Blue-green algae in rice soils of Jogjakarta,central Java

Preliminary studies were made to evaluate the role of the blue-green algae in flooded rice soils in the Jogjakarta district of central Java. They included identification of the components of the blue-green algal populations and the effects of fertilizers. The main findings were: (1) members of the families Nostocaceae (7 genera and 12 species recognized) and Oscillatoriaceae (8 genera and 18 species) were generally more abundant than other families; (2) application of nitrogen and phosphorus fertilizers affected the composition (reduction in numbers of nitrogen-fixing blue-green algae) and total size of the populations (increase in algal biomass); (3) a major role for blue-green algae in the N-economy of flooded soils was indicated.     

Effect of blue-green algae on aggregate stability and rice yield under different irrigation and nitrogen levels

The application of blue-green algae improved the aggregation status of rice field soils under different levels of irrigation and nitrogen fertilizer (urea) and increased the grain yield of rice significantly.     

Nitrogen-fixing microorganisms in paddy soils: VI

During the experimental study of the role of blue-green algae in the nitrogen economy of paddy fields which were hitherto carried out in our laboratory, it was observed that small animals in paddy fields such as water fleas, mud snails, small freshwater fish, tadopoles or larvae of small insects had a preference for feeding on blue-green algae.     

Plant and soil responses to a commercial blue-green algae inoculant

A commercial blue-green algae inoculant (Genesis II) for improving the N content of soils was applied to basalt and pumice soils in a greenhouse pot test with orchardgrass, pinegrass, Douglasfir, and ponderosa pine. Treatments were control (deionized water), live algae, killed algae, live algae plus P, K and S and P, K and S only. Plant biomass yields with live inoculant generally were significantly greater than with the control treatment but were the same as with killed inoculant. Live algae plus P, K and S further enhanced productivity. P, K and S alone produced no increase over the control treatment. Response to the inoculant compared to the control appears to be a result of addition of nutrients present in the inoculant stock solution. Further biomass increases with the P, K and S plus live algae treatment compared to live and dead algae treatments occurred because these nutrients became limiting as N was added. Total organic-N and total C in surface soils were similar in all treatments.When the stock solution was sampled via culture methods, the most prominent species found was Chlorella, a green alga. Anabaena, an N₂ fixing blue-green alga, produced less than one colony per plate on the average. Phormidium, a blue-green alga not found in the inoculant, was dominant on the soil surface at the end of the test suggesting a soil origin for this species. Results indicate that Genesis II probably has very limited potential to enhance blue-green algal populations and, consequently, N of the forest soils used in this test.     

The influence of blue-green algae on the biological amelioration of alkali soils

Summary Virgin alkali (sodic) soils have a high pH and high exchangeable Na and are often barren. Blue-green algae, however, tolerate excess Na and grow extensively on the soil surface in wet seasons. Experiments using a highly degraded alkali soil (silt loam, pH 10.3, electrical conductivity 3.5 dS m^-1, 90% exchangeable Na) were conducted in soil columns, with or without gypsum, in order to study the influence of waterlogging on the growth of indigenous and inoculated blue-green algae and hence, soil reclamation. The growth of indigenous blue-green algae was initially slow in alkali soil, due to the high pH and exchangeable Na, and depressed in gypsum-amended soil, due to excess Ca. Inoculation hastened the establishment of blue-green algae in both the unamended alkali soil and the gypsum-amended soil, overcoming the adverse influence of excess Na in the former and excess Ca in the latter. Gypsum was effective in amelioration (pH 9.05, electrical conductivity 1.2 dS m^-1, 41% exchangeable Na after 11 weeks) but blue-green algae were ineffective even after 17 weeks. In combination with gypsum, blue-green algae had no additional effect, and the C and N increases due to the growth of indigenous or inoculated blue-green algae were insignificant.Alkali soil reclamation by biological methods requires mobilization of Ca from native soil calcite and the exchange of Ca for Na in the exchange complex. The ineffectiveness of blue-green algae was ascribed to their inability to mobilize Ca. It is argued that current theories favouring blue-green algae as a biological amendment to bring about alkali soil reclamation are untenable and are not comparable with an effective chemical amendment such as gypsum.     

