Effects of Planting Density and Nitrogen Amount on Stalk Lodging-Resistance and Yield of Summer Maize in Sichuan Basin

[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high-yielding cultivation technique.[Method] A widely planted maize cultivar ＇Chengdan 30＇ was used as experimental material to study the effects of planting density and nitrogen amount on the stalk agronomic traits,stalk lodging-resistance mechanical characters,stalk breaking percentage and yield of maize.Experiment was arranged in a two-factor split plot design with three replicates.The planting density was the main factor with three density gradients（4.5×10^4,6.0×10^4 and 7.5×10^4 plants/hm^2） and the nitrogen amount was the second factor with two different levels of nitrogen content（300 and 375 kg/hm^2）.[Result] The stalk lodging-resistance and yield were affected by planting density significantly.The increase of planting density would result in an increase of internode length and decrease of internode diameter,dry matter weight of per unit stalk length,rind penetration strength and breaking resistance of 3rd and 4th basal internodes.When planting density increased from 6.0×10^4 plants/hm2 to 7.5×10^4 plants/hm^2,the stalk breaking percentage in the whole growing season increased by 17.17%,and the yield reduced by 17.58%.The interaction between planting density and nitrogen amount affected the stalk breaking percentage in the whole growing season and yield significantly.The treatment with planting density of 6.0×104 plants/hm^2 and nitrogen amount of 375 kg/hm^2 of pure N was an optimal combination,which may not only control the stalk breaking percentage of whole growing stage effectively,but also could obtain an optimum grain yield.[Conclusion] In Sichuan Basin,the appropriate planting density and nitrogen amount for summer maize were 6.0×10^4 plants/hm^2 and 375 kg/hm^2.

Effects of Planting Density, Duration of Disclosing Plastic Film and Nitrogen Fertilization on the Growth Dynamics of Rapeseed under No-tillage Cultivation

[ Objective] This study was to understend the optimized combination of planting density, duration of disclosing plastic film and nitrogen fertilization under no-tillage cultivation. [ Method] Quadratic polynomial regression and saturated D-optimal design were employed to investigate the effects of planting density, duration of disclosing plastic film and nitrogen fertilization on the dynamics growth of rapeseed under no-tillage cultivation.[ Result] Within the experimental range, the growth dynamics of no-tillage cultivated rapeseed assumed a rise-fall tend. For the effects to the growth dynamics of no-tillage cultivated rapeseed, nitrogen application amount was higher than planting density and duration of disclosing plastic film. The interaction effect between planting density and duration of disclosing plastic film was higher than that between nitrogen application amount and planting density, and between nitrogen application amount and duration of disclosing plastic film. [ Conclusion] The optimized combination of these factors for dynamic growth of rapeseed under no-tillage cultivation was determined to be： planting density of per hectare 154 925 individuals, duration of disclosing plastic film of 110 d, nitrogen application amount of 315 kg/hm^2.

Economic Evaluation on "Planting Three to Produce Four" High-yielding Project of Super Hybrid-rice in Hunan

The research conducted investigation and survey on 186 farm households in 2014 and carried out economic evaluation on ＂planting three to produce four＂ highyielding project of super hybrid rice. The results showed that the project of ＂planting three to produce four＂ performed significantly in terms of increasing yields and incomes. For example, per unit area yield of one-season late hybrid rice and middleseason hybrid rice proved the highest, and net income from middle-season rice in Longhui was the highest. It is obvious that to increase per unit yield is key for improving net incomes and to reduce machine fees and worker fees is crucial for decreasing fees.

Effects of Plant Spacing and Finger Sticking Area Settings for Machine Transplanting on Yield of Double-season Early Rice

