基于物联网Android平台的水产养殖远程监控系统

为了促进江苏省智能农业的发展,该文开发了一种基于物联网Android平台的水产养殖远程监控系统,实现了对多传感器节点的信息（pH值、温度、水位、溶解氧等环境参数）远程采集和数据存储功能,实现了对多控制节点的远程控制。系统不受时间地域限制,用户可以在任何具备网络覆盖的地方从手机上浏览并获取数据,将数据从数据库中导出到用户的SD卡上,以TXT格式存储,系统多手机用户客户端可以共享一台服务器,具有很高的性价比。系统采用CC2430作为底层管理芯片,控制部分采用模糊PID控制算法,系统通过在江苏省溧阳长荡湖实验基地系统的实际调试,各项指标均达到要求,温度测量精度达到0.5℃,pH值测量精度达到0.3,溶解氧的控制精度在±0.3 mg/L以内,水位波动控制在平均±1 cm左右,能够满足水产养殖的需要。     

基于无线传感器网络的节能型水产养殖自动监控系统

水产养殖的规模化发展和人力成本的不断上升迫切需要建立水质参数的无人值守自动监控系统。该文提出了一种基于改进型低能耗分层分群协议（LEACH）的Zigbee无线传感网络的水质监测和基于西门子PLC的变频增氧控制系统。在LEACH-C通信协议中,由基站根据各节点剩余能量的估算值选定簇首,达到各节点供电电池剩余能量的均衡,同时从系统的实际控制精度出发,当节点测量到的溶解氧浓度值与上次发送值误差在0.02 mg/L范围内时,不向簇首发送数据,达到节约供电电池能量的目的,经试验发现采用优化后的LEACH-C协议,比采用常规的LEACH协议网络有效寿命延长33.33%。适合鲈鱼生长的水体溶解氧质量浓度大于4.5 mg/L,但随着浓度的上升增氧效率将逐步降低,因此设定应急增氧的区间为4.5～5.5 mg/L。控制系统根据无线传感网络测量的溶解氧质量浓度值,采用PI-PID控制水体溶解氧浓度。保证了水体溶解氧质量浓度始终适合鱼类生长。通过试验验证,与人工粗略控制相比,这种控制方法大幅降低了人力成本和节约了51%的电能。该文可为水产养殖自动控制研究提供参考。     

水产养殖参数无线测量网络的长生命周期研究

在水产养殖参数的无线测控网络中,测量节点能耗不均匀,个别节点由于能耗大过早失效,降低了网络的有效生命周期。该文对采用平面路由协议和低能量自适应分群分层路由协议(LEACH)的测控网络进行对比试验,发现采用LEACH协议网络的有效生命周期延长19%以上。在LEACH协议的水质参数测量网络中存在2个缺陷:一方面无线测控网络中每个簇的簇首功耗远远大于普通节点,LEACH协议通过等概率随机选择簇首部分改善了节点能耗的均衡性,但水产养殖参数监控中每个簇首功耗不同,为此在LEACH优化协议中依据节点剩余能量的多少选择簇首,使节点的剩余能量更趋均衡;另一方面水产养殖池中距离基站较远的节点容易提前失效,主要是因为监控面积大,簇首节点与基站采用单跳通信,远距离节点被选为簇首后向基站发送数据通信距离远,路径损耗采用多路径衰落信道模型,衰减指数为4。在优化协议中,对远距离簇首与基站通信采用双跳通信,使路径损耗采用自由空间信道模型,衰减指数为2。试验表明,无线传感网络有效生命周期延长了8%,各节点失效时间更趋接近。     

水产养殖多环境因子控制系统的研究

该文分析了国内工厂化水产养殖的现状和存在的问题，提出了以PC机为上位机，以西门子S7-224 Programmable Logic Controller(简称PLC)为下位机的水产养殖多环境因子的计算机监控系统的设计方案，阐述了系统的硬件和软件实现方法，成功地应用在工厂化养殖鳗鱼生产中。试验结果表明，该系统操作方便，人机界面友好，性能价格比高，实时控制鱼池中的溶氧量、温度、pH值，使多环境因子稳定在最佳值附近。增产节能效果显著，为提高我国工厂化养殖水平提供了一项切实可行的技术措施。     

