Production of biofertilizers using baker's yeast effluent and their application to wheat and barley grown in north Sinai deserts

Abstract

Effluent from the baker's yeast industry was experimented on as a culture medium for the growth and biomass production of diazotrophs. The effluent supported good growth of Azotobacter chroococcum, Enterobacter agglomerans and Klebsiella pneuomoniae, Azospirillum brasilense, Bacillus polymyxa and Pseudomonas putida and strongly proposed for biofertilizers production of associative diazotrophs. Slurry preparations containing natural polymers, e.g. Arabic gum (5%), pero-dextrin (20%), starch granules (10%) or gelatine (20%) were impregnated with cells of tested diazotrophs. With storage, entrapped cells of B. polymyxa were viable up to 160 days, while gradual decreases in Azospirillum numbers were recorded. Pero-dextrin, a by-product of the starch industry, was selected as the appropriate biocarrier accommodating diazotroph cells and maintaining prolonged survival rates and nitrogenase activity. Cell cultures of A. brasilense, A. chroococcum, B. polymyxa, E. agglomerans and P. putida were equally mixed and entrapped into pero-dextrin slurry biofertilizer formulation named as “BIOGRAMINA”. Tested diazotrophs successfully survived (ca. 10⁸ cfu ml^?1) in such formulation up to 6 months at both ambient and cold temperatures. The response of wheat and barley to “BIOGRAMINA” in the presence or absence of N fertilizers was evaluated in greenhouse and field trials. Highest total biological yields were recorded for inoculated plants simultaneously supplemented with rational N fertilizer dose.     

自然生长和人为影响下土壤碳氮含量差异及影响因素

[目的]深入探讨环青海湖区近30年未变动放牧草地和耕地土壤碳氮含量影响因素,以期为该区土地利用优化管理提供参考。[方法]基于有幸在该区找到未变动放牧草地和耕地,采用前期研究工作中的多个指标,利用一元和多元回归模型进一步分析土壤碳氮含量主导因素。[结果]该区草地和耕地土壤理化指标基本以30 cm土层深度为界发生明显变化; 从回归模型中可以看出,由于受到人类活动影响,耕地土壤碳氮含量受土壤理化指标影响较小,而草地土壤作为未扰动土壤,在自然发育背景下土壤碳氮主导因素明显多于耕地。[结论]土地利用变化显著影响了土壤性状,在该区减少土地扰动能有效减缓土地荒漠化进程。     

Studies on the volcanic ash soils in the environs of Mt. Daisen

The environs of Mt. Daisen, Tottori Prefecture, are generally mountainous or hilly, and apart rom small areas of alluvial and coastal flats there is little level ground. The volcanic ash soils derived from the quartz biotite hornblende andesitic ejecta occur on the gently undulating foot-hill and on the level ground with exception of alluvial flats. Considering the fact that these soils were formed from not only volcanic ash but the coarser materials, they may be properly called volcanogenous soils. The volcanic ejecta have been deposited on the soils from diluvial series, andesite, basalt, granite, and tertiary sedimentary rocks. It was recognized that in an eruption the large ejecta, such as fine porous pumiceous lapiili descended first, then the smaller Particles such as sands, and finally the smallest, as ashes. All of these deposits have been highly weathered, but the quartz and hornblende remain in a fresh state¹⁾. The author has studied some characteristics of these volcanic ash soils.     

Adsorption of silica in river waters by soils in central Chile

The adsorption of the silica in water by soils was investigated using principal river waters and soils collected in central Chile from about 34° to 41° south latitude. The adsorption of silica in water (y) was linearly proportional to the silica concentration in river waters (x) as shown by the following equation:

y=bx-a

where a and b were constants being subject to the nature of the soils. The silica contentration in river waters appeared to relate closely to the rocks in the catchment area. and was high in rivers from volcanic ash areas. However, the salt concentration had no correlation with the silica concentration, and tended to lower to the southward with an increase in annual precipitation and a decrease in annual mean temperature. Sulphate appreciably lowered the adsorption of silica by soils, although chloride and nitrate had little effect on the adsorption. The a-value, dissolution of silica in pure water, was the largest in paddy and alluvial soils, and both the a- and b-values were less in surface soils .in comparison with those of lower horizons. Soils caused neither adsorption nor dissolution of silica at a certain silica concentration. This silica zero adsorption concentration differed greatly from soil to soil, and the largest value which was observed in the surface soil of an irrigated paddy soil was so large that it could not adsorb silica from any river water in the central Chile. In contrast to this soil, an imogolitic subsoil of an Ando soil exhibited the highest adsorption concentration, i.e. it was possible to adsorb silica from every river water in the central Chile. Humus seemed to protect soil silica from dissolution and at the same time to prevent adsorption of silica by soils. Allophanic colloids were labile in water without humic-material, readily releasing silica into the water.     

Mineralization and microbial biomass formation in upland soil amended with some tropical plant residues at different temperatures

A model experiment was carried out at 15, 25, and 35°C to investigate the changes in microbial biomass and the pattern of mineralization in upland soil during 8 weeks following the addition of 8 organic materials including 6 tropical plant residues, ipil ipil (Leucaena leucocephala), azolla (Azolla pinnata), water hyacinth (Eichhornia crassipes), dhaincha (Sesbania rostrata), cowpea (Vigna unguiculata), and sunhemp (Crotalaria juncea). The amounts of CO₂-C evolved and inorganic N produced at 35°C were about 2 times larger than those at 15°C. At any temperature, the flush decomposition of C was observed within the first week and thereafter the rate of mineralization became relatively slow. A negative correlation was observed between inorganic N and C/N ratios of the added organic materials. The relationships between the amounts of cellulose or cellulose plus hemicellulose and the amount of mineralized N of the added organic materials were also negative.

The changes in the microbial biomass were affected by temperatures. The amount of biomass C and N was maximum after 42 d of incubation at 15°C, and after 7 d at 25 and 35°C, and thereafter decreased. The rate of biomass decline was slower at 15°C and faster at 35°C than at 25°C. Regardless of the temperatures, the addition of organic materials enhanced microbial biomass formation throughout the incubation periods.     

Comparison of 15N natural abundance and difference methods for estimating N2 fixation of soybeans grown in a tropical soil

Abstract

A study was carried out to compare the difference or N-yield method with the ¹⁵N natural abundance method for the estimation of the fractional contribution of biological N₂ fixation in the different plant parts of nodulating and non-nodulating isolines of soybeans. The results indicated that the δ¹⁵N values of most plant parts of soybeans were significantly lower (p<0.05) in the nodulating than in the non-nodulating isoline. However, in the case of the root+nodule component, the δ¹⁵N value was higher in the nodulating than in the non-nodulating isoline possibly due to isotopic discrimination of ¹⁵N over ¹⁴N which may have occurred in the nodules. Inoculation of soybeans with the Bradyrhizobium japonicum strain CB 1809 increased significantly (p<0.05) the δ¹⁵N value of the root+nodule component implying that the effectiveness of the soybean-rhizobium symbiosis had increased by inoculation.

Percentage of plant N derived from atmospheric N₂ fixation (%Ndfa) estimated by the ¹⁵N natural abundance method was highly correlated (r=0.762, p<0.01) with that by the difference or N-yield method and the differences between the two methods were not statistically significant. The agreement between the two methods was closer at maturity than at the early reproductive stage.

The %Ndfa obtained by the difference method ranged from 48.4 to 92.6% whereas the %Ndfa obtained by the ¹⁵N natural abundance method ranged from 43.2 to 92.4% in the different plant parts. Based on the ¹⁵N natural abundance method, approximately 15% of the N in pod, shoot, grain, and shell was derived from the soil but in the case of stover, this fraction was about 55%.     

Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes

The consequences of introducing Cichla cf. monoculus Spix & Agassiz, Astronotus ocellatus (Agassiz) and Pygocentrus nattereri Kner into lakes in the River Doce basin, Brazil, on richness, diversity and efficiency of aquatic macrophytes as natural refugia to native fishes was investigated. Samples were taken from lakes with and without alien fishes in areas with and without aquatic macrophytes. The presence of alien fishes reduced richness and diversity of the native fish community. The refugia function, which could be attributed to the clustering of aquatic macrophytes, does not exist in these lakes probably because the alien fishes exploit such habitats for reproduction. Since introductions threaten the native fish diversity of the region, studies on regional dispersion and factors that minimise the spread of alien fishes are needed.     

Co-operative fisheries management of the cross border Lake Peipsi-Pihkva

This paper focuses on the management and socio-economic principles for allocation of the commercial fish resources of Lake Peipsi-Pihkva. The fish resources of this cross border lake are very important both for Russia and Estonia. Recent changes in the Estonian and Russian economies, and the appearance of the state border dividing the lake, have resulted in deep changes in economic, social and legal issues related to the fishery. As the lake is now an international waterbody, the Intergovernmental Estonian–Russian Fishery Commission (ERFC) agreed for co-operative management measures annually from 1994. The ERFC is responsible for all general decisions on management strategies and technical measures used in fishery management. The stocks of most commercial fish species in Lake Peipsi-Pihkva are still abundant, and the economic status of the fishermen is relatively good. It may be concluded that co-operative management of the Lake Peipsi-Pihkva fisheries have been successful.     

Use of local ecological knowledge,scientist's observations and grey literature to assess marine species at risk in a tropical eastern Pacific estuary

• 1. The loss of marine biodiversity in tropical regions of the world is a major threat to human welfare. Multiple anthropogenic drivers are responsible for this situation, with complex scenarios for coastal areas in third‐world countries, where economic development often competes with conservation plans.
• 2. The International Union for the Conservation of Nature (IUCN) Red List of Threatened Species is an influential tool for setting conservation priorities at local and regional levels. The application of IUCN criteria for assessing extinction risk, however, continues to represent a major challenge in data‐poor situations present in many tropical megadiverse countries.
• 3. To overcome these difficulties, three different data sources on invertebrates and fishes present in an estuarine system representative of the tropical eastern Pacific (TEP) region (Bahía Málaga, Colombia) have been used to establish their relative local extinction risk and correlate this information with the existing IUCN Red List categories. Data sources included (1) IUCN global and national listings, (2) traditional ecological knowledge (TEK), and (3) grey literature, scientific and natural history observations.
• 4. In total, 46 threatened species were evaluated after combining the three data sources. Only 17 species were previously identified as threatened by IUCN global and national listings, whereas the remaining 29 species were classified under a threatened category after evaluating TEK, grey literature and scientific information. Some of these species are seriously threatened within the estuary because of overharvesting and habitat destruction.
• 5. Despite most of the species identified having large geographical ranges in the TEP, they may face the same threats throughout their ranges. The approach provides a useful tool to assess species extinction risk in tropical regions where resource exploitation and habitat degradation advance rapidly, making the setting of conservation priorities an urgent task. Copyright © 2011 John Wiley & Sons, Ltd.

     

A niche-based gap analysis for the conservation of odonate species in the Brazilian Amazon

1. Despite the current rates of deforestation and the expected climatic changes, protecting species in their natural habitats is still the simplest, cheapest, and most effective way of safeguarding biodiversity. Here, the network of protected areas in the Brazilian Amazon was evaluated to assess its effectiveness in safeguarding species of Odonata.
2. Ecological niche models were built to assess the suitability of the habitat for 503 Amazonian odonate species. Then, the effectiveness for the protection of odonate species of three classes of protected areas (strictly protected area, sustainable use area, and indigenous territory) was evaluated.
3. Approximately 30% of the species are protected within the network of protected areas. These findings highlight the importance of protected areas for safeguarding most odonate species in the Amazon. For under-represented or gap species, additional resources are still needed for effective management and protection on some private properties, which need to set aside land for conservation. In this way, it is possible to preserve habitats for odonate species and guarantee their conservation in the Amazon.