The effects of rice transplanters＇ transplanting settings（plant spacing and finger sticking area） on rice yield were investigated in two early-season rice cultivars：hybrid rice cultivar（Zhuliangyou 819） and conventional rice cultivar（Zhongjiazao 17）.The results showed that,different transplanting settings resulted in different numbers of transplanted basic seedlings,and the rice yield was significantly correlated with the number of transplanted basic seedlings.The number of transplanted basic seedlings increased with the decrease of plant spacing and the increase of finger sticking area.The rate of lost hills of machine transplanting decreased with the increase of finger sticking area.The leaf area index and amount of dry matter accumulation were highly correlated with the number of transplanted basic seedlings.The average yield of the rice transplanted with a plant spacing of11.5 cm was higher than that with a plant spacing of 13.8 cm.In the field transplanted with the rice under the plant spacing of 13.8 cm,the rice yield increased with the increase of finger sticking area,and the finger sticking area of 2.23 cm2 showed the highest rice yield of 8 174.16 kg/hm2 of Zhuliangyou 819 and 7 925.54kg/hm2 of Zhongjiaozao17.In the field transplanted with the rice under the plant spacing of 11.5 cm,the rice yield was the highest with the finger sticking area of 1.83 cm2,and then decreased with the large finger sticking area.Under the plant spacing of 11.5 cm,the highest rice yields of Zhuliangyou 819 and Zhongjiaozao17 were 8 492.94 kg/hm2 and 8 000.23 kg/hm2,respectively.Therefore,the preferred machine transplanting settings for double-season early rice are a plant spacing of11.5 cm and a finger sticking area of 1.83 cm2,while the finger sticking area should be increased to 2.23 cm2 for conventional rice cultivars.

High-efficiency Planting Techniques of Five Crops a Year for Fresh Edible "Faba Bean/Spring Mazie+Soybean-Autumn Maize/Autumn Soybean"

The high-efficiency planting mode for five crops a year of fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ was introduced, and its yield and economic benefits were compared with the planting mode of three crops a year of ＂faba bean-spring maize/red bean＂. The results showed that the planting method for fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ was much easier to operate with the input-output ratio of about185.6%, and its yield and economic benefits were 2.09 and 1.83 times of that of the planting mode for three crops a year, significantly improving the agricultural yield and income of farmers. In addition, the cropping index of the planting mode for fresh edible fresh edible ＂faba bean/spring maize ＋soybean-autumn maize/autumn soybean＂ reached up to 350%, and planting faba bean once a year and soybean twice a year could make the biological fixation amount of nitrogen increase 350-450kg/m^2, which equaled to up to 700 kg/m^2 of urea, showing significant ecological and social benefits. Based on the comparison results, the high-yield culture techniques of the planting mode of fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ were summarized.

Suitable Region for Flue-cured Tobacco (Nicotiana glauca L.) Planting Based on Spatial Scene Similarity

[Objective] The aim was to establish a model based on spatial scene similarity, for which soil, slope, transport, water conservancy, light, social economic factors in suitable planting areas were all considered. A new suitable planting area of flue-cured tobacco was determined by comparison and analysis, with consideration of excellent area. [Method] Totaling thirty natural factors were chosen, which were clas- sified into nine categories, from Longpeng Town （LP） and Shaochong Town （SC） in Shiping County in Honghe Hani and Yi Autonomous Prefecture. [Result] According to weights, the factors from high to low were as follows： soil〉light〉elevation〉slope〉 water conservancy〉transport〉baking facility〉planting plans over the years〉others. The similarity of geographical conditions in the area was 0.894 3, which indicated that the planting conditions in the two regions are similar. If farmer population in unit area, farmland quantity for individual farmer, labors in every household, activity in planting flue-cured tobacco and work of local instructor were considered, the weights of different factors were as follows： farmer population in unit area〉farmland quantity for individual farmer〉farmers＇ activity in planting flue-cured tobacco〉educational back- ground〉labor force in every household〉instructor〉population of farmers＇ children at- tending school. The similarity of geographical conditions was 0.703 1, which indicated that it is none-natural factors that influence yield and quality of flue-cured tobacco. [Conclusion] According to analysis on suitable planting area of flue-cured tobacco based on assessment of spatial scene similarity, similarity of growing conditions in two spatial scenes can be analyzed and evaluated, which would promote further exploration on, influencing factors and effects on tobacco production.

Regulation of 2-acetyl-1-pyrroline and grain quality in early-season indica fragrant rice by nitrogen and silicon fertilization under different plantation methods

