Growth and ecological impacts of traditional agroforestry tree species in Central Himalaya, India

A number of multipurpose tree species are conserved as scattered trees in settled farms on terraced slopes by the traditional farmers in Central Himalaya, India. Knowledge on growth rates and ecological impacts of these tree species is limited. Ten locally valued multipurpose tree species, viz., Albizzia lebbek, Alnus nepalensis, Boehmeria rugulosa, Celtis australis, Dalbergia sissoo, Ficus glomerata, Grewia optiva, Prunus cerasoides, Pyrus pashia and Sapium sebiferum, were established as mixed plantations at a degraded community forest land site and an abandoned agricultural land site in a village at 1200 m altitude in District Chamoli, India. At the abandoned agricultural land site, annual food crops were grown, along with planted trees, providing supplemental irrigation and organic manure following traditional farming practices. Survival, height, stem circumference, crown depth and width, number of branches, above-ground biomass and soil physico-chemical characteristics were monitored up to five years of plantation growth. Above-ground tree biomass accumulation at the abandoned agricultural land site was 3.9 t ha⁻¹ yr⁻¹ compared with 1.1 t ha⁻¹ yr⁻¹at the degraded forest land site. B. rugulosa, C. australis, F. glomerata, G. optiva, P. cerasoides and S. sebiferum showed more prominent differences in growth at the two sites compared with A. lebbek, A. nepalensis, D. sissoo and P. pashia. A. nepalensis and D. sissoo showed best growth performance at both the sites. A significant improvement in soil physico-chemical characteristics was observed after five years at both of the sites. Carbon sequestration in soil was higher than that in bole biomass. This revised version was published online in June 2006 with corrections to the Cover Date.     

Prevalence and molecular characterization of bovine Cryptosporidium isolates in India

A survey based on PCR assay of 18S SSU rRNA gene revealed a 30.2% infection with Cryptosporidium spp., out of 457 faecal samples collected from neonatal bovine calves across three different regions of India. The PCR-RFLP pattern of the gene in all the positive cases established the species as Cryptosporidium parvum. Highest prevalence was recorded in the monsoon months (37.3%) and in the calves showing acute diarrhoea (32.3%). The calves below 15 days of age were mostly affected (45.1%). The infection was more prevalent in the northern parts (35.4%) of the country than in the eastern or southern parts. Results indicated that C. parvum was the only species of Cryptosporidium prevalent in bovine calves in three different geographical regions of India.     

"热大99W"序列旱稻新品系农艺特征与抗旱特性的研究

海南山栏稻原种与水稻常规品种杂交,Ｆ２或Ｆ３单株再与水稻雄性不育恢复系杂交,其后代又与雄性不育系再杂交,在四交Ｆ６代进行单株选择,Ｆ７代进行株系选择,Ｆ８代对入选的９个品系进行农艺性状比较、产量构成分析和抗旱生理指标测验。结果表明其中３个品系具有良好的农蕊性状和较高的产量潜力（产量可超过４５００ｋｇ／ｈｍ＾２）,同时表现较强的抗旱性。从而获得兼备水稻理想株型和山栏稻抗旱性的丰产旱稻新品系,为进一步培育优良旱稻新品种奠定了重要基础,并对稻作抗旱育种的技术路线进行了有益的探讨。     

尾巨桉3-羟基-3-甲基戊二酰CoA还原酶基因的克隆及表达分析

尾巨桉(Eucalyptus urophylla×E.grandis)属于桃金娘科(Myrtaceae)桉属(Eucalyptus)速生树种之一,其油腺细胞能够产生1,8-桉叶素、B-桉叶醇和α-蒎烯等主要成分的挥发性精油.     

美国动物疫病防控体系建设的经验借鉴

美国是畜牧业生产大国,完备高效的动物疫病防控体系是重要保障。通过完善的法律法规、行政机构管理体系和财政支持,美国建立了执行高效的兽医制度体系和外来动物应急反应管理机制,从而有效地控制了动物疫病的发生和传播。在国家政府、地方政府、社会、养殖者等的共同协作下,形成了“可预防,可追溯,常监督,快反应”的动物疫病防控体系。学习和借鉴美国的有效经验,以期为中国动物疫病防控工作提供启示。     

Methylene Blue Stainability of Root-Tip Protoplasts as an Indicator of Aluminum Tolerance in a Wide Range of Plant Species, Cultivars and Lines

We previously developed a new simple technique of methylene blue (MB) staining for the discrimination of aluminum (Al)-tolerant protoplasts from 4 plant species (rice, oats, maize and pea). The objectives of the present study were to confirm the applicability of this technique to a wider range of plant species, cultivars and lines, and to identify a common strategy for the early stage of Al tolerance. A total of 10 plant species, two Brachiaria spp., two Oryza spp., buckwheat, maize, pea, triticale, wheat and barley, corresponding to 18 different plant samples (species, cultivars, and lines), were used. Al tolerance (relative net root elongation of the longest root), which was screened at 20 μM AICI₃ in 0.2 mM CaCl₂ (pH 4.9) for 24 h, ranged widely from 10 to 88. Among cultivars and lines within the same species, Al accumulation in the root tip portion was higher in Al-sensitive plants, corresponding to more severe permeabilization of the plasma membranes (PM). Protoplasts isolated mainly from the epidermis, and outer and central parts of the cortex were stained to different degrees by MB, and the blue color was observed both on the surface and inside the protoplasts. Color pictures obtained after staining for 3 min with 0.1% MB were analyzed by Image Hyper II. The ratio of the heavily stained area at threshold 95 to the entire area stained with MB at threshold 125 was defined as MB stainability. MB stainability was negatively correlated with Al tolerance ( y = 48.6e^{−0.02 x} , R ²= 0.676**) suggesting the common importance of permeation characteristics of PM, in addition to PM negativity for Al tolerance in a wide range of plant species, cultivars and lines. Analysis of the PM lipid composition was proposed as an important topic for future studies on the negativity and permeation of PM.     

