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CO_2 efflux from different forest soils and impact factors in Dinghu Mountain, China

Science China Earth Sciences 2005年第Z1期48卷 198-206页

作者： ZHOU Cunyu, ZHOU Guoyi, ZHANG Deqiang, WANG Yinghong & LIU Shizhong Dinghushan Forest Ecosystem Research Station, Chinese Academy of Sciences, Guangzhou 510650, China Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Dinghushan Forest Ecosystem Research Station Chinese Academy of Sciences Guangzhou 510650 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

CO2 fluxes from soils and related environmental factors were measured in three forest ecosystems of Dinghu Mountain using static chamber-gas chromatograph technique for one year. The seasonal pattern of CO2 flux, contribution of litter on total CO2 flux and the correlations of CO2 flux with soil temperature and soil water content were examined for each type of forest. The results were given as followings: (1) The seasonal patterns of CO2 flux from soil of the three types of forest were similar, with a higher CO2 flux in rainy season than in dry season. The comparative relations of mean annual CO2 fluxes between the three sites were expressed as:monsoon forest ＞ mixed forest ＞ pine forest. (2) CO2 fluxes from litter decomposition in monsoon forest, mixed forest and pine forest accounted for 24.43%, 41.75% and 29.23% of the corresponding total CO2 fluxes from forest floor, respectively. (3) Significant relationships were found between CO2 fluxes and soil temperatures at 5 cm depth for the three types of forest, which could be best described by exponential equations. The calculated Q10 values based on soil temperature at 5 cm depth ranged from 1.86 to 3.24. More significant relationships were found between CO2 fluxes and soil water content when the annual variation coefficients of soil moisture.were higher.

关键词： CO2 flux, litter decomposition, Q10, soil moisture.

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Soil Invertebrates in Different Land Use Systems： How Integrated Production Systems and Seasonality Affect Soil Mesofauna Communities

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Journal of Agricultural Science and Technology(B) 2017年第3期7卷 158-169页

作者： Mauricio Rumenos Guidetti Zagattol Cintia Carla Niva Marcilio Jose Thomazini Dilmar Baretta Alessandra Santos Herlon Nadolny Guilherme Borges Xarao Cardoso George Gardner Brown Luiz de Queiroz College of Agriculture Universidade de Sao Paulo (USP) CEP 13418-260 Piracicaba Sao Paulo Brazil Embrapa Cerrados CEP 73301-970 Planaltina Distrito Federal Brazil Embrapa Florestas CEP 83411-000 Colombo PR Brazil Universidade do Estado de Santa Catarina CEP 89815-630 Chapeco SC Brazil Agricultural Sector Universidade Federal do Parana CEP 80035-050 Curitiba PR Brazil

The soil mesofauna plays a role in organic matter comminution and decomposition, and can be used as bioindicators, since they are sensitive to soil management, vegetation and climate changes. Hence, this study aimed to evaluate mesofauna density and diversity in different land use systems to identify faunal relationships with soil properties, management and seasonality. The study area included five land use systems in Ponta Grossa municipality, Parana State： integrated crop-livestock （ICL）, integrated crop-livestock-forestry （ICLF）, grazed native pasture （NP）, Eucalyptus dunnii plantation （EU） and no-tillage （NT） cropping systems. In each system, eight soil samples for mesofauna were collected with Berlese funnels of 8 cm diameter along a transect in three replicate plots of 50 m × 100 m. For physical and chemical analysis, soil was sampled at five points per plot in two seasons： winter 2012 and autumn 2013. Data were statistically analyzed using ANOVA and Duncan＇s test （P 〈 0.05）, nonparametric statistics （when necessary） and redundancy analysis （RDA）. Diversity was calculated based on the group richness and Simpson index. The main mesofauna groups found were： Acarina, Collembola and Hymenoptera. Diplopoda, Enchytraeidae, Isopoda, Collembola, Hemiptera, Hymenoptera and Coleoptera larvae were more abundant in autumn than winter. Soil moisture.was the main factor responsible for higher mesofauna abundance in autumn. Integrated production systems, especially ICLF had similar invertebrate community abundance and composition with EU, while NT favored Oribatid mites, although the use of insecticides, herbicides and fungicides reduced total mesofauna density. Most correlations between mesofauna and physical-chemical attributes in the winter were not observed in the autumn and vice versa, revealing that there are more factors involved in regulating soil mesofauna distribution.

关键词： Soil invertebrates biodiversity soil management bioindicators seasonality moisture.

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Factors that Affect Pellet Quality： A Review

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Journal of Agricultural Science and Technology(A) 2015年第9期5卷 717-722页

作者： Keysuke Muramatsu Andreia Massuquetto Fabiano Dahlke Alex Maiorka Department of Animal Production Faculty of Veterinary and Animal Science Universidade Federal do Parana Curitiba80035-050 Brazil Department of Animal Production Faculty of Agronomy and Animal Science Universidade Federal de Santa CatarinaFlorianopolis 88040-900 Brazil

Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can only be achieved, if the pellets remain intact until they are ingested by the birds. Many factors may affect pellet physical quality, such as feed nutritional composition, ingredient particle size, conditioning temperature and time, feed moisture. etc.. Despite their importance, sometimes these factors are not managed properly, therefore, pelleted feed may not contain a high amount of intact pellets. In addition, the possible interactions among these variables may yield different responses in comparison with those expected when individual factors are considered. Very few experiments have been conducted to evaluate the impact of combined factors on pellet quality. This may be explained by the presence of many qualitative and quantitative factors in the manufacturing process. Research indicates that heat processing and feed formulation, especially fat inclusion level, are the factors which have the biggest influence on pellet quality. Strategies, such as the expansion process and fat inclusion restriction or post pellet liquid fat application could be implemented to produce high physical quality pellets. More research is needed to identify which factors have a positive or negative effect on pelleting process and to find new strategies to improve pellet physical quality.

关键词： Conditioning broiler feed formulation particle size pellet durability index pellet quality pelleting moisture.

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