Fragrant rice has a high market value,and it is a popular rice type among consumers owing to its pleasant flavor.Plantation methods,nitrogen(N)fertilizers,and silicon(Si)fertilizers can affect the grain yield and fragrance of fragrant rice.However,the core commercial rice production attributes,namely the head rice yield(HRY)and 2-acetyl-1-pyrroline(2-AP)content of fragrant rice,under various nitrogen and silicon(N-Si)fertilization levels and different plantation methods remain unknown.The field experiment in this study was performed in the early seasons of 2018 and 2019 with two popular indica fragrant rice cultivars(Yuxiangyouzhan and Xiangyaxiangzhan).They were grown under six N-Si fertilization treatments(combinations of two levels of Si fertilizer,0 kg Si ha^(−1)(Si0)and 150 kg Si ha^(−1)(Si1),and three levels of N fertilizer,0 kg N ha^(−1)(N0),150 kg N ha^(−1)(N1),and 220 kg N ha^(−1)(N2))and three plantation methods(artificial transplanting(AT),mechanical transplanting(MT),and mechanical direct-seeding(MD)).The results showed that the N-Si fertilization treatments and all the plantation methods significantly affected the HRY and 2-AP content and related parameters of the two different fragrant rice cultivars.Compared with the Si0N0 treatment,the N-Si fertilization treatments resulted in higher HRY and 2-AP contents.The rates of brown rice,milled rice,head rice,and chalky rice of the fragrant rice also improved with the N-Si fertilization treatments.The N-Si fertilization treatments increased the activities of N metabolism enzymes and the accumulation of N and Si in various parts of the fragrant rice,and affected their antioxidant response parameters.The key parameters for the HRY and 2-AP content were assessed by redundancy analysis.Furthermore,the structural equation model revealed that the Si and N accumulation levels indirectly affected the HRY by affecting the N metabolism enzyme activity,N use efficiency,and grain quality of fragrant rice.Moreover,high N and Si accumulation directly promoted the 2-AP content or affected the antioxidant response parameters and indirectly regulated 2-AP synthesis.The interactions of the MT method with the N-Si fertilization treatments varied in the fragrant rice cultivars in terms of the HRY and 2-AP content,whereas the MD method was beneficial to the 2-AP content in both fragrant rice cultivars under the N-Si fertilization treatments.

Effects of planting patterns on yield, quality, and defoliation in machine-harvested cotton

The aim of this study was to elucidate the effects of different machine-harvested cotton-planting patterns on defoliation,yield,and fiber quality in cotton and to provide support for improving the quality of machine-harvested cotton.In the 2015 and 2016 growing seasons,the Xinluzao 45(XLZ45)and Xinluzao 62(XLZ62)cultivars,which are primarily cultivated in northern Xinjiang,were used as study materials.Conventional wide-narrow row(WNR),wide and ultra-narrow row(UNR),wide-row spacing with high density(HWR),and wide-row spacing with low density(LWR)planting patterns were used to assess the effects of planting patterns on defoliation,yield,and fiber quality.Compared with WNR,the seed cotton yields were significantly decreased by 2.06–5.48%for UNR and by 2.50–6.99%for LWR,respectively.The main cause of reduced yield was a reduction in bolls per unit area.The variation in HWR yield was–1.07–1.07%with reduced bolls per unit area and increased boll weight,thus demonstrating stable production.In terms of fiber quality indicators,the planting patterns only showed significant effects on the micronaire value,with wide-row spacing patterns showing an increase in the micronaire values.The defoliation and boll-opening results showed that the number of leaves and dried leaves in HWR was the lowest among the four planting patterns.Prior to the application of defoliating agent and before machine-harvesting,the numbers of leaves per individual plant in HWR were decreased by 14.45 and 25.00%on average,respectively,compared with WNR,while the number of leaves per unit area was decreased by 27.44 and 36.21%on average,respectively.The rates of boll-opening and defoliation in HWR were the highest.Specifically,the boll-opening rate before defoliation and machine-harvesting in HWR was 44.54 and 5.94%higher on average than in WNR,while the defoliation rate prior to machine-harvesting was 3.45%higher on average than in WNR.The numbers of ineffective defoliated leaves and leaf trash in HWR were the lowest,decreased by 33.40 and 32.43%,respectively,compared with WNR.In conclusion,the HWR planting pattern is associated with a high and stable yield,does not affect fiber quality,promotes early maturation,and can effectively decrease the amount of leaf trash in machine-picked seed cotton,and thus its use is able to improve the quality of machine-harvested cotton.

