水培法磷矿石对小麦生长的影响

Screening cultivars to grow under conditions of low phosphorus (P) availability and utilize P efficiently from compounds of low solubility in soils may be beneficial to overcome poor plant growth in P-deficient soils.The growth behavior and P utilization efficiency of seven wheat cultivars grown in hydroponics were studied,using rock phosphate as P source.The wheat cultivars grown for 30 days were significantly different in biomass accumulation,P uptake and P utilization efficiency.The dry matter production of all the cultivars was significantly correlated with P uptake,which in turn correlated to the drop in the root medium pH.The ranking of wheat cultivars on the basis of dry matter yield,P uptake and P utilization efficiency was Zamindar 80 ＞ Yccora ＞ C 271 ＞ WL 711 ＞ Barani 83 ＞ PARI 73 ＞ Rohtas.The cultivar Zamindar 80 appeared to possess the best growth potential in P-deficient soils.     

Atmospheric sulfur deposition for a red soil broadleaf forest in southern China

A two-year study in a typical red soil region of Southern China was conducted to determine 1) the dry deposition velocity (Vd) for SO2 and particulate SO4^2- above a broadleaf forest, and 2) atmospheric sulfur fluxes so as to estimate the contribution of various fractions in the total. Using a resistance model based on continuous hourly meteorological data, atmospheric dry sulfur deposition in a forest was estimated according to Va and concentrations of both atmospheric SO2 and particulate SO2^4-. Meanwhile, wet S deposition was estimated based on rainfall and sulfate concentrations in the rainwater. Results showed that about 99% of the dry sulfur deposition flux in the forest resulted from SO2 dry deposition.In addition, the observed dry S deposition was greater in 2002 than in 2000 because of a higher average concentration of SO2 in 2002 than in 2000 and not because of the average dry deposition velocity which was lower for SO2 in 2002. Also,dry SO2 deposition was the dominant fraction of deposited atmospheric sulfur in forests, contributing over 69% of the total annual sulfur deposition. Thus, dry SO2 deposition should be considered when estimating sulfur balance in forest ecological systems.     

稻田土壤甲烷排放模型: Ⅱ. 模型的验证和应用

Fifteen upland soils collected from the major arable areas in NOrth China were used to assess the availability of soil sulfur(S) to plants in a pot experiment.Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES),respectively.In addition,mineralizable organic S,organic S,N/S ratio,sulfur availability index(SAI) and available sulfur correction value(ASC) in soils were also determined.The S amout extracted by 1.5g L^-1 CaCl2 was nearly equivalent to that by 0.25mol L^-1 KCl(40℃),and both of them were slightly smaller than that by 0.01 molL^-1 Ca(H2PO4)2 solution,as measured by turbidimetric method or ICP-AES.The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES.All methods tested except that for organic S and N/S ratio produced satisfactoy results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment,In general,0.01 mol L^-1 Ca(H2PO4)2-extracted S determined by ICP-AES or turbidimetric method and 0.25mol L^-1 KCl(40℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S.     

中国华东地区农田大气硫沉降

Atmospheric sulfur deposition onto typical farmland in East China was investigated using both field measurements and numerical modeling. The field measurements were conducted at the Experiment Station of Red Soil Ecology, Chinese Academy of Sciences, 10 km from Yingtan, Jiangxi Province, East China, between November 1998 and October 1999, and at the Changshu Ecological Experiment Station, Chinese Academy of Sciences, in a rapidly developing region of Jiangsu Province, East China, between April 2001 and March 2002. The regional acid deposition model system (RegADMS), in which the dry deposition velocities of SO2 and sulfate aerosols (SO4^2-) were estimated using a big-leaf resistance analogy model, was applied to simulate air sulfur deposition over East China and sulfur deposition onto lands of different use types in East China. The wet scavenging coefficients were parameterized in terms of precipitation rate, and the effect of sub-grid processes due to inhomogeneous land use on dry deposition velocity was also included. Results of the field measurements showed that over 83% of the total sulfur deposition at the Yingtan site was dry deposition, while at the Changshu site 42% was dry deposition. The total sulfur deposition was much larger at the Yingtan site than at the Changshu site, which suggested contrasting air pollution and meteorological situations. The modeling results revealed that the total annual sulfur deposition over East China was 1.88 Mt, of which 72.8% was deposited onto farmland, and dry deposition accounted for 43% of the total sulfur deposited. The modeling results were generally in agreement with those from the observations.Overall, this study suggested that atmospheric sulfur deposition played an important role in the soil sulfur balance, which could have a significant effect on agricultural ecosystems in the study region.     