Atmospheric nitrogen fixation by photosynthetic microorganisms in a submerged Philippine soil

Photosynthetic nitrogen-fixing microorganisms help maintain the nitrogen level of soil in rice paddies when environmental factors favor the growth of microorganisms. Our studies showed that blue-green algae in particular have a significant role in nitrogen-fixation in light. The most active nitrogen-fixation by microorganisms occurred in the soil shortly after it had been submerged under light. The longer the submergence, the less nitrogen microorganisms were fixed. In a greenhouse experiment, the fixed nitrogen appeared not to be immediately available to the rice plant. The amount of nitrogen that can be fixed in the field by nitrogen-fixing microorganisms in paddy water was estimated using the acetylene reduction method during the rice-growing period. The amount of nitrogen fixation by these microorganisms is not sufficient to account for the amount of nitrogen uptake by rice during the rice-growing period.     

Blue-green algae or Azolla additions on the nitrogen and phosphorus availability and redox potential of a flooded rice soil

Freshly-harvested blue-green algae (20 t ha^?1) or Azolla (20 t ha^?1) were incorporated into a waterlogged rice soil and changes of redox-potential and the availability of nitrogen and phosphorus were measured periodically. The soil progressively became reduced where blue-green algae or Azolla had been incorporated. The rate of N release from Azolla was more rapid than from blue-green algae and the amounts released after 7–35 days of flooding were between 41 and 76% and 12 and 35% respectively. Increased P availability was also recorded in soil following the incorporation of blue-green algae or Azolla and reached highest values after 21 days incubation.     

Dynamics of algal populations and acetylene-reducing activity in five rice soils inoculated with blue-green algae

Summary The dynamics of five inoculated strains of heterocystous blue-green algae (BGA) and indigenous algae were studied for 1 month in 1-m² microplots of five soils previously air-dried or oven-dried. The same soils were then dried and resubmerged for another 2 months to study the effect of controlling algal grazers with neem (Azardirachta indica) seeds on the revival and dynamics of indigenous and inoculated algae. During the month following inoculation, inoculated BGA multiplied to some extend in all soils but never dominated the total algal flora. They rarely dominated the indigeneous heterocystous BGA, and did so only when the growth of N₂-fixing BGA was poor or after the decline of blooms of indigenous strains. Once the soils were dried, two of the five inoculated strains did not reappear. During the 1st month following rewetting, the remaining inoculated strains again exhibited poor growth; however, after 2 months of submergence, inoculated Aulosira fertilissima developed an agronomically significant bloom in neem-treated plots of two soils. Correlations between acetylene-reducing activity and heterocystous BGA populations indicated a major contribution by indigenous BGA and a minor contribution by inoculated BGA to the N₂-fixing activity of the soils during the first experiment and the 1st month of the second experiment. The establishment of inoculated BGA exhibited clear differences among strains but was less affected by the nature of the soil and heat treatment. Neem application might have had a delayed positive effect on the late establishment of inoculated A. fertilissima and favored BGA growth and N₂ fixation by the total algal population.Visiting Scientist at IRRI     

池塘三维植被网生态坡水质净化调控系统

为研究养殖池塘三维植被网护坡技术及其水质净化调控效果,试验用三维植被网、布水管和水生植物等构建池塘生态坡净化调控系统。研究发现,池塘三维植被网生态坡净化调控系统具有潜流湿地和表流湿地双重特点,空隙率为4%～9%,构建坡度应低于1:2.5,水流速度应高于0.13m/s。在池塘水体日循环量10%情况下,三维植被网生态坡可使池塘水体中氨氮、亚硝态氮、硝态氮、总氮和总磷的浓度下降46%、65%、49.2%、64.4%和39%,使养殖水体中叶绿素a浓度下降8.8%;生态坡对水体中总氮、总磷、COD的净化效率分别为0.27、0.015和0.94g/h.m2。与对照池相比,试验期间,三维植被网生态护坡池塘水体中的绿藻种类比对照池塘增加了10.7%,蓝藻种类减少了2.5%,藻类ShannonWiener多样性指数(H’)增加了38%。同时,试验池塘水体中的藻类密度下降了23%,其中蓝藻密度下降48.4%,隐藻、裸藻密度分别增加了24%和34%,藻类优势种群结构组成更有利于养殖需要。研究表明池塘三维植被网生态坡系统具有保护池埂和净化调控水质效果,是一种"经济、生态、减排"的护坡技术。     

Nitrogen-fixing microorganisms in paddy soils (Part 3) distribution of non-sulphur purple bacteria in paddy soils

The possible significance of blue-green algae in the nitrogen economy of paddy soil has been pointed out by many investigators.     