法舒地尔缓解β-淀粉样蛋白1-42诱导的SH-SY5Y细胞凋亡

背景:法舒地尔对阿尔茨海默病小鼠脑内的线粒体动力学有调节作用,并且可以抑制神经炎症,但能否调节线粒体自噬和NLRP3炎症小体进而减轻β-淀粉样蛋白毒性尚不清楚。目的:探究法舒地尔对β-淀粉样蛋白1-42诱导的人源神经母细胞瘤细胞株SH-SY5Y凋亡和线粒体自噬以及NLRP3炎症小体的调节作用。方法:将SH-SY5Y细胞接种于孔板内,细胞贴壁后分3组干预:对照组不加入任何药物,模型组加入20μmol/L β-淀粉样蛋白1-42,法舒地尔组同时加入20μmol/L β-淀粉样蛋白1-42与15 mg/L法舒地尔,干预24 h后,采用MTT法检测细胞活性,TUNEL染色检测细胞凋亡,qRT-PCR和Western blot检测凋亡相关蛋白表达,免疫荧光染色和Western blot检测线粒体自噬相关蛋白表达,免疫荧光染色和Western blot检测NLRP3炎症小体相关蛋白表达。结果与结论:(1)与对照组比较,模型组细胞活性降低、凋亡率升高(P<0.05);与模型组比较,法舒地尔组细胞活性升高、凋亡率降低(P<0.05);(2)qRT-PCR和Western blot检测结果显示,与对照组比较,模型组细胞Bax mRNA与蛋白表达升高(P<0.05),Bcl-2 mRNA与蛋白表达降低(P<0.05);与模型组比较,法舒地尔组细胞Bax mRNA与蛋白表达降低(P<0.05),Bcl-2 mRNA与蛋白表达升高(P<0.05);(3)免疫荧光染色和Western blot检测结果显示,与对照组相比,模型组细胞PINK1、帕金森病蛋白和LC3蛋白表达降低(P<0.05),p62蛋白表达升高(P<0.05);与模型组相比,法舒地尔组细胞PINK1、帕金森病蛋白和LC3蛋白表达升高(P<0.05),p62蛋白表达降低(P<0.05);(4)免疫荧光染色和Western blot检测结果显示,与对照组相比,模型组细胞NLRP3、ASC、Caspase-1和白细胞介素1β蛋白表达升高(P<0.05);与模型组相比,法舒地尔组细胞NLRP3、ASC、Caspase-1和白细胞介素1β蛋白表达降低(P<0.05);(5)结果表明,法舒地尔可以减轻β-淀粉样蛋白1-42诱导的SH-SY5Y细胞凋亡,其机制可能与激活线粒体自噬且抑制NLRP3炎症小体激活有关。

Sex-specific facilitation and reproduction of the gynodioecious cushion plant Arenaria polytrichoides on the Himalaya-Hengduan mountains,SW China

When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytrichiodes as a model species,we aimed to assess the sex-specific facilitation intensity of cushion plant by measuring the beneficiary cover ratio,and to assess the potential costs in cushion reproductive functions by measuring the flower and fruit cover ratios.The total beneficiary cover ratio was similar between females and hermaphrodites.Females produced much less flowers but more fruits than hermaphrodites.These results suggested that females and hermaphrodites possess similar facilitation intensity,and female cushion A.polytrichoides may allocate more resources saved from pollen production to seed production,while hermaphrodites possibly allocate more resources to pollen production hence reducing seed production.The surface areas covered by beneficiaries produced less flowers and fruits than areas without beneficiaries.In addition,strong negative correlations between beneficiary cover and flower cover were detected for both females and hermaphrodites,but the correlation strength were similar for these two sex morphs.However,the correlation between beneficiary cover and fruit cover was only significantly negative for females,suggesting that beneficiary plants negatively affect fruit reproduction of females while have neutral effects on hermaphrodites.All the results suggest that to facilitate other beneficiaries can induce reproductive costs on cushion A.polytrichoides,with females possibly suffering greater cost than hermaphrodites.Such differentiation in reproductive costs between sex morphs,in long-term perspective,may imply sex imbalance in population dynamics.