基于低功耗广域网的海岛水产养殖环境监测系统研制

针对海岛环境中水产养殖区域分散、工作环境恶劣、人工巡检不便等问题,设计了基于低功耗广域物联网的海岛养殖环境监测系统。系统包括集成Arduino和传感器的终端采集节点,通过LoRa技术实现数据汇总和远距离传输的汇聚网关,利用Python与PostgreSQL开发用于数据接收、存储、处理、访问和控制的后台监测系统。通过对网络拓扑复杂度、能耗等方面的评估,表明在海岛环境下部署水产养殖环境监测系统,相比传统Zigbee多跳无线传感网,采用LoRaWAN,其单跳节点覆盖范围更大,而网络复杂度、能耗等更优。测试表明该系统能以较低功耗实现整片区域内远距离数据采集,有效传输养殖区水体环境数据。网络生存期与传输可靠性测试表明,当传感器节点采用3.7 V/4 200 mAh锂电池,上传周期为30 min时,监测网络的有效生存期理论上可达2.4 a;在800 m通信范围内,发射功率为20 mW时,节点丢包率小于3.6%,具有较高的通信可靠性。该研究可为水产养殖生产和物联网应用研究提供有效参考。     

主成分分析和长短时记忆神经网络预测水产养殖水体溶解氧

为了提高水产养殖溶解氧预测的精度,提出了基于主成分分析(principal component analysis,PCA)和长短时记忆神经网络(long short-term memory,LSTM)的水产养殖溶解氧预测模型。首先通过主成分分析提取水产养殖溶解氧的关键影响因子,消除了原始变量之间的相关性,降低了模型输入向量维度;然后,在Tensorflow深度学习框架的基础上建立LSTM神经网络的水产养殖溶解氧预测模型;最后,利用该模型对浙江省淡水水产养殖研究所综合实验基地某池塘溶解氧进行验证。试验结果表明:该模型与BP神经网络等其他浅层模型相比,模型评价指标平均绝对误差、均方根误差和平均绝对误差分别为0.274、0.089和0.147,均优于传统的预测方法;该模型具有良好的预测性能和泛化能力,能够满足水产养殖溶解氧精确预测的实际需要,可以为水产养殖水质精准调控提供参考。     

基于物联网的螃蟹养殖基地监控系统设计及应用

为了促进中国智能渔业的发展,该文开发了一种基于物联网三层体系架构的螃蟹养殖基地监控系统,由水质监控、气象监控、视频监控、智能控制和远程服务中心组成,实现了对螃蟹养殖基地的本地和远程全方位智能监控。该系统采用STC15F2K60S2嵌入式单片机作为底层控制器芯片,通过RS485协议采集传感器数据,实现水质多参数(溶解氧、p H值、温度),气象多参数(温度、湿度、风向、风速、气压、雨量、光照)的监测;视频监控采用萤石云平台,实现养殖基的安防和养殖池塘水上、水下摄像;养殖设备采用PLC控制,实现投饵机、增氧机的智能控制。整个系统组网采用ESP8266 WIFI模块,接入AP基站,通过搭建的服务器管理程序,用户可以通过电脑浏览器或者手机APP在任何具备网络覆盖的地方远程浏览养殖基地数据。该系统应用于上海海洋大学崇明蟹种养殖基地,并对其通信稳定性、数据准确性和Android客户端进行测试,整个系统通信成功率为98%以上,溶解氧平均相对测量误差为0.016 mg/L,温度为0.031℃,p H值为0.023,其他各项指标均达到要求。系统运行到今,稳定可靠,能够满足水产养殖的需要,并可作为示范进行推广应用。     

封闭循环系统对虾合理养殖密度的试验研究

2002年5月～8月在室内工业化养殖温室内进行了高密度封闭循环水养殖凡纳滨对虾(Litopenaeus vannamei)试验，采用人工配制海水(盐度为4)，养殖排放水经过滤、消毒、增氧处理后循环利用，日添加新水量为总循环水量的3%～7％。经86 d养殖，对虾体重从(0.3±0.04)g/尾增加到(10.40±2.04)g/尾，平均产量为5.85 kg/m³，饵料系数为1.76，成活率为67％，该封闭循环养殖系统设计合理，每m³水体放养约1029尾对虾较适宜。     

人工光型密闭式植物工厂的设计与环境控制

完全使用人工光源的密闭式植物工厂就是以最小限的物质、能源和资源消耗为前提实现适度环境控制的系统，可用来进行高品质种苗生产。研究利用不透光的绝热材料在中国农业大学建成了2套示范型密闭式植物工厂，利用与植物光合吸收光谱特性近似的荧光灯作为人工光照源、层流循环送回风及粗效/高效过滤有效地调控植物生产空间的物理环境和洁净度。经过两年的实际运行表明该密闭式植物工厂的空气洁净度达到了国家标准M7级。面积为15 m²的组织培养间在荧光灯的光照度分别为(47±8)，(67±12)和(113±21)μmol/m²/s时，控制点的温度变化分别为(25.4±0.5)，(25.3±0.7)和(25.5±0.7)℃，相对湿度变化分别为(63±4)%，(65±6)%和(63±7)%，CO₂浓度变化为(803±13)μL/L。因此，该人工光型密闭式植物工厂作为一种清洁高效的新型生产模式能够达到适度的环境控制和较高的洁净度，且植物生产空间的环境差异较小，适用于高品质种苗和高附加价值的药草或香料植物的大规模生产。     