氮磷比对两种蓝藻生长及竞争的影响

通过室内实验研究了不同氮磷比条件下主要水华藻类——铜绿微囊藻（Microcystis aeruginisa）和巨颤藻（Oscillatoria princeps）的生长和种间竞争。结果表明,无论在纯培养体系还是混合培养体系中,微囊藻在中氮磷比（N/P=4.5）下生长最好,颤藻在低氮磷比（N/P=0.45）下生长最好;氮磷比对藻类的种间竞争抑制参数能够产生明显影响,中氮磷比时微囊藻对颤藻的竞争抑制参数最大,分别是高氮磷比（N/P=45）和低氮磷比时的1.38倍和1.35倍;而颤藻对微囊藻的竞争抑制参数则是在低氮磷比时最大,分别是高氮磷比和中氮磷比时的2.22倍和4.02倍。中、高氮磷比时微囊藻对颤藻的竞争抑制参数（α）大于颤藻对微囊藻的竞争抑制参数（β）,而低氮磷比时则相反。根据Lotka-Volterra竞争模型中两物种的竞争结局可初步判断,中、高氮磷比时,微囊藻在竞争中占优势,低氮磷比时,微囊藻和颤藻不稳定共存。     

宜兴市稻田表层土壤生物固氮量的空间分异特征

通过对水稻土的系统采样,利用乙炔还原法估算宜兴市稻田土壤的生物固氮量;采用地统计学方法,对稻田土壤的生物固氮量空间变异特征进行分析。结果表明:研究区单位面积生物固氮量范围为0.75～46.85 g/m~2,均值8.04 g/m~2。采用普通克里格法对采样数据进行了空间插值,稻田土壤的生物固氮量总体呈带状分布,高值区位于研究区西南和东南方向靠近丘陵地区,低值区则位于研究区西北和东北方向地势平坦的区域。地统计学中的变异系数和块金值均表明稻田土壤的生物固氮量属中等空间变异,即研究区内稻田土壤的生物固氮量受到结构性变异和随机变异的共同影响。可见,人为经营活动与自然环境共同影响着稻田土壤的生物固氮量。     

Use of blue-green algae and bryophyte biomass as a source of nitrogen for oil-seed rape

Summary Blue-green algal (Nostoc muscorum) or bryophyte (Barbula recurvirostra) growth on the surface of a brown earth silt loam contained in flooded columns significantly increased soil C (+20.9% and ±23.0%, respectively) and soil N (+25.1% and +9.6%, respectively) after 5 weeks in the surface 0.7-cm soil layer. Differences in the lower layers were not significant since there was no movement of C or N metabolites down the profile, even after 21 weeks. The input of C by the inoculated blue-green algae was estimated at 0.48 Mg C 100^-1 g soil or 0.45g C ha^-1; the bryophyte growth gave 0.5 Mg C ha^-1. N fixation by the blue-green algae alone was estimated at 60 kg N ha^-1 after 5 weeks of growth. Blue-green algae associated with bryophyte growth had fixed 23 kg N ha^-1 after 5 weeks, rising to 40 kg ha^-1 after 21 weeks. Decomposition of the bryophyte biomass led to a significant increase in the dry weight (+16.8%) and the N uptake (+27.5%) of spring oil-seed rape planted in homogenised soil. In contrast, soil incorporation of the blue-green algal biomass had no significant effect on yield. The equivalent mineralized N from the blue-green algal and bryophyte incorporation was estimated as 24 and 58 kg N ha^-1, respectively.     