Increased dependence on nitrogen-fixation of a native legume in competition with an invasive plant

Suppression of roots and/or their symbiotic microorganisms,such as mycorrhizal fungi and rhizobia,is an effective way for alien plants to outcompete native plants.However,little is known about how invasive and native plants interact with the quantity and activity of nutrient-acquisition agents.Here a pot experiment was conducted with monoculture and mixed plantings of an invasive plant,Xanthium strumarium,and a common native legume,Glycine max.We measured traits related to root and nodule quantity and activity and mycorrhizal colonization.Compared to the monoculture,fine root quantity(biomass,surface area)and activity(root nitrogen(N)concentration,acid phosphatase activity)of G.max decreased in mixed plantings;nodule quantity(biomass)decreased by 45%,while nodule activity in Nfixing via rhizobium increased by 106%;mycorrhizal colonization was unaffected.Contribution of N fixation to leaf N content in G.max increased in the mixed plantings,and this increase was attributed to a decrease in the rhizosphere soil N of G.max in the mixed plantings.Increased root quantity and activity,along with a higher mycorrhizal association was observed in X.strumarium in the mixed compared to monoculture.Together,the invasive plant did not directly scavenge N from nodule-fixed N,but rather depleted the rhizosphere soil N of the legume,thereby stimulating the activity of N-fixation and increasing the dependence of the native legume on this N source.The quantity-activity framework holds promise for future studies on how native legumes respond to alien plant invasions.

Spatio-Temporal Changes in the Rice Planting Area and Their Relationship to Climate Change in Northeast China: A Model-Based Analysis

Rice is one of the most important grain crops in Northeast China （NEC） and its cultivation is sensitive to climate change. This study aimed to explore the spatio-temporal changes in the NEC rice planting area over the period of 1980-2010 and to analyze their relationship to climate change. To do so, the CLUE-S （conversion of land use and its effects at small region extent） model was ifrst updated and used to simulate dynamic changes in the rice planting area in NEC to understand spatio-temporal change trends during three periods： 1980-1990, 1990-2000 and 2000-2010. The changing results in individual periods were then linked to climatic variables to investigate the climatic drivers of these changes. Results showed that the NEC rice planting area expanded quickly and increased by nearly 4.5 times during 1980-2010. The concentration of newly planted rice areas in NEC constantly moved northward and the changes were strongly dependent on latitude. This conifrmed that climate change, increases in temperature in particular, greatly inlfuenced the shift in the rice planting area. The shift in the north limit of the NEC rice planting area generally followed a 1＆#176;C isoline migration pattern, but with an obvious time-lag effect. These ifndings can help policy makers and crop producers take proper adaptation measures even when exposed to the global warming situation in NEC.

Comparison of yield traits in rice among three mechanized planting methods in a rice-wheat rotation system

Understanding the differences in yield traits of rice among pothole seedling of mechanical transplanting （PSMT）, carpet seedling of mechanical transplanting （CSMT） and mechanical direct seeding （MDS） is of great importance not only for rice scientists but also for rice farmers to develop a high-yield production system under mechanical conditions in a rice-wheat rotation system. However, such traits are yet to be studied among rice varieties ofjaponica-indica hybrid rice （JIHR）,japonica conventional rice （JCR） and indica hybrid rice （IHR）. Field experiments were conducted in 2014 and 2015, where six cultivars of the three rice types JIHR, JCR and IHR were grown individually with PSMT, CSMT and MDS methods, under respective managements for each method to achieve the maximum attainable yield. Results showed that （i） the PSMT significantly increased grain yield of JIHR by 22.0 and 7.1%, of JCR by 15.6 and 3.7% and of I HR by 22.5 and 7.4%, compared to MDS and CSMT on average across the two years, respectively. The highest yield was produced by the combination of JIHR and PSMT; （ii） high yield under PSMT was mainly attributed to large sink capacity and high-efficient dry matter accumulation. With sufficient panicles per hectare, the increase of spikelet number per panicle, especially the increase in spikelet number of the secondary rachis-branches was determined to be the optimal approach for developing a large sink capacity for rice under PSMT. The optimal tillers development, large leaf area index at heading stage, and high leaf area duration, crop growth rate and net assimilation rate during grain-filling phase could be the cause of sufficient dry matter accumulation for rice under PSMT; （iii） moreover, the PSMT favored plant growth as well as enriched the stems plus sheaths during grain-filling phase, as compared with CSMT and MDS. These results suggest that PSMT may be an alternative approach to increasing grain yield in a rice-wheat rotation system in the lower reaches of the Yangtze River in China.