中国青海湖地区草地蝗虫与土壤的关系

A growth chamber study was conducted to determine the relationships between the supply of soil available nitrogen （N） and sulfur （S） and canola （Brassica napus） and wheat （Triticum aestivum L. ‘Biggar＇） N and S uptake and yield in three Western Canadian soils. The suitability of one-hour burial with an anion exchange membrane （AEM） was assessed for its utility as a quick test of the available N：S balance in the soil. Canola and wheat were grown on a Luvisolic soil low in available S and on Brown and Black Chernozemic soils low in both available N and S, with different rates and combinations of N and S fertilizers applied. AEM burial was used to assess soil available nitrate and sulfate supply rates after fertilization. Dry matter yield and N and S concentrations in plant tissues were determined after 6 weeks of growth. The soil available N：S ratio determined by AEM burial closely reflected the relative supplies of available N and S as revealed in the N：S ratios of plant tissue dry matter. The highest yields were achieved where the available N：S ratio in soil and plant tissue ranged from 5 to 13. Thus, a one-hour burial of an AEM probe in the field may be a useful tool to quickly test if a balanced N and S supply is present in the soil for optimum crop yield.     

小麦和燕麦两种作物镁吸收和坡缕石转化能力研究

Weathering of clay minerals is a source of nutrients to plants. Palygorskite is a Mg-rich fibrous clay mineral that commonly occurs in the soils and sediments of arid regions. Although many studies have examined the environmental conditions required for the formation and stability of palygorskite, information on the transformation of this mineral in the root zone (or rhizosphere) of agricultural crops is limited. This study explored the possibility of palygorskite transformation in the rhizosphere of wheat and oat and compared the ability of these crops to extract structural Mg from palygorskite. The crops were cultivated in pots consisting of a mixture of sand from Hamadan region, Iran and Florida palygorskite, irrigated with distilled water, and treated with either complete or Mg-free nutrient solutions. After 100 d, Mg uptake by the crops was measured. Clay-sized particles in each pot were also separated from the sand and were analyzed through X-ray diffraction (XRD). The X-ray pattern of the particles was compared with that of the pure palygorskite particles (before cultivation). The results showed that palygorskite could provide sufficient Mg for the growth of wheat in the pots supplied with Mg-free nutrient solution. In spite of the magnesium uptake by both plants from the palygorskite structure, no detectable peaks indicating the transformation of palygorskite were recognized by XRD. A decrease of 1.05 nm in peak intensity was more obvious for the pots containing palygorskite and irrigated with Mg-free nutrient solution than for the pots irrigated with complete nutrient solution. Although the decrease in peak intensity was greater for oat than wheat, indicating greater palygorskite weathering by oat, Mg uptake by oat was low, as evidenced by the deficiency symptoms observed.     

混合施用微咸水和氮肥对甜高粱生物量和产糖量的影响

Soil salinization and non-point source pollution are among the most important and widespread environmental problems in European Mediterranean regions. Sweet sorghum (Sorghum bicolor (L.) Moench var. saccharatum) is a moderate to high salinity tolerant crop with low water and nutrient needs, seen as an alternative to grow in the water scarce regions. A three-year multifactorial study was conducted in southern Portugal to evaluate the combined effects of saline water and nitrogen application on the dry biomass (total, stems, and leaves), sugar content (total reducing sugars and sucrose contents), and sugar yield (here defined as the product of total reducing sugars and stems dry biomass) functions of sweet sorghum. Sorghum dry biomass and sugar yield showed diminishing returns for each incremental change of nitrogen. The use of saline irrigation waters also led to yield reduction. Exception was sucrose content which increased with increasing levels of sodium in the soil. Nitrogen need decreased as the amount of sodium applied increased. Stem dry biomass, sucrose content, and sugar yield progressively increased with progress in the experiment. The effect could be attributed to the increase of the amount of irrigation applied throughout the years, thus increasing the leaching fraction which promoted salt leaching from the root zone, reduced the salinity stress, increased plant transpiration, nitrogen uptake and biomass yield.     