The effect of surface growth of blue-green algae and bryophytes on some microbiological,biochemical, and physical soil properties

Summary The influence of surface growth of inoculated cyanobacteria (blue-green algae) on subsurface properties of a brown earth, silt loam soil was studied in reconstituted flooded soil columns. One blue-green algae species, Nostoc muscorum, become dominant within the first 7 days of inoculation. In light control columns (not inoculated) a bryophyte, Barbula recurvirostra, was dominant although significant growth of indigenous blue-green algae occurred. The blue-green algae counts were in the range of 1×10⁶ g^-1 dry soil in the surface layer (0–0.7 cm) in both columns. Any effect of surface phototrophic growth on soil properties was restricted to the surface layer. In inoculated columns there was a twofold increase in microbial biomass and an eightfold increase in bacterial numbers by week 13. However, bacterial numbers declined so that there was only a 2.8-fold increase by week 21. Dehydrogenase (x2.1), urease (x2.8) and phosphatase (x3.1) activities and polysaccharides (+69%) increased by week 21 as a result of the blue-green algae inoculation along with a significant improvement in soil aggregation. However, similar increases occurred in the light control columns, indicating that given appropriate conditions of light and moisture indigenous species may be ultimately as effective as introduced species in bringing about biochemical and microbiological changes to soil.     

蓝藻厌氧发酵产沼气机械搅拌工艺优化及中试验证

在蓝藻厌氧发酵过程中,由于蓝藻密度较小,容易在反应器中上浮而结壳,从而降低反应器产气效率。该文以蓝藻为原料,研究机械搅拌对其厌氧发酵产沼气的影响。分别选取不同的搅拌周期、搅拌持续时间及搅拌强度3个因素,在试验的基础上采用响应曲面法确定蓝藻厌氧发酵产气的最佳搅拌因素,为蓝藻厌氧发酵产沼气技术应用提供技术参数。以模拟得到的二次多项式回归方程,从而预测得到蓝藻最佳搅拌条件为:搅拌周期6 h、搅拌持续时间20 min/次、搅拌强度56 r/min。中试中,在最佳搅拌条件下,蓝藻的比产气速率、比产甲烷速率最大,分别为0.39、0.236 L/(L·g)。研究发现:搅拌强度对蓝藻厌氧发酵产沼气影响最大,搅拌周期其次,搅拌持续时间最小;搅拌强度过大、搅拌频繁将会破坏适于特定厌氧微生物生长的微环境,使系统中不同种属厌氧微生物的协同作用受到局部破坏,反应器中污泥的蛋白酶、脱氢酶及辅酶活性下降,产气率降低;搅拌强度小、搅拌周期长,蓝藻容易上浮,与污泥中微生物接触有效接触减少,蓝藻转换效率低,微生物活性降低。适当的搅拌混合可以破坏蓝藻上浮结壳,同时提高蓝藻与微生物之间接触效果及产气效率。     

Microbial transformation of nitrogen compounds in soils of the southern taiga

The intensity of the processes of nitrogen mineralization, fixation, and denitrification was assessed in the high-moor peat gley, white-podzolic, pale-podzolic, burozem, low-moor peat, and soddy-gley soils of the Central Forest Biosphere Reserve (CFBR). The actual and potential activities of the nitrogen fixation and denitrification were determined using the gas-chromatographic method, and the intensity of the ammonification was determined using ion-selective electrodes. The maximum intensity of the nitrogen fixation was observed in the low-moor peat and soddy-gley soils, which are characterized by a high content of organic matter. High denitrification activity was found in the low-moor peat soil (0.31 nmol N₂O/g per h); this was determined by the excessive moistening of this soil. The processes of organic nitrogen mineralization were the most intensive in the upper (L and F) subhorizons of the litter.     

Effect of green manuring,blue-green algae and neem-cake-coated urea on wetland rice (Oryza sativa L.)