Effect of deep tillage on dryland crop production in red soils of India

The red soils of the semi-arid tropics of Andhra Pradesh, India, are shallow, eroded and compact. The profile is anisotropic with a dense sub-surface layer. The average depth of the surface layer is 8.2 cm. The solum depth varies from 50 to 100 cm. The subsurface layer restricts the root proliferation of crops. A light wooden country plow is used by farmers for primary tillage. It penetrates on average to a depth of 15.5 cm with a coefficient of variation of 80%. To disturb the sub-surface layer to a greater extent a heavy-duty disc plow was used. This tilled to a depth of 23.3 cm, with a coefficient of variation of 29%, and reduced the bulk density. The infiltration and depth of penetration of the wetting front increased considerably with deep tillage.

The advantage of deep tillage to crop yields was found to be dependent on rainfall pattern and plant type. The interaction was between recharge in the profile and rooting depth. In a normal rainfall season the yield advantage was observed for both short duration (sorghum and pearl millet) and long duration (castor) crops, while the advantage in an above-normal rainfall season was restricted to long duration crops only. No yield advantage was noticed in a sub-normal rainfall year for any of the crops.

The residual effects of deep tillage were marginal. Therefore, by considering the historical rainfall data, it was observed that deep tillage was beneficial in 63 and 91% of years for short and long duration crops, respectively. Adoption of deep tillage every year in traditional castor—sorghum rotation resulted in benefits in 56% of years for both the crops. Since deep tillage requires a high monetary input, it is advisable to adopt this practice only for castor. This illustrates clearly the need for considering rainfall pattern and crop requirements to select an appropriate tillage practice under rainfed farming.     

Regulation of Nitrification by Benzotriazole,o-Nitrophenol,m-Nitroaniline and Dicyandiamide and Pattern of NH3 Emissions from Citronella Field Fertilized with Urea

Nitrification inhibitors areuseful for reducing fertilizer related environmentalpollution. Use of such nitrification inhibitors as,benzotriazole, o-nitrophenol, m-nitroaniline anddicyandiamide has effectively regulated nitrification in acitronella (Cymbopogon winterianus Jowitt.) fieldfertilized with urea. At 450 kg N ha^-1 yr^-1, there wassubstantially higher accumulation of NH⁺ ₄-N in thesoil. Proper placement (5 cm below soil surface) offertilizers have minimized NH₃ emissions even fromnitrification inhibitor treated urea plots. Thus, thenitrification inhibitors can potentially reduceenvironmental pollution connected to NO^- ₃ in soilwhile maintaining low NH₃ gas emissions, if thefertilizer is properly placed.     

Conjunctive use of saline and non-saline irrigation waters in semi-arid regions

In arid and semi-arid regions, effluent from sub-surface drainage systems is often saline and during the dry season its disposal poses an environmental problem. A field experiment was conducted from 1989 to 1992 using saline drainage water (EC=10.5–15.0 dS/m) together with fresh canal water (EC=0.4 dS/m) for irrigation during the dry winter season. The aim was to find if crop production would still be feasible and soil salinity would not be increased unacceptably by this practice. The experimental crops were a winter crop, wheat, and pearl-millet and sorghum, the rainy season crops, grown on a sandy loam soil. All crops were given a pre-plant irrigation with fresh canal water. Subsequently, the wheat crop was irrigated four times with different sequences of saline drainage water and canal water. The rainy season crops received no further irrigation as they were rainfed. Taking the wheat yield obtained with fresh canal water as the potential value (100%), the mean relative yield of wheat irrigated with only saline drainage water was 74%. Substitution of canal water at first post-plant irrigation and applying thereafter only saline drainage water, increased the yield to 84%. Cyclic irrigations with canal and drainage water in different treatments resulted in yields of 88% to 94% of the potential. Pearl-millet and sorghum yields decreased significantly where 3 or 4 post-plant irrigations were applied with saline drainage water to previous wheat crop, but cyclic irrigations did not cause yield reduction. The high salinity and sodicity of the drainage water increased the soil salinity and sodicity in the soil profile during the winter season, but these hazards were eliminated by the sub-surface drainage system during the ensuing monsoon periods. The results obtained provide a promising option for the use of poor quality drainage water in conjunction with fresh canal water without undue yield reduction and soil degradation. This will save the scarce canal water, reduce the drainage water disposal needs and associated environmental problems.     

基于STM32的智能温室无线监控系统设计

智能温室无线监控系统采用嵌入式技术,由温湿度模块、无线传输模块、电源模块及自动控制系统组成,以期农业与自动控制系统结合,采集温室的光照度、温湿度,实现串口软件实时监控并存储采集到的数据。该系统的应用营造了一个有利于温室作物生长的环境,提高了蔬菜产量、品质,且节省了大量的劳动力资源。