新型稀有元素微肥研制配方的肥效试验

对洛阳市农科所新技术开发公司研制的4个不同配方的新型稀有元素微肥在莲豆上进行了肥效试验，结果表明：Ⅱ^#配方的微肥产品，对莲豆的营养生长和生殖生长均有十分显著的促进作用，不但可以促进莲豆的生长发育，而且可以大幅度地提高莲豆的英果产量，是施用于英果类蔬菜作物营养平衡、肥效较好的最佳配方；Ⅱ^#微肥还可能更广泛地适用于以营养体为收获对象的茎叶类蔬菜作物，在高效多功能生态农业微肥新产品的研制开发方面具有较高的利用价值和广阔的应用前景。     

Does root-sourced ABA play a role for regulation of stomata under drought in quinoa (Chenopodium quinoa Willd.)

The Andean seed crop quinoa (Chenopodium quinoa Willd.) is traditionally grown under drought and other adverse conditions that constrain crop production in the Andes, and it is regarded as having considerable tolerance to soil drying. The objective of this research was to study how chemical and hydraulic signalling from the root system controlled gas exchange in a drying soil in quinoa. It was observed that during soil drying, relative g_s and photosynthesis A_max (drought stressed/fully watered plants) equalled 1, until the fraction of transpirable soil water (FTSW) decreased to 0.82 ± 0.152 and 0.33 ± 0.061, respectively, at bud formation, indicating that photosynthesis was maintained after stomata closure. The relationship between relative g_s and relative A_max at bud formation was represented by a logarithmic function (r² = 0.79), which resulted in a photosynthetic water use efficiency WUE_Amax_/gs$\text{WU}{\text{E}}_{A_{\text{max}}/g_{\text{s}}}$ of 1 when FTSW > 0.8, and increased by 50% with soil drying to FTSW 0.7–0.4. Mild soil drying slightly increased ABA in the xylem. It is concluded that during soil drying, quinoa plants have a sensitive stomatal closure, by which the plants are able to maintain leaf water potential (ψ_l) and A_max, resulting in an increase of WUE. Root originated ABA plays a role in stomata performance during soil drying. ABA regulation seems to be one of the mechanisms utilised by quinoa when facing drought inducing decrease of turgor of stomata guard cells.     

Community structure and carbon and nitrogen storage of sagebrush desert under grazing exclusion in Northwest China

Overgrazing is regarded as one of the key factors of vegetation and soil degradation in the arid and semi-arid regions of Northwest China.Grazing exclusion(GE)is one of the most common pathways used to restore degraded grasslands and to improve their ecosystem services.Nevertheless,there are still significant controversies concerning GE’s effects on grassland diversity as well as carbon(C)and nitrogen(N)storage.It remains poorly understood in the arid desert regions,whilst being essential for the sustainable use of grassland resources.To assess the effects of GE on community characteristics and C and N storage of desert plant community in the arid desert regions,we investigated the community structure and plant biomass,as well as C and N storage of plants and soil(0-100 cm depth)in short-term GE(three years)plots and adjacent long-term freely grazing(FG)plots in the areas of sagebrush desert in Northwest China,which are important both for spring-autumn seasonal pasture and for ecological conservation.Our findings indicated that GE was beneficial to the average height,coverage and aboveground biomass(including stems,leaves and inflorescences,and litter)of desert plant community,to the species richness and importance values of subshrubs and perennial herbs,and to the biomass C and N storage of aboveground parts(P<0.05).However,GE was not beneficial to the importance values of annual herbs,root/shoot ratio and total N concentration in the 0-5 and 5-10 cm soil layers(P<0.05).Additionally,the plant density,belowground biomass,and soil organic C concentration and C storage in the 0-100 cm soil layer could not be significantly changed by short-term GE(three years).The results suggest that,although GE was not beneficial for C sequestration in the sagebrush desert ecosystem,it is an effective strategy for improving productivity,diversity,and C and N storage of plants.As a result,GE can be used to rehabilitate degraded grasslands in the arid desert regions of Northwest China.     

