铅胁迫下菲白竹的矿质营养吸收和分配

随着矿产、化工、冶金等工业排放的"三废"剧增以及汽车尾气排放量的增加,人类生存环境中的土壤、水体以及空气受重金属污染现象日趋严重,有些重金属通过食物链在人体内蓄积,严重危害人体健康(Kambhampati et al.,2003).铅是一种常见的重金属,全球每年消耗量约为400万t,但仅有1/4得到回收利用,其余大部分都以不同形式进入环境引起污染(李建正,2006).     

9种壳斗科树种坚果3种矿质元素及Vc含量分析

壳斗科(Fagaceae)主要分布在亚洲东南部,全球约900种。我国大多数地区通常把壳斗科植物的坚果都称为橡实,有些省区仅将栎属(Qucercus L.)树种的坚果称之为橡实,而李世华等认为橡实又叫橡子;显然,橡实或橡子均指壳斗科植物的坚果。     

土壤透气性及粘土颗粒比表面积与粘土颗粒粒度分布分形维数关系

采用数字显微系统测定了部分华南地区土壤中粘土颗粒粒径分布分形维数值,提出了土壤中粘土颗粒群粒度分布分形维数的几何法计算模型,并就这种分形维数与土壤比表面积和土壤透气性等性质的相互关系作了初步探讨。结果表明,采用数字显微系统测定的粘土颗粒粒径分布分形维数值介于2.2708到2.9483之间,与常规方法测定结果吻合;含砂较多的土壤样品,BET比表面积和Blaine透气时间随粒度分布分形维数值增大而减小;含粘粒较多的土壤样品,BET比表面积和Blaine透气时间同随粒度分布分形维数值增大而增大。     

青海省东部山区旱作农田土壤团聚体特征研究

比较了青海省东部山区垂直梯度分布的三种旱作农田土壤(黑钙土、栗钙土、灰钙土),在0~60 cm土层的不同粒级土壤风干团聚体和水稳性团聚体含量间的差异,并结合其它土壤质量指标(有机质、粘粒)对不同土壤结构和抗侵蚀能力进行了综合评价。结果表明,>0.25mm风干团聚体、>0.25mm水稳性团聚体含量和土壤有机质含量与土壤类型间有密切关系。均表现为黑钙土>栗钙土>灰钙土。黑钙土和栗钙土的土壤有机质含量与>0.25mm水稳性团聚体间存在显著正相关关系(P<0.05),灰钙土则无明显相关性;三种土壤粘粒含量与>0.25mm风干团聚体和0.25mm水稳性团聚体含量间无明显相关性。各项指标综合比较,三种土壤抗侵蚀能力大小为:黑钙土>栗钙土>灰钙土。     

氮肥施用对冬小麦籽粒产量和氮素表观损失的影响

Excessive nitrogen （N） fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content （Nmin） in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels （average 212 kg N ha^-1）. The average optimum N rate was 96 kg N ha^-1 for the five sites with low initial soil Nmin （average 155 kg N ha^-1） before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha^-1, whereas the farmers＇ conventional N application rate resulted in losses of more than 100 kg N ha^-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields.     

田林老山中山杉木人工林生产力及营养元素循环的研究

广西田林县老山林场中山区气候冷凉潮湿,土壤肥力较高,能满足杉木速生要求。17年生杉木人工林乔木层的生物量达138.46t/ha,平均净生产量为8.15t/ha·a,与杉木中心产区相当。乔木层对N,P,K,Ca,Mg5种营养元素的吸收量为224.04kg/ha·a,其中42.3％存留在林木层,42.5％通过凋落物,15.2％通过降雨淋洗归还土壤。通过凋落物归还是N,P,Ca,Mg归还的主要途径,K的归还主要通过降雨淋洗;K,Ca,Mg的循环系数较大,分别达到0.58,0.68和0.60;N,P相对较小,分别为0.48和0.33。林木正处于生长旺盛阶段,杉木对5种营养元素的吸收量、存留量和归还量以及循环系数都有较高水平,生物量积累也较大。     

糯米糍荔枝叶片矿质养分含量充足范围的确定

对深圳市4个典型丰产园糯米糍荔枝叶片7种矿质养分(氮、磷、钾、钙、镁、锌和硼)含量的统计分析表明:采样地点和生育时期均对叶片营养元素含量有显著的影响。四个关键生育时期(末次秋梢老熟期、花芽形态分化期、谢花期和果实成熟期)的单株样与混合(多株)样的供试矿质养分含量之间大部分没有显著差异。本研究根据丰产园糯米糍荔枝叶片混合样的分析结果提出了7种矿质养分的充足含量范围。     

奥普明与螯合微量元素对养猪生产的影响

主要微量元素的功用 微量元素如何调节动物的机体代谢,在许多方面尚不清楚,以下是我们已经了解到的部分内容,但什么是生长或繁殖的 最佳需要量,哪种化学结合最易被动物吸收利用,至今只有有限的研究资料,这为我们的生产带来许多不确定因素。特别 是重金属铜超量不仅能引发动物自身的毒害作用,同时还会造成严重的环境污染,甚至是肉品自身的污染。有限的研究资 料显示,微量元素的利用对动物健康作用显著,选择正确与否将对动物的繁殖性能及生长性能有显著的影响。     

Growth and Nutritional Disorders of Eggplant Cultivated in Nutrients Solutions with Suppressed Macronutrients

The objective was to evaluate the effects of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of eggplants. The treatments were complete nutrients solution and solutions with nutrient omission: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The experiment was carried out under greenhouse conditions with three replicates in a completely random design. Plant height, number of leaves per plant, leaf area, relative chlorophyll index, photosynthesis rate, stomatal conductance, dry matter, concentration levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Omitting elements interfered in the concentration of elements in the various plant tissues and this had as consequences limited vegetative growth, reduced dry matter and led to the development of the typical deficiency symptoms of each element. Although potassium was the most demanded of all elements, nitrogen and calcium were the most growth limiting ones.