早熟芋艿平衡施肥技术研究

通过两年芋艿施肥田间试验,表明获得早熟芋艿高产、高效的施肥方案为N 448.5 kg/hm2,P2O552.5kg/hm2,K2O 180~270 kg/hm2,N-P2O5-K2O比例为1∶0.12∶0.40~0.60,并推荐有机无机复合肥与化肥配合施用,以获得更高的产量和效益。早熟芋艿生育期短,施用充足的氮肥才能保证芋艿在较短的生育期内获得较高的产量,芋艿还是一种喜钾作物,施用钾肥能明显促进芋艿高产;在土壤有效磷含量不足的情况下,施用磷肥能促进芋艿正常生长。     

宣威市紫色土辣椒氮磷钾肥配比试验研究

对紫色土辣椒氮、磷、钾适宜施用量研究表明，紫色土氮磷钾肥对辣椒产量的影响顺序是磷肥〉氮肥〉钾肥。磷是限制辣椒产量的主导因子。在施用菜籽饼肥600kg／hm^2，折N31．2kg／hm^2、P2O5 11.7kg／hm^2、K2O 8．1kg／hm^2的基础上，辣椒产量≥20400kg／hm^2的氮磷钾优化组合施肥范围：N=113．9～204．6kg／hm^2，P2O5=145．9～177．2kg／hm^2，K2O=49．3～153．8kg／hm^2，N：P2O5：K2O=1：0．87～1．28：0．43～0．75。建议氮、磷、钾肥适宜用量为：N159．2kg／hm^2，P2O5 161．5kg／hm^2，K2O 101．5kg／hm^2，N：P2O5：K2O=1：1．01：0．64，辣椒最高产量预测值为21961．5kg／hm^2，施肥利润5417．7元／hm^2，投产比1：5．00。适量的氮、磷、钾营养使得养分比例平衡，有利于增加辣椒收果数，提高鲜椒产量，从而增加效益。     

南安市丘陵旱地甘薯氮磷钾适宜配比的研究

通过在南安市丘陵旱地三种不同类型土壤上布置“3417”设计的平衡施肥田间肥料试验，验证NPK肥的施用效果，建立甘薯产量和施肥利润与N、P、K施用量的数学模型，得出在该条件下的甘薯适宜施肥量和比例。结果表明，甘薯施用NPK肥料均获得一定幅度的增产增值效果。获得最高产量的施肥量为154．3～173．6kg／hm^2N，44．4～75．3kg／hm^P2O5，193．1～245．3kg／hm^2K2O，N：P205：K2O=1：0．26～0．43：1．24～1．41；最佳经济施肥量为140．0～162．0kg／hm^2N，40．8～67．0kg／hm^2P2O5，199．8～227．3kg／hm^2K2O，N：P2O5：K2O=1：0．25～0．41：1．23～1．64。低产田土壤适当增施N肥，P、K比例可以低些，中高产田土壤P、K比例要高些。     

平衡施肥对马铃薯产量及品质的影响

通过平衡施肥对马铃薯产量和品质影响的研究，结果表明：在当地条件下，马铃薯最佳经济施肥量为N141．15kg／hm^2，P2O5104．55kg／hm^2，K2O198．90kg／hm^2，施用比例1：0．74：1．41，最佳产量31845．30kg／hm^2，施肥利润3306．90元／hm^2，投产比1：3．63。采用平衡施肥能增加马铃薯产量，降低薯块硝酸盐和还原糖含量，并能增加淀粉含量，从而提高马铃薯产品品质，增加效益。马铃薯硝酸盐含量随氮肥施用量增加而增加，施用磷钾肥能明显降低硝酸盐含量。我区马铃薯生产重金属污染均未超标，符合国家食品卫生标准。     

甘薯氮磷钾肥平衡施用效应分析

本文运用311-A拟饱和最优回归设计，在沿海赤砂土甘薯主产区设置晚薯施用氮磷钾肥料试验，模拟出甘薯薯块产量和施肥利润的氮磷钾肥料效应函数，通过极值判别均为典型函数，用边际分析寻优，获得甘薯薯块最高产量和最高施肥利润的优化施肥组合分别为：Zmax为Zl=N136．25kg／hm^2，Z2=P2O552．71kg／hm^2，Z3=K2O275．68kg／hm^2，薯块产量最高，y^max=39．214t／hm^2；Zopt为Zl=N117．09kg／hm^2，Z2=P2O546．24kg／hm^2，Z3=K2O247．01kg／hm^2，施肥利润最佳为π^opt=18298．99元／hm^2。     

