Effects of Enhanced Ultraviolet Radiation-B on Maize in Arid Regions of Middle-high Elevation

[Objective] The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B on maize and providing scientific reference to make proper countermeasures. [ Method] The location test in field and lift lamp of UV-B were used to observe the changes of maize height, leaf area and number of green leaves under influences of different UV-B radiation. [ Result] In arid regions of middle-high elevation, enhanced ultraviolet radiation-B could dwarf maize plant, decrease leaf area, decline number of green leaves and yield. The reason of decreasing leaf area was that enhanced ultraviolet radiation-B shortened leaf length and leaf width while the reason of declining yield was that yield components were all negatively influ- enced and with the increase of ultraviolet radiation-B, the yield declined dramatically. [ Concluslonl The result of this experiment would be good for maize production in arid regions of middle-high elevation.

Effects of a New Long-term Controlled-release Fertilizer on Growth and Development and Yield of Summer Maize

[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fertilizers were applied once at sowing summer maize to explore effects on maize growth, yield, economic profits and environment. [Result] Maize yield reduced a little in the treatment group with 60% CRF, and increased in varying degrees in the rest groups in the range of 1.1%-7.4%, and some showed significant differences. [Conclusion] Controlled-release fertilizers can be applied once at the amount of 80% common fertilizer＇s, with con- sideration of maize yield, nitrogen use rate and economic profits, which is beneficial for summer maize application and promotion in North China.

Effects of Pyrene Stress on Growth and Physiological Indexes of Maize(Zea mays L.) Seedling

[Objective]The paper was to explore the effects of pyrene stress on growth and physiological indexes of maize seedling.[Method] The effects of different concentrations of pyrene（0,0.5,1.0,and 2.0 mg/L） on growth and several physiological indexes,such as chlorophyll content,malnodiadehyde（MDA） content of both leaves and roots of maize（Zea Mays L.） seedlings of Shixiang 1（sensitive variety） and Guangtian 3（tolerant variety） were studied by a hydroponic experiment.[Result]As the concentration of prene increasing within the test concentration range,the contents of chlorophyll a and chlorophyll b in Shixiang 1 first increased and then decreased;relative growth yield and absolute growth rate showed the decreasing trend;MDA contents in roots and leaves showed the increasing trend.Relative growth yield,absolute growth rate and chlorophyll a content in Guangtian 3 first increased and then decreased;chlorophyll b and MDA contents in roots showed the increasing trend;MDA contents in leaves showed the decreasing trend.Compared with control,chlorophyll a and chlorophyll b contents of Shixiang 1 significantly increased under pyrene concentration of 0.5-1.0 mg/L,which significantly decreased as the concentration of pyrene ≥2.0 mg/L;MDA contents in roots and leaves significantly increased as the concentration of pyrene ≥1.0 mg/L,while relative growth yield and absolute growth rate significantly decreased.Chlorophyll a and chlorophyll b contents in Guangtian 3 significantly increased as the concentration of pyrene ≥1.0 mg/L.Pyrene concentration had significantly negative correlation with relative growth yield and absolute growth rate of Shixiang 1,while it had significant positive correlation with MDA contents in roots.Pyrene concentration had significant positive correlation with chlorophyll b and MDA contents in roots of tolerant variety Guangtian 3.[Conclusion]The study provided basis for the management measures of maize during its seedling stage.

Research on the Dynamic Simulation System of Maize Growth

Dynamic simulation system of maize growth is developed by the physiological and ecological model,morphological structure model,computer science and virtual reality technology,to improve the level of precise operation of maize production.The computer graphics algorithms,virtual reality technology,animation design and information integration technology are applied to maize production by this system.establishment of dynamic simulation system of maize growth is conducive to raise level of precise operation in maize production.The system also can assist the relevant production research and testing,to reduce cost and improve efficiency.

鲁迅先生的教学语言

鲁迅先生讲课,无论是在杭州、北平,还是在厦门、广州,都得到学生的热烈欢迎和赞扬。“每次每次,当鲁迅先生仰着冷静的苍白的面孔,走进北大的教室时,教室里两人一排的座位上总是挤坐着四五个人,连门边、连走道都站满了校内的和校外的、正式的和非正式的学生。”在厦大、中大呢,轮到鲁迅先生讲课,不仅是文科学生早就提前坐进课堂。

禅诗今译二首

赠别大慧宗果桶底脱时大地阔, 命根断处碧潭清。好像一点红炉雪, 散作人间照夜灯。

Nutrient Content in Soils and Adaptability of Corn in Yuanzhou District,Guyuan City

[Objective] The aim was to research rational fertilization of corn in Yuanzhou District, Guyuan, Ningxia Hui Autonomous Region. [Method] Nutrient con- tents in soils in Yuanzhou District were measured with conventional analysis method and the suitable fertilization scheme of corn growth was proposed based on fertiliz- er-application rule of corn growth and nutrient balance. [Result] Soil in farmlands in Yuanzhou District was of alkalinity; organic matter, N, P and Zn were shortage; S was extremely insufficient; Fe and Mn were moderate; K was abundant; Cu would satisfy crop growth, [Conclusion] The research provides references for yield increase, reduction of chemical fertilizer and related pollution for corn growth.