Effect of Long-Term Application of K Fertilizer and Wheat Straw to Soil on Crop Yield and Soil K Under Different Planting Systems

Effect of application of K fertilizer and wheat straw to soil on crop yield and status of soil K in the plough layer under different planting systems was studied. The experiments on long-term application of K fertilizer and wheat straw to soil in Hebei fluvo aquic soil and Shanxi brown soil in northern China were begun in 1992. The results showed that K fertilizer and straw could improve the yields of wheat and maize with the order of NPK ＋ St 〉 NPK 〉 NP ＋ St 〉 NP, and treatment of K fertilizer made a significant difference to NP, and the efficiency of K fertilizer in maize was higher than in wheat under rotation system of Hebei. In contrast with Shanxi, the wastage of soil potassium was a more serious issue in the rotation system in Hebei, only treatment of NPK ＋ St showed a surplus of potassium and the others showed a wane. K fertilizer and straw could improve the content of water-soluble K, nonspecifically adsorbed K, non-exchangeable K, mineral K, and total K in contrast to NP; however, K fertilizer and straw reduce the proportion of mineral K and improve proportion of other forms of potassium in the two locating sites. Compared with the beginning of orientation, temporal variability character of soil K content and proportion showed a difference between the two soil types; furthermore, there was a decrease in the content of mineral K and total K simultaneously in the two locating sites. As a whole, the effect of K fertilizer applied to soil directly excelled to wheat straw to soil. Wheat straw to soil was an effective measure to complement potassium to increase crop yield and retard the decrease of soil K.

自旋-轨道耦合作用下极化激元凝聚中的调制不稳定性

利用线性稳定性分析方法,对存在自旋-轨道耦合(SOS)作用的二维极化激元玻色-爱因斯坦凝聚(BEC)系统中的调制不稳定性(MI)进行了研究.分析了组分内部,组分之间以及SOC相互作用对系统调制不稳定性的影响.结果显示,当系统内部不存在SOC作用,组分之间的相互作用为0,组分内部存在排斥作用时,不会出现调制不稳定性,组分内部存在吸引作用时,会出现调制不稳定性,并且调制不稳定性区间长度随吸引作用的增强而增加;组分之间相互作用不为0时,组分之间的相互作用以平方形式出现,其正负不会对调制不稳定性产生实质性影响.存在SOC相互作用时,SOC相互作用会引起增益谱曲线的不规则振荡,破坏原来的调制不稳定性区间.

Multi-Location Investigation of Optimum Planting Density and Boll Distribution of High-Yielding Cotton (G.hirsutum L.) in Hubei Province,China

Cotton yield per unit ground area has stagnated for a dozen years in Hubei Province, China, although a series of new high- yielding varieties have been commercialized. A multi-location investigation was carried out in 2008 and 2009 in 13 counties to determine if increased planting population density （PPD） would break the stagnant yield. The results showed that significant differences among the fields existed in theoretical yield, PPD, and bolls per square meter （BPM）. The lowest yield of 1 641.1 kg ha-I was resulted from the lowest PPD of 1.7 plants m-2 and the lowest BPM of 71.8 bolls m-2, while the highest yield of 2 779.7 kg ha-~ was resulted from the highest PPD of 2.5 plants m-2, and the highest BPM of 129.4 bolls m-z. Plant mapping revealed that boll retention rate （BRR） was maintained over 30 or 40% for the first 17-18 fruiting branches （FBs） and decreased dramatically thereafter, rotten boll rate （RBR） decreased, but open boll rate （OBR） rose first and dropped later with rising FB from the bottom to the top. But BRR, RBR, and OBR were all dropped with the fruiting positions （FPs） extending outwards. The optimum range of plant density would be 2-3 plants m-2 and the proper individual plant structure would be 16-19 FBs with 5-7 FPs for cotton production in Hubei Province.

Microstructure of a Planting Material Consisting of Nutrition-Expansive Perlitic-Cement Composites

An ecotypic revetment material consisting of nutrition-expansive perlitic-cement composites is introduced. This planting material can combine vegetation recovery with slope protection. The XRD, SEM and image analysis techniques were used to study its composition and microstructure. Its strength was measured by an electro-hydraulic servo-controlled testing machine. The results show the unconfined compressive strength is about 393.6 kPa, and the average elastic modulus is about 47.0 MPa. The quartz, felspar, chlorite and calcite are the main non-clay minerals in the planting material. Its particles are mainly spherical,and the range of the equivalent diameter is 1.83 to 15.96 μm. The results also show the planting material contains a large amount of micro non-capillary and capillary pores, and has a microstructure characteristic of honeycomb and coralline. CSH gel produced by hydration of cement increases the strength and water stability of the particles. The anisotropy and slight orientation of the particles increase the void cross-section area,providing an explanation of the high permeability for the planting material.The better porosity of the planting material is apt tokeep moisture and nutriment, provides oxygen for plant root breathing, and aids to exhaust the carbon dioxide by means of exchanging with atmosphere, hence it can facilitate vegetation.