新疆高产棉花的钾肥施用效果

研究表明，钾肥在新疆主要棉田土壤上施用，对高产棉花有显著的增产作用，增产效果南疆大于北疆。施钾可提高棉花的单铃重和单株铃数。在一定氮磷施用条件下，最高产量的施钾（K2O）量，南疆为133．3kg/hm^2，北疆为146．8kg/hm^2，本试验条件下获得棉花高产，其氮磷钾施用比例，南疆为N:P2O3：K2O＝1：0．50：0．48，北疆为N:P2O：K2O＝1：0．50：0．53。氯化钾和硫酸钾对高产棉花有相似的增产作用。     

蕹菜平衡施用氮磷钾肥料效应研究

采用“3414”最优回归设计方法，对蕹菜高优栽培氮磷钾肥料合理配施技术进行研究。结果表明，本试验条件下当N223．6、P2O5 50．0和K2O 97．5kg／hm^2，三要素比例为1：0．224：0．436时，蕹菜最高经济产量达31391．4kg／hm^2；当N215．7、P2O5 46．4和K2O9 0．0kg／hm^2，三要素比例为1：0．215：0．417时，蕹菜最佳施肥利润为36211．8元／hm^2，经济产量亦达31360．1kg／hm^2。在同等肥力下，蕹菜硝酸盐含量与施氮水平呈显著正相关；与施磷、钾水平呈极显著负相关。     

应用最优混合设计研究氮磷钾不同配比对甘蔗产量和产糖量的效应

应用“311—A”最优混合设计进行田间试验，研究氮肥、磷肥、钾肥用量不同配比对甘蔗产量和产糖量的效应，通过运用统计分析软件对试验结果进行回归分析，建立多项式回归模型，寻求出甘蔗蔗茎产量及其产糖量的氮肥、磷肥、钾肥最佳组合范围及其最佳配比用量方案。在供试条件下，对于甘蔗产量的氮、磷、钾肥料用量最佳组合范围方案为：N=268．6～312．2kg／hm^2，P2O5=130．7～141．3kg／hm^2，K2O=322．4～344．8kg／hm^2，N：P2O5：K2O=1：0．45～0．49：1．10～1．20，最高产量预测值为112．7t／hm^2；对于产糖量的最佳组合范围方案为：N=257．9～290．8kg／hm^2，P2O5=139．0～158．0kg/hm^2，K2O=325．3～350．6kg/hm^2，N：P2O5：K2O=1：0．54：1．20～1．26，最高产糖量预测值为16．3t／hm^2。对于产量的经济最佳施肥量方案为：N=311．7kg/hm^2，P2O5=140．8kg/hm^2，K2O=344．4kg/hm^2，N：P2O5：K2O=1：0．45：1．10；对于产糖量的经济最佳施肥量方案为：N=290．6kg／hm^2，P2O5=157．8kg／hm^2，K2O=350．4kg／hm^2，N：P2O5：K2O=1：0．54：1．21。     

氮、磷和钾营养对新海16长绒棉产量和品质的影响

氮肥、磷肥、钾肥N：P2O5：K2O=1：0．71：0．30并配合Zn、Mn、B微肥施用，经济施肥量为N189．3kg／hm2、P2O5134．4kg／hm^2、K2O57．2kg／hm^2，能显著促进棉花的生长发育和提高产量，比对照增产40％，对新海16纤维品质中的马克隆值影响显著，但对纤维综合品质影响不显著。     

钾锌锰配合施用对马铃薯产量和品质的影响

采用三因素二次回归通用旋转组合设计方法，研究了山西石灰性褐土上施用氯化钾、硫酸锌、硫酸锰对马铃薯产量和品质的影响。研究结果表明：钾、锌、锰肥的合理配合施用能使马铃薯产量明显提高，品质得到显著改善。在本试验条件下，马铃薯高产、优质高效的配方施肥方案是：氯化钾297．9～396．0kg／hm^2，硫酸锌69．70～109．1kg／hm^2，硫酸锰92．54～126．27kg／hm^2。钾、锌、锰肥配施可显著增加块茎中的淀粉、粗蛋白含量，降低NO3-N含量。     

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