Steel Slag as an Iron Fertilizer for Corn Growth and Soil Improvement in a Pot Experiment

The feasibility of steel slag used as an iron fertilizer was studied in a pot experiment with corn. Slag alone or acidified slag was added to two Fe-deficient calcareous soils at different rates. Results showed that moderate rates (10 and 20 g kg-1) of slag or acidified slag substantially increased corn dry matter yield and Fe uptake. Application of steel slag increased the residual concentration of ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA) extractable Fe in the soils. The increase of extractable Fe was usually proportional to the application rate, and enhanced by the acidification of slag. Steel slag appeared to be a promising and inexpensive source of Fe to alleviate crop Fe chlorosis in Fe-deficient calcareous soils.

Losses of Urea-Nitrogen Applied to Maize Grown on a Calcareous Fluvo-Aquic Soil in North China Plain

Field experiments were conducted in a maize (Zea mays L.)field of a calcareous fluvo-aquic soil in North China Plain for studying the fate and ammonia loss of urea-N applied at seedling stage,as well as the effectiveness of coated calcium carbide(CCC) in reducing N loss and in improving the yield efficiency of urea.Results show that:(1) For the surface-broadcast treatment ammonia volatilization (measured with micro-meteorological technique)took place quickly,reached the peak 20-26hr after application,and then declined gradually;the cumulative ammonia loss approached the maximum 188hr after application (30% of the N applied),and increased only to 32% 284 hr after application;the latter accounted for 71% of the total loss (45% of applied N).(2) In the case of point placement at a depth of 5-10 cm,ammonia loss 188hr after application was only 12% of the N applied,accounting for 40% of the total loss.(3) There was no difference in total loss between the application depths of 6cm and 10 cm,the loss of them was 30% and 29%,respectively.(4) Total loss of N applied at lower rate (40kg N/ha)with point deep placement at 6cm depth was found only 4% of the N applied,it rose up to 30% when the rate of application increased to 80kg N/ ha.(5) The nitrification inhibitor,CCC,seemed to enhance N loss of urea rather than reduce it,and did not show any benefit effect in improving the yield efficiency of urea,which is presumably due to the high potential of ammonia volatilization in the soil and climatic conditions under investigation.

Effect of Ammonium Polyphosphate on Plant Growth Development and Absorption of Phosphorus and Zinc in Corn Seedlings

Using pot experiment to study the effect of new fertilizer ammonium polyphosphate on plant growth and uptake of phosphorus and zinc in corn seedlings. The results showed that under the conditions of equal phosphate fertilizer application, ammonium polyphosphate added to phosphate fertilizer could significantly improve the plant height and stem diameter of corn seedlings after sowed for 60 days, while improved biomass of corn overground part and roots and root shoot ratio. When the ratio of ammonium polyphosphate and diammonium phosphate was 2：1 （available phosphorus ratio）, the effect was the best. Ammonium polyphosphate had little effect on the phosphorus content of overground part of corn seedlings, but increased the phosphorus cumulant. In addition, ammonium polyphosphate applica- tion significantly improved the zinc concentration and zinc cumulant of corn over- ground part and roots. The results showed that ammonium polyphosphate had bet- ter bioavailability, meanwhile promoted the absorption of microelement zinc in crops.

Effects of Different Herbicides on Maize Growth and Weed Control in Maize Fields

Effects of four herbicides(paraquat, acetochlor, nicosulfuron and atrazine) on the growth of maize and control effect of plant quantity and fresh weight of weeds were studied. The results showed that 15 days after spraying the herbicides on weeds,the prevention and control effect of paraquat on weeds was the optimum, and its effects on the plant quantity and fresh weight of weeds were above 81.57%; the prevention and control effect of acetochlor on weeds was the second best; the prevention and control effect of atrazine on weeds was the worst, and its effects on the plant quantity and fresh weight of weeds were only 51.04% and 37.86%. After 30 or 45 days, the prevention and control effect of atrazine and nicosulfuron on weeds in the maize fields was better than the other herbicides, and their effects on the plant quantity and fresh weight of weeds were higher than 70.00% and 85.00%. Acetochlor and paraquat had certain phytotoxicity to the growth of maize after about 15 days, and its leaves became yellow and grew slowly. On the whole, nicosulfuron had good prevention and control effect on weeds and had no phytotoxicity to the growth of maize.

