HN in the 0-20 cm boundary soil, the contents of organic matter, total N,total P, available P, exchangeable Ca, exchangeable Mg and DOC kept decreasing, and the content of total K and available N increased continuously. The pH increased in LN treatment and decreased in HN treatment, while the available K content was decreased in LN and HN treatment, butincreased in MN treatment. （3） The contents of organic matter, total N, total P, available N, available P, exchangeable Ca, exchangeable Mg andDOC all decreased at the soil layer of 20-40 cm under the same nitrogen deposition. The pH increased in LN treatment, but decreased in HN treatment; the content of total K decreased in LN treatment and increased in MN and HN treatments; the content of available K decreased in LN andHN treatments, but increased in MN treatment. （4） With the deepening of boundary soil layer （0-20 to 20-40 cm）, the organic matter, total N, totalP, available P, available K, exchangeable Ca, exchangeable Mg, DOC showed the same response to simulated nitrogen deposition, while the available N and total K responded differently. [Conclusion] Different levels of N deposition had certain impact on soil nutrient, and the variation of soilnutrients was not the same at different levels.展开更多
[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substr...[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substrate to water and leaching time for the detection of nutrient contents in the substrate by a soil nutrient measuring instrument were discussed firstly, and then the results of nutrient contents measured by the soil nutrient measuring instrument were compared with that by conventional approaches. [ Result] In compadson with the conventional methods, the av- erage content of available nitrogen measured by the soil nutrient measuring instrument was slightly higher, while the average content of available phosphorus measured by the instrument was lower; the average content of available potassium measured by the instrument was close to that by the conventional method. [ Conclusion] This study could provide us a new method to detect available nitrogen, phosphorus and potassium content in seedling substrate efficiently.展开更多
文摘Elucidating the factors that determine the effects of temporal and spatial variation of nutrients is important for analyzing the characteristics of an ecosystem. The goal of this paper was to estimate how values obtained using a particular sampling approach correlated with the actual data for an entire plot. The mesh partition method was employed to divide an integrated observing field (IOF) located at the Haibei National Field Research Station of an alpine grassland ecosystem, China, into 25 subplots. Five of the 25 subplots were randomly selected for soil sampling and to determine the source of variations in soil nutrient content from 2001 to 2012. The results showed that, contributions of temporal and spatial variation in available nitrogen in the 0 - 10 cm soil layer accounted for 47.3% and 52.7%, respectively. The contribution of spatial variance was higher than that of temporal variance especially in the surface soil layers. The available soil nitrogen content in the alpine meadow was not obviously affected by fluctuations in rainfall and temperature. Increasing the number of samples could reduce calculation errors in measuring available soil nitrogen content, while collecting a reasonable number of samples can save time and labor.
基金the Malaysian Antarctic Research Program(MARP)Ministry of Higher Education(MoHE),MalaysiaInstituto Antartico Ecuatoriano(INAE)for sponsoring the study
文摘This study aims to report baseline soil nutrients, specifically the organic carbon, nitrogen and phosphorus profile, in soil samples collected from Puntta Fort William on Greenwich Island in maritime Antarctic. Samples were collected along two transect lines during the early summer of 2008. Ward＇s method of hierarchical agglomerative clustering was employed to group the sampling points based on their physico-chemical properties. In this context, the soil samples can be grouped into three major clus- ters： （1） Samples with intensive biological activities, （2） samples from the area recently exposed by glacial retreat and （3） samples from barren and dried areas. Nutrient contents in Punta Fort William are driven by the intensity of biological activities as well as melt water from the Qnito glacier.