在施钾条件下灌溉水稻的养分吸收和利用效率研究

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

Nutrient Uptake and Use Efficiency of Irrigated Rice in Response to Potassium Application

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N,P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

三叶草对污染土壤中芘的去除研究

Phytoremediation has been used as an emerging technology for remediation of soil contamination with polycyclic aromatic hydrocarbons (PAHs), ubiquitous persistent environmental pollutants derived from natural and anthropogenic processes, in the last decade. In this study, a pot experiment was conducted to investigate the potential of phytoremediation of pyrene from spiked soils planted with white clover (Trifolium repens) in the greenhouse with a series of pyrene concentrations ranging from 4.22 to 365.38 mg kg^-1. The results showed that growth of white clover on pyrenecontaminated soils was not affected. The removal of pyrene from the spiked soils planted with white clover was obviously higher than that from the unplanted soils. At the end of the experiment (60 d), the average removal ratio of pyrene in the spiked soils with white clover was 77%, which was 31% and 57% higher than those of the controls with or without micobes, respectively. Both roots and shoots of white clover took up pyrene from the spiked soils and pyrene uptake increased with the soil pyrene concentration. However, the plant-enhanced dissipation of soil pyrene may be the result of plant-promoted microbial degradation and direct uptake and accumulation of pyrene by white clover were only a small part of the pyrene dissipation. Bioconcentration factors of pyrene (BCFs, ratio of pyrene, on a dry weight basis, in the plant to that in the soil) tended to decrease with increase in the residual soil pyrene concentration. Therefore, removal of pyrene in the contaminated soils was feasible using white clove.     

Status of Sulfur in Mulberry Leaves–Silkworm Cocoon System of Typical Mulberry Gardens in the Lower to Middle Reaches of the Yangtse River

Concentration of sulfur (S) in mulberry leaves was 1.44 ～ 2.67 g kg^?1 (Mean ± SE = 2.03 ± 0.30 g kg^?1) in the six provinces of Jiangxi, Anhui, Hubai, Hunan, Jiangsu, and Fujian, China. Concentration of S in mulberry leaves was influenced significantly by the concentration of available S in soils of mulberry gardens (R ² = 0.1773**, n = 52). Sulfur concentration in mulberry leaves, cocoon shells, silkworm pupae, and silkworm excrement in high-yielding mulberry gardens was higher than that in low-yielding mulberry gardens. The curvilinear correlation between concentration of sulfur in mulberry leaves and cocoon shells was significant (R ² = 0.2101*, n = 26, a < 0).     

桑园土壤—桑叶—蚕茧系统硫素相关规律研究

采用典型地区桑园面上调查取样和实验室分析相结合的研究方法对长江中下游地区典型桑园的硫素状况进行研究。结果表明 :表土 ( 0～ 2 0cm)有效硫含量为 2 5 1～87 73mgkg- 1(均值 1 8 34± 1 5 2 5mgkg- 1) ,底土有效硫含量比表土有所增加 ,二者极显著正相关。缺硫土样占 5 5 77% ,以皖、赣、鄂、闽等省红砂岩、花岗岩母质形成的土壤为典型缺硫土壤 ,其次为赣、湘、苏的河流冲积物母质土壤。桑园土壤有效硫含量与桑叶全硫含量呈极显著二次曲线相关 (R2 =0 1 773 ,n =5 2 ,a <0 ) ;桑叶全硫含量与茧层全硫含量呈显著二次曲线相关 (R2 =0 2 1 0 1 ,n =2 6,a <0 )、与蛹全硫含量呈极显著直线正相关 (R2 =0 2 5 1 5 ,n =2 7)。高产桑园土壤有效硫含量及桑叶、茧层、蛹、蚕沙全硫含量均比低产桑园高     