Coupled Effects of Soil Water and Nutrients on Growth and Yields of Maize Plants in a Semi-Arid Region

Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.

Corn Growth as Affected by Plastic Cover Under Drip Irrigation Condition in the Desert

Plastic cover as a method to minimize soil water evaporation and improve water use efficiency, was used for corn during the whole growing period in a desert area. Field studies were conducted to determine the effect of plastic covering management on corn growth and rooting pattern and its relationship with changes in climate. Four treatments, 0) bared soil without cover) 1) covering one side of the crop, 2) covering both sides of the crop, and 3) covering the surface totally, were established on a sandy loam soil. Results showed that treatment 0 was significantly different from others and revealed that plastic covering was not always good to corn growth. Improper usage of plastic cover might weaken root development and thereafter lower the total yield of the crop. Suitable practices combining different methods discussed could not only improve water use efficiency but also increase the crop yield.

Effects of Dietary Corn Gluten Meal on Growth Performance and Protein Metabolism in Relation to IGF-I and TOR Gene Expression of Juvenile Cobia (Rachycentron canadum)

A growth experiment was conducted on cobia(Rachycentron canadum,initial weight 108.2 g ± 3.0 g) to investigate the effects of dietary corn gluten meal(CGM) levels on the fish growth,whole body composition and protein metabolism in relation to specific gene expression.Five isonitrogenous(crude protein 45%) and isoenergetic(gross energy 20 kJ g 1) practical diets were formulated by replacing 0%(the control),17.5%,35.0%,52.5%,and 70.0% of fish meal(FM) protein with CGM protein.No significant differences were observed in the survival,feed intake(FI),specific growth rate(SGR),feed efficiency(FE) and protein productive value(PPV) among fish fed diets with 0%,17.5%,35.0%,and 52.5% of CGM protein.However,these indices were significantly lower in fish fed the diet with 70.0% of CGM protein than those in fish fed the control diet(P < 0.05).The whole-body crude protein and lipid contents were significantly lower while the whole-body moisture content was significantly higher in fish fed the diet with 70.0% of CGM protein compared with the control group(P < 0.05).When 70.0% of FM protein was replaced by CGM,plasma total protein and cholesterol contents were significantly lower than those in the control group(P < 0.05).Fish fed the diet with 70.0% of CGM protein had significantly lower hepatic insulin-like growth factor I(IGF-I) expression levels than those in the control group(P < 0.05).However,no significant differences were observed in hepatic target of rapamycin(TOR),dorsal muscle IGF-I and TOR expression levels among dietary treatments.Results of the present study indicated that 52.5% of FM protein could be replaced by CGM in the diets without significant influences on the growth,feed utilization and protein metabolism of juvenile cobia.The present results might be useful for developing cost effective and sustainable cobia dietary formulations.

Fate of Fertilizer Nitrogen Applied to Crops Grown on Fluvo-Aquic Soil in Huang-Huai-Hai Plain

The fate of urea-and ammonium bicarbonate (ABC)-nitrogen (N) applied by prevailing traditional techniques to winter wheat (Triticum aestivum L.) or maize (Zea mays L.) grown in the fields of Fluvo-aquic soil was investigated using 15N tracer-micro-plot technique. Results show that:(1) at maturity of wheat, N recovery in plants and N losses of urea and ABC applied at seeding in autumn were 31-39%, and 34-46%, respectively, while the corresponding figures for side-banding at 10 cm depth in early spring were 51-57%, and 5-12%; surface-broadcast of urea followed by irrigation at early spring was as efficient as the side-banding in improving N recovery in plants and reducing N loss, however, such technique was found less satisfactory with ABC. (2) At the maturity of maize, N recovery in the plants and N loss of urea and ABC sidebanded at seedling stage or prior to tasseling ranged from 23% to 57%, and 9% to 26%, respectively. (3) Either in Wheat or in maize experiment, the majority of residual fertilizer N in soil profile (0-60 cm) was in the form of biologically immobilized organic N, however, the contribution of ammonium fixation by clay minerals increased markedly with depth in soil profile. (4) Though the proportion of residual fertilizer N was generally highest in the top 20 cm soil layer, considerable reaidual N (mostly 6-11 % of the N applied) was found in 60-100 cm soil layers.