Summary A field trial was set up to examine the effect of green manuring, blue-green algae, and neem-cake-coated urea on a rice crop. Summer green manuring using Sesbania aculeata increased the crop yield. Inoculation of blue-green algae increased the rice grain yield when 60 kg N ha^-1 was applied as prilled urea, but the increase in grain yield was greater when 60 kg N ha^-1 was applied as neem-cake-coated urea. The results of the present study show that applications of green manure, neem-cake-coated urea, and blue-green algae are complementary and that the three treatments can be used together in the rice ecosystem. The green manure and the fertilizer treatments had no effect on the algal flora of the soil.     

Toxic Effect of Certain Metals Mixture on Some Physiological and Morphological Characteristics of Freshwater Algae

The toxic effect of multi metals mixture which exist simultaneously in aquatic ecosystem on natural phytoplankton assemblages (green algae, blue-green algae and diatoms) was studied. For this purpose a laboratory scale unit was designed to evaluate the effect of continuous flow metals mixture in forms if triple and penta metals in Nile water algae. Clear changes in algal biomass in terms of chlorophyll a (chl a) took place when subjected to metals combination. The rise or decline in chl a was in relation with other algal pigments (chl b, chl c, carotenoides and phenophytin), protein and carbohydrate content of algal cells. Substantial changes in phytoplankton community structure was detected and the most tolerant group was blue-green algae followed by green algae while diatoms was the most sensitive group. The most dominant species in all cases were blue-green alga Oscillatoria mougeotii and green alga Scenedesmus quadricauda. In addition clear changes in morphological shape was observed for tolerant species belonging to the three algal groups. Nile water algae has ability to remove and accumulate metals in the following order therefore Zn > Cd > Ni > Cu > Cr. In addition, phytoplankton has ability to recovered from the stress of metals when eliminated from the media and the recovered biomass was nearly equivalent to that before exposing to metals stress. The overall effect of metals mixture depending on the type and number of metals, the algal community structure and ratio between different morphological forms of algae (unicellular, colonial and filamentous).     

Biological activities of “beaver landscape” soils

This study considers microbiological activities in soils occupied by beaver populations. The intensities of nitrogen fixation, denitrification, and carbon and methane emissions were evaluated, the specific and functional diversities of microbial communities were identified, and the contents of nitrogen and carbon in the altered landscapes were measured. It was shown that nitrogen and carbon are transformed more intensively in the given soils than in the background soils, and accumulation of carbon and nitrogen in the former soils occurs.     

Plankton associations and related factors in a hypereutrophic lake

Cluster analysis was used to group samples collected from ten stations in Moses Lake, Washington, according to the similarity of their contained algal species. During the period 1968 to 1970, nine recurring distinct sample groups, or algal populations, were identified. Of the nine, three were most distinct; they consistently recurred at the same stations, and were dominated by diatom, green, and blue-green algae, respectively. Of the six species of blue-greens that characterized that population, the recreationally nuisance forms,Aphanizomenon flos-aquae andMicrocystis aeruginosa, were dominant. The blue-green population was the most widespread in the lake and occurred in waters that were warmest and contained the lowest concentrations of inorganic nutrients: N, P, and C. Green algae dominated in waters that received treated sewage effluent and contained relatively high concentrations of nutrients. As the nutrient content declined when proceeding away from that area, blue-green algae became dominant. Temporal variation in biomass (chlorophyll content) of the blue-green population was inversely related to phosphate content, but not to the other nutrients. These results support the hypothesis that nuisance blue-green algae dominate in shallow eutrophic lakes during warm summer months when ambient nutrient content is low because, under these conditions, they apparently out-compete other forms for nutrients. In shallow unstable eutrophic lakes like Moses Lake, the nutrient supply rate from sediments may be considered great although ambient concentrations are low which allow the dominating blue-green population to reach a large biomass, e. g., maximums as high as 300 µg l^?1 chlorophyll were observed. Because correlation analysis andin situ bioassays showed that biomass of blue-green algae was most closely related to inorganic phosphate even at times when nitrate was very low and invariable, we suggest that phosphorus availability is most critical to biomass formation. Control of ambient phosphorus content, therefore, would be most apt to result in a reduction in maximum biomass of the blue-greens. Phosphorus control would be unlikely to alter algal dominance in this shallow lake, however, since blue-greens seem to be generally favored over other populations by reduction in nutrient concentration during warm weather.