氮钾肥配合施用对桑叶产量品质及蚕茧质量的影响

通过连续4年田间施肥试验和一季养蚕试验,研究了氮肥和钾肥配合施用对桑叶产量、品质及相应桑叶喂饲家蚕对蚕生长及蚕茧品质的影响。结果表明,桑园施用氮钾肥显著提高桑叶产量,在氮钾肥各养分配比中,以高氮高钾处理(N450K300)的产量最高,比N0K0处理年均增产35.2%,与其他各处理产量差异显著。桑叶品质分析结果表明,桑叶中必需氨基酸、氨基酸总量、粗蛋白、油脂含量随氮肥用量增加而提高,但单施氮肥会对蛋氨酸和油脂含量产生负面影响;施钾导致糖分含量下降,其他品质参数值随钾肥施用而提高,氮钾肥配合施用具有提高桑叶品质的作用。养蚕结果表明,桑园增施氮钾肥生产出的桑叶,有助于降低蚕茧的死笼率、具有提高全茧量和茧层率及提高蚕茧产量的作用。蚕茧上茧率、茧丝长、解舒率和茧丝净度随着钾肥用量的增加而提高,在施钾基础上增加氮肥用量有提高蚕茧品质的作用,但不施钾只施氮肥对上茧率有负面影响,说明氮钾肥配合施用能促进蚕茧质量的提高。     

Mulberry nutrient management for silk production in Hubei Province of China

The silk industry is important for south China's rural economy. Leaves of mulberry (Morus spp.) are used for silkworm production. Hubei province is one of the main silk‐producing provinces in China. The objectives of this research were to survey the fertilization practices in the mulberry‐producing regions in the province and to determine the best nutrition‐management practice for mulberry plantations. A survey and a series of field experiments with N, P, K, and micronutrients were conducted from 2001 to 2002. In addition, a silkworm‐growth experiment was also conducted by feeding leaves harvested from various fertilization treatments. The results indicate that poor soil fertility and unbalanced fertilization were the main factors limiting mulberry‐leaf yield and quality in Hubei province. Nitrogen fertilization of mulberry has reached a high level (454 kg ha^–1 y^–1) in Hubei province, but P‐ and K‐fertilization rates have not been matched with N‐fertilization rates as farmers are not aware of the significance of P and K. Balanced fertilization showed positive nutrient interactions with respect to mulberry yield and quality. Potassium application increased yield and quality (protein and sugar concentration) of mulberry leaves. Silkworm growth and cocoon quality were improved when silkworms were fed with the leaves derived from K‐fertilized plants in comparison with those taken from control plots. Application of Mg, S, and B also significantly improved leaf sugar, essential and total amino acid concentrations, but did not increase leaf yield significantly. It is concluded that a fertilizer dose of 375 kg N ha^–1, 66 kg P ha^–1, and 125 kg K ha^–1 is suitable for the cultivation of mulberry in the Hubei province along with Mg, S, and B, wherever necessary, for the improvement of yield and quality of mulberry leaves.     

桑蚕尿素添食对产丝的效应及其机理

在五龄期每日1次叶面添食尿素氮,保留在熟蚕体内的尿素氮量为添加量的22—36%,蚕粪中回收为25—33%,剩桑中11%左右,25—30%没有回收到,可能以NO、NO_2等气态形式损失,未能查明。蚕体吸收的尿素氮有60%以上转移到丝腺中,占添加量的15—25%。茧层和丝中的尿素氮量不低于熟蚕丝腺中的量,说明转移到丝腺中的尿素氮已转化为丝素成分,但其贡献低于1%。即使增加添食次数、添食量或结合脲酶处理,也未使尿素氮对丝物质产量的贡献超过3%,所以尿素添食的直接作用不大。五龄期桑蚕对根外追肥标记桑叶的尿素氮的吸收、转移及熟蚕丝腺、茧层和丝中的尿素氮,比同样试验条件下叶面添食的低50%以上。五龄期1次添食的动态试验表明,在添食后一天内,尿素氮除以粪便排出外,还存在着其他损失途径。     

