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Fertilization Practices (fertilization + practice)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea communities of an alkaline sandy loam

ENVIRONMENTAL MICROBIOLOGY, Issue 6 2008
Ju-pei Shen
Summary The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities under different long-term (17 years) fertilization practices were investigated using real-time polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE). A sandy loam with pH (H2O) ranging from 8.3 to 8.7 was sampled in years 2006 and 2007, including seven fertilization treatments of control without fertilizers (CK), those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): NP, NK, PK and NPK, half chemical fertilizers NPK plus half organic manure (1/2OMN) and organic manure (OM). The highest bacterial amoA gene copy numbers were found in those treatments receiving N fertilizer. The archaeal amoA gene copy numbers ranging from 1.54 × 107 to 4.25 × 107 per gram of dry soil were significantly higher than those of bacterial amoA genes, ranging from 1.24 × 105 to 2.79 × 106 per gram of dry soil, which indicated a potential role of AOA in nitrification. Ammonia-oxidizing bacteria abundance had significant correlations with soil pH and potential nitrification rates. Denaturing gradient gel electrophoresis patterns revealed that the fertilization resulted in an obvious change of the AOB community, while no significant change of the AOA community was observed among different treatments. Phylogenetic analysis showed a dominance of Nitrosospira -like sequences, while three bands were affiliated with the Nitrosomonas genus. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). These results suggest that long-term fertilization had a significant impact on AOB abundance and composition, while minimal on AOA in the alkaline soil. [source]

Quantitative analyses of the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea of a Chinese upland red soil under long-term fertilization practices

ENVIRONMENTAL MICROBIOLOGY, Issue 9 2007
Ji-zheng He
Summary The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were investigated by using quantitative real-time polymerase chain reaction, cloning and sequencing approaches based on amoA genes. The soil, classified as agri-udic ferrosols with pH (H2O) ranging from 3.7 to 6.0, was sampled in summer and winter from long-term field experimental plots which had received 16 years continuous fertilization treatments, including fallow (CK0), control without fertilizers (CK) and those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): N, NP, NK, PK, NPK and NPK plus organic manure (OM). Population sizes of AOB and AOA changed greatly in response to the different fertilization treatments. The NPK + OM treatment had the highest copy numbers of AOB and AOA amoA genes among the treatments that received mineral fertilizers, whereas the lowest copy numbers were recorded in the N treatment. Ammonia-oxidizing archaea were more abundant than AOB in all the corresponding treatments, with AOA to AOB ratios ranging from 1.02 to 12.36. Significant positive correlations were observed among the population sizes of AOB and AOA, soil pH and potential nitrification rates, indicating that both AOB and AOA played an important role in ammonia oxidation in the soil. Phylogenetic analyses of the amoA gene fragments showed that all AOB sequences from different treatments were affiliated with Nitrosospira or Nitrosospira- like species and grouped into cluster 3, and little difference in AOB community composition was recorded among different treatments. All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin). Cluster M dominated exclusively in the N, NP, NK and PK treatments, indicating a pronounced difference in the community composition of AOA in response to the long-term fertilization treatments. These findings could be fundamental to improve our understanding of the importance of both AOB and AOA in the cycling of nitrogen and other nutrients in terrestrial ecosystems. [source]

Estimation of phosphate adsorption by Acrisols of western Spain from electrical conductivity of potassium dihydrogen phosphate extracts of soil

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2001
R. Espejo Serrano
Summary Estimation of the phosphate adsorption capacity in highly weathered acid soils is crucial for adopting appropriate phosphate fertilization practices. In this work, the salt sorption effect was used to develop a method for estimating phosphate adsorption capacity from the decrease in electrical conductivity of a potassium dihydrogen phosphate solution brought in contact with acidic soil samples from surface and subsurface horizons of Acrisols. The method is fast and simple and requires only the use of a conductimeter. [source]

Mulberry nutrient management for silk production in Hubei Province of China

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 2 2009
Fang Chen
Abstract The silk industry is important for south China's rural economy. Leaves of mulberry (Morus spp.) are used for silkworm production. Hubei province is one of the main silk-producing provinces in China. The objectives of this research were to survey the fertilization practices in the mulberry-producing regions in the province and to determine the best nutrition-management practice for mulberry plantations. A survey and a series of field experiments with N, P, K, and micronutrients were conducted from 2001 to 2002. In addition, a silkworm-growth experiment was also conducted by feeding leaves harvested from various fertilization treatments. The results indicate that poor soil fertility and unbalanced fertilization were the main factors limiting mulberry-leaf yield and quality in Hubei province. Nitrogen fertilization of mulberry has reached a high level (454,kg ha,1 y,1) in Hubei province, but P- and K-fertilization rates have not been matched with N-fertilization rates as farmers are not aware of the significance of P and K. Balanced fertilization showed positive nutrient interactions with respect to mulberry yield and quality. Potassium application increased yield and quality (protein and sugar concentration) of mulberry leaves. Silkworm growth and cocoon quality were improved when silkworms were fed with the leaves derived from K-fertilized plants in comparison with those taken from control plots. Application of Mg, S, and B also significantly improved leaf sugar, essential and total amino acid concentrations, but did not increase leaf yield significantly. It is concluded that a fertilizer dose of 375,kg N ha,1, 66,kg P ha,1, and 125,kg K ha,1 is suitable for the cultivation of mulberry in the Hubei province along with Mg, S, and B, wherever necessary, for the improvement of yield and quality of mulberry leaves. [source]