多环境参数控制的猪养殖箱设计及箱内气流场分析

在规模化养殖中猪舍环境日益重要的背景下,为了便于研究猪舍内不同环境对猪健康的影响,该文设计了基于多环境参数控制的猪养殖箱。养殖箱采用气流自循环的通风模式,通过ANSYS对该养殖试验箱的气流场走向、模式以及风速适宜性进行模拟仿真。该养殖箱利用环境因子检测模块中的传感器集成节点和激光NH_3传感器实时获取养殖箱内的温度、相对湿度、NH_3浓度、CO_2浓度、风速等环境数据,并通过通信中转节点STM32发送至主控制器可编程逻辑控制器(programmable logical controller,PLC),PLC对环境数据进行处理,并根据已处理的环境数据进行环境调控,实现箱内环境的自动控制。与此同时,PLC将环境数据上发至上位机PC,通过WinCC监控软件实现了环境数据动态显示,通过VB脚本实现了历史数据自动定时导出至Excel文件功能。养殖箱气流烟雾试验、空箱试验以及保育猪养殖试验结果表明:养殖箱内气流走向形成大循环,且通风无死角,养殖箱环境控制系统的温度控制精度为±1℃,相对湿度可以控制在50%～80%的适宜范围内,NH_3浓度控制精度小于±3í10-6,CO_2浓度可以控制在1540í10-6以下,养殖箱能够在较长时间稳定运行的同时,实现了箱内温度、相对湿度、NH_3浓度、CO_2浓度等环境因子精确控制,为不同环境的养殖试验提供试验平台。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分，因此，各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中，在细菌、真菌中已经对氮素营养信号有了较好的研究，而植物中则相对缓慢，但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成，以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

Aircraft operations near concentrations of birds in Antarctica: The development of practical guidelines

Aircraft operations have the potential to disturb and to impact negatively on bird life. A gradient of increasing behavioural response is evident in birds when exposed to increasing aircraft stimulus. The most major disturbance is likely to lead to impacts on the health, breeding performance and survival of individual birds, and perhaps bird colonies. A process of revision to policies on aircraft operations contained in management plans for a number of specially protected areas in Antarctica by the United Kingdom, accompanied by consultations made within the scientific community through the Scientific Committee on Antarctic Research (SCAR) and with operational interests through the Council of Managers of National Antarctic Programmes (COMNAP) resulted in new guidelines being adopted by the Antarctic Treaty Consultative Parties in June 2004. The principal recommendations of the guidelines are that bird colonies should not be overflown below 2000 ft (∼610 m) above ground level and landings within 1/2 nautical mile (∼930 m) of bird colonies should be avoided wherever possible. These guidelines are less stringent and less specific than those that were recommended by the SCAR specialist group on birds, and represent a compromise to accommodate operational needs. While the adoption of clear and consistent guidelines for the operation of aircraft in Antarctica is welcome in that this provides practical advice that is likely to reduce incidences of close aircraft/bird encounters, there remains insufficient knowledge of the interactions between aircraft and birds in Antarctica, and the consequent impacts on individual birds and on bird populations. It is important, therefore, that the guidelines adopted are considered interim, and should be kept under scrutiny with revisions made as new and improved research results appear.     

The abundance of heterocystous blue-green algae in rice soils and inocula used for application in rice fields

Summary Algal populations were quantified (as colony-forming units [CFU] per square centimetre) in 102 samples of rice soils from the Philippines, India, Malaysia and Portugal, and in 22 samples of soil-based inocula from four countries. Heterocystous blue-green algae (BGA) were present in all samples. Nostoc was the dominant genus in most samples, followed by Anabaena and Calothrix. In soils, heterocystous BGA occurred at densities ranging from 1.0 × 10² to 8.0 × 10⁶ CFU/cm² (median 6.4 × 10⁴) and comprised, on average, 9% of the total CFU of algae. Their abundance was positively correlated with the pH and the available P content of the soils. In soil-based inocula, heterocystous BGA occurred at densities ranging from 4.6 × 10⁴ to 2.8 × 10⁷ CFU/g dw (dry weight), comprising only a moderate fraction (average 13%) of the total algae. In most soils, the density of indigenous N₂-fixing BGA was usually higher than that attained by applying recommended rates of soil-based inoculum. Whereas research on the practical utilization of BGA has been mostly directed towards inoculation with foreign strains, our results suggest that attention should also be given to agricultural practices that enhance the growth of indigenous strains already adapted to local environmental conditions.Maître de Recherches ORSTOM (France), Visiting Scientist at IRRI