文摘Knowledge of potential anaerobic soil N mineralization is important for nitrogen fertilizer application. Instead of time-consuming laboratory incubation, we attempt to use pedo-transfer functions (PTFs) approach to get this information. 27 soil samples with various soil depths were collected from paddy field, woodland and tea field in subtropical central China, anaerobically incubated at 35°C for 7 weeks to determine N mineralization, which was fitted by a modified double exponential model with two parameters (the fraction of active N pool (f) and mineralization rate constant (k) for active N pool). The PTFs for parameters were developed from significant soil properties using multiple stepwise regression method. Parameter f (range: 1.59% - 10.4%, mean: 5.2%) was mainly correlated with soil total N (TN), organic C (SOC), sand and silt particle contents (r = -0.59 - 0.69, p k (range: 0.027 - 0.155 d-1, mean: 0.97 d-1) was significantly related to TN, SOC, clay content, C to N ratio and pH (r = -0.6 - 0.71, p f (R2 = 0.72, p TN and pH) for parameter k (R2 = 0.61, p < 0.01). The developed PTFs, integrating various land uses and soil depths, suggest that basic soil properties are helpful for estimation of anaerobic soil N mineralization.
基金Supported by National Natural Science Foundation of China(31360119,31460112)Innovative Experimental Project for College Students of Tibet Agriculture & Animal Husbandry University(2015)+1 种基金Pilot Project of Forest Education and Training Plan for Outstanding Talents in Agriculture and Forestry(2016)Key Laboratory of Tibet Plateau Forestry Ecological Engineering
文摘[Objective] The paper was to study the effects of nitrogen deposition on soil nutrients and soil dissolved organic carbon in forest-grassland landscape in Linzhi, Tibet, and to provide scientific basis and basic data for understanding and assessing the effect of atmospheric nitrogen deposition on soil nutrients and soil dissolved organic carbon. [Method] From July 2014 to August 2015, in situ nitrogen deposition （CK0 kg· hm^2/a, LN25 kg·hm^2/a, MN 50 kg·hm^2/a, HN 150 kg· hm^2/a） was simulated in the forestgrassland boundary of Zhuqudeng village, Bujiu Township, LinzhiCounty, Tibet. The soil samples were collected for analyzing nutrient and dissolved contents in the soil layer of 0-20 and 20-40 cm. The effects ofdifferent nitrogen deposition levels on soil nutrients and dissolved organic carbon （DOC） were studied. [Result] Nitrogen deposition had significantimpacts on soil organic matter, total N, total P, total K, available N, available P, available K, exchangeable Ca, exchangeable Mg, pH, and DOC（P〈0.05）. （2） With the deepening of nitrogen deposition from CK, LN, MN to HN in the 0-20 cm boundary soil, the contents of organic matter, total N,total P, available P, exchangeable Ca, exchangeable Mg and DOC kept decreasing, and the content of total K and available N increased continuously. The pH increased in LN treatment and decreased in HN treatment, while the available K content was decreased in LN and HN treatment, butincreased in MN treatment. （3） The contents of organic matter, total N, total P, available N, available P, exchangeable Ca, exchangeable Mg andDOC all decreased at the soil layer of 20-40 cm under the same nitrogen deposition. The pH increased in LN treatment, but decreased in HN treatment; the content of total K decreased in LN treatment and increased in MN and HN treatments; the content of available K decreased in LN andHN treatments, but increased in MN treatment. （4） With the deepening of boundary soil layer （0-20 to 20-40 cm）, the organic matter, total N, totalP, available P, available K, exchangeable Ca, exchangeable Mg, DOC showed the same response to simulated nitrogen deposition, while the available N and total K responded differently. [Conclusion] Different levels of N deposition had certain impact on soil nutrient, and the variation of soilnutrients was not the same at different levels.
基金Supported by the Scientific Research Project of Public Welfare Industry(Agriculture)(201303014-01)Science and Technology Innovation Team of Anhui Academy of Agricultural Sciences(14C0314)the Dean’s Youth Innovation Fund from Anhui Academy of Agricultural Sciences(15B0331)
文摘[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substrate to water and leaching time for the detection of nutrient contents in the substrate by a soil nutrient measuring instrument were discussed firstly, and then the results of nutrient contents measured by the soil nutrient measuring instrument were compared with that by conventional approaches. [ Result] In compadson with the conventional methods, the av- erage content of available nitrogen measured by the soil nutrient measuring instrument was slightly higher, while the average content of available phosphorus measured by the instrument was lower; the average content of available potassium measured by the instrument was close to that by the conventional method. [ Conclusion] This study could provide us a new method to detect available nitrogen, phosphorus and potassium content in seedling substrate efficiently.