双偶氮苯-二苯并[b,i]噻蒽-[2,3-b]苯-5,7,12,14-四酮衍生物分子的二阶非线性光学性质

使用密度泛函理论(DFT)M06-2X方法、采用6-311+g(d,p)基组,分别对26个双偶氮-二苯并[b,i]噻蒽-[2,3-b]苯-5,7,12,14-四酮衍生物分子进行结构优化与频率计算;使用含时密度泛函理论(TD-DFT)TD-M06-2X方法计算了a1~d6分子的前线分子轨道与电子吸收光谱,采用有效场FF方法研究了二阶非线性光学性质(NLO).研究结果表明,26个噻蒽四酮类衍生物分子的能隙在1.33—2.02 eV范围,归属于有机半导体;最低能量吸收峰波长在601.8~609.5nm范围;在增大分子的二阶非线性光学系数β_(μ)(或β_(0))值方面,含相同偶氮苯基团或含不同偶氮苯基团分别引入到二苯并[b,i]噻蒽-[2,3-b]苯-5,7,12,14-四酮分子两侧的2,10位优于2,9位,在2,10位分别端接含推、拉基团的偶氮苯优于含相同给电子基团的偶氮苯.在偶氮苯苯环对位分别端接强吸电子基(-NO_(2))与强供电子基(如-N(CH_(3))_(2)、-N(Ph)_(3)、-N-苯基咔唑等)可增强体系的二阶非线性光学性能,获得性能良好的非线性光学材料.

Effect of Planting Density,Fertilizer Level,and Number of Seedlings per Hole on Yield of Coix Lachryrma-jobi L.

In order to study high yield cultivation technology for Coix Lachryrma-jobi L.,and discuss the effect of planting density,fertilizer level,and number of seedlings per hole on yield of Coix Lachryrma-jobi L.,this paper took domesticated variety Xingren Small White Shell of Coix Lachryrma-jobi L. as an example. Using L9( 34) orthogonal design,it selected optimum combination of planting density,fertilizer level,and number of seedlings per hole to guide planting of Coix Lachryrma-jobi L.. Experiment indicated that the optimum planting density( spacing in the rows and spacing between rows) of Coix Lachryrma-jobi L. is 40 cm x 80 cm; the optimum fertilizer level is pure nitrogen 15 kg,pure phosphorus 15 kg and pure potassium 15 kg per mu; the optimum number of seedlings per hole is 5 seedlings per hole. Through variance analysis,it indicated that planting density exerts significance effect on the yield of Coix Lachryrma-jobi L.

Enrichment planting in a logged-over tropical mixed deciduous forest of Laos

Enrichment planting is commonly used for increasing the density of desired tree species in secondary forests often characterized by a prevalence of low commercial species. The objectives of the study were to identify the optimal enrichment planting method vis-à-vis gap and line planting, and to evaluate the performance of two dipterocarps （Vatica cinerea and Dipterocarpus alatus） and three legumes （Afzelia xylocarpa, Pterocarpus macrocarpus, Dalbergia cochinchinensis） planted in logged-over mixed deciduous forest of Laos. The enrichment planting trial was arranged in a randomized complete block design with seven replica-tions. Survival, height and diameter were measured seven years after planting and subjected to analysis of variance. Survival rate of planted seedlings did not vary between enrichment planting （p 0.05）. However, diameter and height growth was favored more in gaps than in planting lines. This was related to rapid canopy closure in both gaps and lines, albeit more remarkable in planting lines. Significant inter-species varia-tion was detected for survival rate, height and diameter. The shade-tolerant dipterocarps had better survival and growth than the light-demanding leguminous species （p 0.0001）. The size class distribution of individuals was irregular, accentuating uneven light condition in the understory. Given the difficulty to maintain constant line width and even light condi-tion, the cost of annual clean operation and the rigid geometric patterns of planting lines, the use of logged-over gaps for enrichment planting is recommended. Dipterocarpus alatus and V. cinerea are recommended for enrichment planting in mixed deciduous forests. A. xylocarpa, D. cochi-chinensis and P. macrocarpus can be planted in wider gaps, lines and open sites as plantation of mixed species or under canopy of young swidden forests.