昆明西山山原红壤和红色石灰土的pH值与磁化率关系研究

通过对昆明西山山原红壤和红色石灰土的pH值和磁化率测试研究发现,山原红壤的pH值在4.0~5.8之间,呈酸性,质量磁化率在56×10-8~174×10-8m3/kg之间,pH值与磁化率呈明显的正相关关系;而红色石灰土pH值在6.0~8.4之间,磁化率为752×10-8~5 056×10-8m3/kg,pH值和磁化率呈负相关关系。该研究表明,在我国西南地区,土壤pH值和磁化率既存在明显的负相关关系也存在正相关关系。结合前人在其他地区的研究资料,进一步发现,土壤的酸碱环境可能是决定这些关系的重要因素。     

探析数字图书馆的建设

数字图书馆的建设是图书馆建设的发展方向,数字图书馆是未来图书馆的存在形式。介绍了数字图书馆的定义、建立数字图书馆的意义及数字图书馆的特点,指出了数字图书馆在建设中应解决的问题。     

干旱区绿洲土地利用变化的生态系统服务价值响应——以甘肃省金塔县为例

通过运用土地利用类型动态度、土地利用程度模型、生态系统服务价值估算模型和土地利用调查和变更数据等,分析1990年、2000年和2008年金塔县土地利用变化及其生态系统服务价值变化特征。结果表明:(1)1990—2008年间,耕地、园地、林地、建设用地和水域呈现增加趋势,牧草地和未利用地面积表现为减少趋势,总体土地利用程度为中下水平,处于发展阶段。(2)研究期间生态系统服务总价值呈现上升趋势,从1990年的47.238亿元增加到2008年的48.228亿元(+0.989 9亿元)。水域在研究区生态系统服务总价值中所占份额最大,草地生态服务功能的下降对生态系统服务总价值有明显的负贡献。(3)研究区各类生态系统的生物多样性保护、水源涵养和废物处理等服务性功能价值远大于其粮食生产和原材料等生产性功能价值。因此,该区域水土资源的合理利用与有效管理是实现生态系统服务功能维持和可持续发展的根本。     

神府矿区复垦土地土壤微量元素有效性影响因素研究

为了研究矿区不同复垦条件下,复垦土地土壤中有效微量元素与土壤环境的关系,采用实地试验与实验室分析相结合的方法,研究了不同复垦时间和复垦措施条件下土壤有效铜(Cu)、铁(Fe)、锰(Mn)、锌(Zn)4种微量元素有效态含量与土壤环境之间的关系。结果表明,研究区内土壤有效微量元素含量总体属于极低水平;土壤环境整体呈碱性,土壤pH值均在8.5以上,且变异系数属于小变异;土壤有机质无论是在不同恢复年限条件下,还是在不同治理措施条件下,其变异系数均属于高度变异。土壤环境与土壤有效微量元素相关关系分析结果表明,土壤pH值与土壤有效微量元素呈负相关关系,有效锰、有效铜与土壤pH值的相关性较高;土壤有机质与土壤有效微量元素呈正相关关系,其中有效锌、有效铜与土壤有机质含量的相关性较高。     

Effect of Harvest Timing on Yield and Mineral Nutritional Value of Kabuli Type Chickpea Seeds

Chickpea (Cicer arietinum L.) seeds are a good source of protein and mineral nutrients. However, there is no information regarding harvest timing on yield and mineral composition of chickpea seeds. The effect of harvest timing on seed yield, some yield components and mineral nutritional value of seeds of field grown chickpea plants in two different sites were studied. The mineral composition of chickpea straw depending on harvest timing was also evaluated in order to explain the variations of seed mineral concentrations in sink-source relationship manner. Yield and mineral nutritional value of chickpea were significantly affected by harvest timing. When compared to the seed yield at optimal harvest time, seed yield was 18% and 9% lower in the early harvest and 27% and 31% in the late harvest in Site 1 and Site 2, respectively. Late harvest of chickpea crops resulted in significant pod dropping and shattering. Generally, protein, phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and manganese (Mn) concentrations of the seeds in optimal harvest were found to be greater than in early and late harvested plants. Harvest timing also results in significant variations in straw mineral nutrient concentrations of the plants. As the results of this study, it was concluded that the harvest timing is critical for yield losses and mineral nutritional value of chickpea seeds.     

Use of Mefluidide to Alter Growth and Nutritive Value of Pearl Millet

Abstract

Pearl millet (Pennisetum americanum L. Leeke) has an inherent rapid growth rate that often presents management problems to achieve optimum utilization by livestock throughout the growing season. Both the rapid spring–summer growth rate and photoperiodism that diminishes growth in late summer—early fall creates the need to use both grazing and mechanical defoliation to have efficient use of forage production. The objectives of this 2‐year field study were to evaluate the effects of a growth regulator, mefluidide (N‐[2, 4‐dimethyl‐5‐([(trifluoromethyl) sulfonyl] amino) phenyl] acetamide), on growth characteristics and nutritive parameters of “Millex 24” pearl millet. Mefluidide was broadcast applied at different rates to determine the effect on dry matter (DM) yield and nutritive value of leaves and stems of pearl millet. Mefluidide reduced DM biomass at each weekly harvest, and at three weeks post‐treatment DM was reduced 3‐fold in Year 1 and 2‐fold in Year 2. Percent leaf, however, was nearly doubled by mefluidide application. Crude protein (CP) of leaves was not affected by mefluidide, however, CP of treated stems was significantly higher (P < 0.05) than untreated pearl millet. Fiber components were lowered (P < 0.05) in treated leaves and stems compared to untreated pearl millet. The 2‐year study showed that mefluidide enhanced nutritive value of pearl millet, but at the expense of DM.     