Review of Factors Affecting the Yield and Quality of Corn Silage

Corn silage is the most popular and important source of energy and fber for ruminants. Much research focused on the chopping length, additives, sealing system, harmful bacteria and their toxins, and so forth, has been done on corn silage both at home in China and abroad. Some suggestions were presented in this review： （1） Corn silage modulation： Whole-plant corn harvested at the milk-ripe stage with a dry matter （DM） content of 30%~40% was selected as silage material and treated by rubbing and cutting. In the process of silage, commercial Lactobacillus buchneri was inoculated, exogenous protease added appropriately, cellulose enzyme added depending on the phenological period, the silage container and the species of the animals, and coextruded polyethylene？polyamide oxygen barrier flm （OB） selected as the seal material. （2） Strengthening management： Aerobic exposure should be avoided at the storage stage and reduced during the feeding phase. The proportion of corn silage was increased depending on the type of animal and their management. （3） Suggestions for further research： Further studies would be needed for the effects of liquid and solid wastes on soil, water and vegetation, and the treatment of these wastes.

Effects of Intercropping with Weeds on Growth and Zinc Uptake by Fruit Maize Seedlings

A pot experiment was conducted to study the effects of intercropping with Echinochloacrusgali, Polygonumorientale, Conyzacanadensis and Senecioscan-dens on growth and zinc uptake of fruit maize seedlings. The results showed that intercropping with E. crusgali_and C. canadensis increased root, stem and sheath, leaf and aboveground part biomasses of fruit maize seedlings, increased above-ground part biomasses of fruit maize seedlings by 58.89% and 8.76%, respectively;but intercropping with P. orientale and S. scandens decreased the biomass of fruit maize seedlings. Compared with monoculture, intercropping with E. crusgali_and C. canadensis also enhanced the chlorophyl and carotenoid contents of fruit maize seedlings, and intercropping with P. orientale_and S. scandens decreased them. On zinc uptake, intercropping with E. crusgali_and C. canadensis_enhanced the zinc contents in roots, stems and sheaths, leaves and aboveground part of fruit maize seedlings, enhanced by 1.24% and 3.89% in aboveground part; intercropping with P. orientale_and S. scandens decreased zinc contents in fruit maize seedlings. There-fore, intercropping with E. crusgali_and C. canadensis could promote the growth and zinc uptake of fruit maize seedlings.

Influence of Seed Coating Formulations on Maize Production

Effects of four coating formulations on maize production were studied.The results showed that all coating formulations had some effects on improving maize seedlings,strengthening the resistance againt diseases and pests and increasing the yields in different degrees,especially Paxil which increased the corn yield by 12.0%,significantly higher than the control.

Growth Parameters of DK8031 Maize Variety as Affected by Varying Irrigation and Nitrogen Fertilizer Rates in Embu County, Kenya

Determination of crop growth parameters of maize helps assess the performance of the crop for food security. A study was conducted in two seasons covering 2012 and 2013 to establish optimal irrigation and nitrogen fertilizer rates for drought tolerant hybrid maize （Zea mays L.）, DK8031 variety, in sandy loam soils using furrow irrigation. Four additive irrigation levels （119.05 mm, 238.10 mm, 357.15 mm and 476.2 mm） were allocated the main plots while five nitrogen fertilizer rates （0 kg/ha, 60, 75 kg/ha, 90 kg/ha and 100 kg/ha） were allocated the sub-plots. Both irrigation and nitrogen fertilizer treatments significantly enhanced crop growth parameters under consideration. Stand count per treatment plot, plant height and number of leaves per ranged from 45-59 plants/plot, 215-238 cm and 14-16 leaves respectively. It was concluded that use of supplementary irrigation and phased nitrogen fertilizer rates for maize growing in areas such as Embu can greatly promote crop growth.

Dicamba Growth Regulator Promotes Genotype Independent Somatic Embryogenesis from Immature Zygotic Embryos of Tropical Maize Inbred Lines

Maize is one of the most important cereal crops in Sub-Saharan Africa and an important source of energy for humans. However, the difference in the dedifferentiation frequency of immature embryos among various genotypes indicates that callus induction and genetic transformation is dependent on the genotype. This phenomenon is an impediment in the fundamental process of improving tropical maize germplasm especially through genetic engineering. Here, five tropical maize （Zea mays L.） genotypes, CML 216, CML 144, A 04, E 04 and TL 21, were evaluated for callus induction on MS medium supplemented with the growth regulator dicamba. Embryogenic and non embryogenic callus induction was independent ofgenotype when young immature embryos, 12 days after pollination （DAP） were used for tissue culture in combination with dicamba. The optimal concentration of dicamba for induction ofembryogenic callus in all the genotypes was 3 mg/L, which was also the concentration at which non embryogenic callus formation was lowest. The frequency of embryogenic callus induction ranged from 35% to 79% among the five genotypes and somatic embryos regenerated R0 shoots that produced normal R1 progenies. This regeneration method is expected to facilitate the development of a more efficient genotype independent Agrobacterium- mediated transformation system for tropical inbred lines.