钾肥用量和品种对桑叶生产及蚕茧质量的影响

通过为期 4年的田间施肥试验和 1季养蚕试验 ,研究了钾肥用量和钾肥品种对桑叶产量、品质、养分吸收和蚕茧质量的影响。结果表明 ,施K2 O 1 5 0、30 0、375kghm-2 a-1 处理分别比不施K肥年均增产桑叶 2 3.9%、31 .7%、36 .0 %;等量钾肥时 ,KCl对桑叶增产效果基本等同于K2 SO4;施钾增产效果有逐年增加趋势 ,同时钾肥施用表现后效。施钾明显提高桑叶中N、K和S(K2 SO4为钾源时 )含量 ,而降低Ca、Mg和Zn含量 ,对P含量影响不大。结果显示 ,钾肥施用大幅度促进了桑树对各种养分的吸收 ,从而提高了肥料利用率。施钾明显促进桑叶品质的改善 ,随着钾肥用量增加 ,桑叶中必需氨基酸、氨基酸总量、蛋白质、糖分和油脂含量均呈增加趋势。KCl施用也能提高桑叶品质 ,但效果比K2 SO4差。蚕茧质量测试结果表明 ,桑树施钾后对喂养的蚕茧品质产生正面影响 ,蚕重、全茧量、上茧率、茧丝长、解舒率、茧丝净度等指标均因施钾而提高 ,高量钾比低量钾效果好 ,在等量钾用量时K2 SO4对蚕茧质量的促进作用明显好于KCl。     

锌对桑蚕生长影响的研究

以０．２％的硫酸锌喷洒桑叶用来饲蚕，可以提高蚕体血液中氨基酸总量，增加全茧量、茧层量和茧层率；提高成虫的授精率及产卵量。统计分析结果达极显著水平。     

家蚕种茧切削智能夹具设计与试验

为了提高家蚕种茧切削机械的自动化和智能化水平,适应不同品种的家蚕种茧制种切削需要,该文设计研究了一种家蚕种茧切削智能夹具。该夹具具有自动调整种茧位置状态并固定种茧的功能,能够迅速、准确地将以任意方式进入夹具内的不同形状和大小的种茧,自动调整为理想切削状态并固定,使高速转动的切削刀具沿夹具顶面水平切割种茧时不会伤到蚕蛹,且削口平整、便于实现蚕蛹与茧壳的自动分离。通过对10个不同种茧品种的切削试验表明:该智能夹具自动定位与固定功能的成功率达到98%以上,刀盘切削成功率大于97%,切削伤蛹率小于2%;不同形状和大小的单粒种茧以任意方式进入夹具内,到该智能夹具将其调整固定到位并切削完成所需时间为6~8 s,对各品种的家蚕种茧具有普遍适用性。     

INTERACTION EFFECT OF POTASSIUM AND SULFUR FERTILIZATION ON PRODUCTIVITY AND MINERAL NUTRITION OF SUNNHEMP

The interactive effect of potassium (K) and sulfur (S) fertilization on productivity and mineral nutrition of sunnhemp (Crotalaria juncea L.) was evaluated in a field experiment during 2008 and 2009 cropping seasons at Uttar Pradesh, India. Potassium and sulfur fertilizers increased fiber yield and nutrient uptake of sunnhemp. It was observed that an application of K and S at 40 kg ha^?1 each significantly increased the total dry matter, fiber yield, and nutrient uptake of sunnhemp. The crop yield response to the added S was greater than for K and the nutrient use efficiency was also higher at lower levels of fertilizer addition. The increased levels of K and S improved the number of nodules and crude protein content of sunnhemp leaves.     

X射线成像技术判别蚕茧性别

为了实现雌、雄蚕茧分开缫丝,该文提出了一种基于X射线成像技术的蚕茧性别判别方法。利用X射线成像装置获取蚕蛹图像,对蚕蛹图像预处理并提取7个形状特征后,分别采用线性判别分析(LDA)和BP人工神经网络(BPANN)建立判别模型。结果表明同一品种同一时期、同一品种不同时期、不同品种同一时期蚕茧的LDA判别模型性能优于BPANN判别模型;LDA模型识别正确率分别大于91.33%、86.73%、89.53%,BPANN模型识别正确率分别大于88.47%、81.97%、83.26%,且LDA模型判别时间(68.5 ms)远低于BPANN模型(503.6 ms)。研究结果可为蚕茧性别在线检测提供技术指导。