茶园套种牧草对作物产量及土壤基本肥力的影响

我国关于茶园生草和低层套(间)种研究起步很晚且报道甚少,有必要深入研究适宜我国茶园推广应用的低层茶草套(间)种模式。通过3年的田间小区试验,以不套种任何牧草处理为对照,研究了3种不同牧草[百喜草(Paspalum natatu)、白三叶(Trifolium repens)、平托花生(Arachis pintoi)]套种模式对茶青和鲜草产量及其茶园土壤基本肥力的影响。结果表明:3种不同牧草套种模式比对照提高茶青产量6.48%~20.26%,并收获鲜草产量1 352~4 023 kg·hm?2·a?1;3年来逐年减少茶园表土流失厚度幅度分别为25.0%~30.6%、33.3%~38.9%和53.3%~60.0%,并提高茶园土壤pH 9.64%~11.76%、有机质8.23%~76.13%、全氮13.59%~245.63%、全磷3.41%~210.51%、全钾1.37%~9.65%、碱解氮69.63%~109.33%和速效磷11.40%~34.20%;其中,茶园套种白三叶和套种平托花生处理对提高茶叶产量和茶园土壤基本肥力的效果相对更佳,值得在生产上进一步推广应用。     

西安市土地利用变化及其生态系统服务价值研究

基于西安市1989-2009年的土地利用基础数据,以1989年为基准年,研究西安市土地利用变化对生态系统服务价值的影响.结果表明:(1)研究区内1989-2009年土地利用变化较快,耕地、水域、草地、未利用地面积减少,建设用地、林地面积增加,土地利用综合指数下降了7.25;(2)研究区1989-2003年生态系统服务价值减少(2.60亿元),主要是因为建筑用地面积增加等造成的,2004年生态系统服务价值增加,2004-2009年生态系统服务价值在2004年的基础上减少了3.73亿元,此期间内耕地林地面积的减少、建设用地面积增加成为生态服务价值减少的主要影响因素.研究表明,西安市土地利用结构决定生态服务价值,生态服务价值反映了土地利用结构的生态优劣.     

小麦蚕豆间作对红壤有效磷的影响及其与根际pH值的关系

在云南红壤上采用田间小区试验,通过测定分蘖～拔节期、孕穗～抽穗期、灌浆～乳熟期不同土层深度小麦根际土壤有效磷(available phosphorus)含量和根际pH值,比较研究了小麦蚕豆间作对小麦根际土壤有效磷含量和pH值的影响,探讨了间作小麦根际pH与根际土壤有效磷之间的相互作用.结果表明,与小麦单作相比,小麦蚕豆间作显著地促进了小麦产量的提高.同时,小麦蚕豆间作促进了小麦根际土壤有效磷含量的提高,分蘖～拔节期、孕穗～抽穗期0-10 cm、10-20 cm土层单、间作差异显著;间作显著降低了分蘖～拔节期10-20 cm土层、孕穗～抽穗期0-10 cm、10-20 cm、20-30 cm土层小麦根际土壤pH.分蘖～拔节期、灌浆～乳熟期,单、间作小麦根际土壤有效磷含量与根际pH呈负相关关系.试验表明,在红壤上间作小麦根际土壤有效磷含量的提高与间作降低根际pH有密切关系.     

Effect of nitrogen application during ripening period on photosynthesis and dry matter production and its impact on yield and yield components of semidwarf iniica rice varieties under water culture conditions

Abstract

A water culture pot experiment was conducted to analyze the effects of N application during the ripening period (RP) on photosynthesis, dry matter production, and its impact on grain ripening and yield in two semidwarf indica type varieties viz. Gui Zhao 2 (GZ) and BR3 (BR) compared with a japonica type variety Koganemasari (KO) under four N rates viz. 0 (N₀), 10 (N₁₀), 20 (N₂₀), and 40 (N₄₀) mg L^?1. Results showed that N application enabled to maintain a higher leaf area and delay leaf senescence in both indica and japonica type varieties but the decrease in the rate, of leaf area was higher in the former than in the latter and the rate was reduced with increasing N rates. Flag leaf photosynthesis and SPAD values of N treated plants were higher throughout the RP, showing the presence of a significant correlation either for each variety or all the varieties together. Higher photosynthetic rate was supported by higher leaf chlorophyll (SPAD value basis) content, stomatai conductance, and N concentration in leaf blades. Top dry matter content increased with increasing N rates mainly due to mean leaf area rather than NAR except for BR during RP but it was higher in KO than in GZ and BR. Reduction of shoot weight due to translocation of dry matter to panicles during RP was suppressed by N rates both in GZ and BR while shoot weight increased in the N-treated plants in KO. The dependency of KO on current photosynthates for panicle weight was found to be almost hundred percent while the contribution of stored carbohydrates in shoot before heading to panicle weight in GZ and BR was in the range of 4-27 and 33-54%, respectively and the rest was contributed by current photosynthates. The percentage increased with increasing N rates. Percentage of ripened grains (PRG) increased with increasing N rates in GZ and BR due to the increase in dry matter production and in the photosynthetic rates of apex leaves, despite the larger spikelet number and larger hull size. However, KO showed almost no variation although it had the highest PRG among the varieties. Brown rice yield followed the same pattern as that of PRG in GZ and BR and the highest yield was produced by BR followed by GZ and KO. These results suggest that N application during RP was more effective in increasing yield in the semidwarf indica type varieties than in the japonica type variety.