大豆和玉米光合速率、光能利用率对光强响应特征的差异性分析

用Michaelis-Menten方程和Dagneli方程对东北地区大豆和玉米各个生育时期光合速率、光能利用率对光强的响应特征进行了模拟研究。结果表明,两种方程均能很好地描述大豆和玉米叶片光合速率对光强的响应特征,两种方程的模拟效果是一致的,但两种方程得到的参数存在极显著差异,用Michaelis-Menten方程模拟得到的表观初始量子效率、表观最大光合速率、表观暗呼吸速率极显著大于用Dagneli方程得到的参数。但用Dagneli方程模拟得到的表观最大光合速率更接近实际,而用Michaelis-Menten方程得到的表观暗呼吸速率更接近实际。但无论用哪种方程模拟,在各个生育时期玉米的表观初始量子效率、表观最大光合速率和光能利用率均极显著高于大豆。光能利用率随着光强的增大先增大而后降低,当光强在0￣2000μmol/(m2·s)之间时,大豆的平均光能利用率为0.0185mol/mol,玉米为0.0281mol/mol。光能利用率在各个生育期有一定的变异,大豆和玉米均表现出在生育前期相对较低,中期升高,后期又降低的规律。在整个生育期,玉米的光能利用率约为大豆的1.6倍。     

谈交流电动机的恒功率因数控制

对交流电动机的功率因数进行负反馈控制可使其功率因数恒定。通过对交流电动机稳态数学模型的分析可知,最优效率对应的功率因数由转差频率控制,且电动机功率因数在小范围内变化时所引起效率变化小。因此,可以用恒功率因数控制替代最优功率因数控制。     

农业联合数字图书馆建设初探

作者在简要叙述了数字图书馆概念的基础上，着重对国外数字图书馆的建设模式与特点，我国在数字图书馆建设中值得注意的问题，以及农业联合数字图书馆建设的主要思路进行了探讨。     

用 1/N 展开法研究钨的能谱

用玻色子1／N展开技术研究了6个钨同位素的能谱和约化电磁跃迁概率B(E2)．结果表明，展开式的高阶项十分重要，6个核的能级能量的理论值和实验值的方均根差，最大的是154keV，最小的只有11keV，符合得令人满意．而且理论能正确地符合实验方面跃迁概率的“回弯”现象．     

Wood, nematodes, and the nematode-trapping fungus Arthrobotrys oligospora

Researchers have proposed that Arthrobotrys oligospora and related fungi trap soil nematodes to obtain nitrogen and thereby compete saprophytically for carbon and energy in nitrogen-poor environments, including litter and wood. The current study tested two hypotheses concerning this model. The first was that wood decomposition would be enhanced if both large numbers of nematodes (a potential nitrogen supply) and A. oligospora (a cellulolytic organism that can use that N supply) were present. The second was that A. oligospora trapping activity would increase if large numbers of nematodes were added to soil containing abundant carbon (a wood dowel or chip). Although the first hypothesis was supported by an in vitro experiment on agar (A. oligospora degraded much more wood when nematodes were present), neither hypothesis was supported by an experiment in vials containing field soil. In soil, wood decomposition was unaffected by the addition of A. oligospora or large numbers of nematodes. Whereas A. oligospora trapped virtually all nematodes added to agar cultures, it trapped few or no nematodes added to soil. Given that the fungal isolate was obtained from the same soil and that the fungus increased to large numbers (>1×10³ propagules g⁻¹ soil), the failure of A. oligospora to trap nematodes in soil is difficult to explain. Soil nitrate levels, however, were high (71 mg kg⁻¹), and it is possible that with lower nitrate levels, trapping in soil might be stimulated by wood and nematodes.     

菌糠在兔饲料中的应用效果研究

本研究分冬季（全喂饲合饲料）和夏季（增喂一定量的青草）两次试验，每次试验选用比利时兔和日本大耳白兔各３６只，将菌糠以１０％和２０％的比例添加于饲料中，探讨了菌糠对兔的增重、产肉性能等的影响。结果表明，饲料中添加１０％的菌糠，在增重、料肉比、屠宰率和经济效益等方面与对照组无显著差异，添加２０％的菌糠有不良影响。同时还表明，比利时兔比大耳白兔能更好地利用菌糠，在冬季全喂配合饲料时能获得较好的饲养效果。     

浅谈乡镇农机管理站效能建设的有效运行机制

本文通过提高认识、建立有效机制、发挥激励作用三个方面，阐述了乡镇农机站效能建设措施，重点是建立11项制度。