测定土壤有机质需要注意的几个问题

通过工作实践,对土壤有机质测定采用的重铬酸钾容量法在具体操作中应注意的几个问题做出详细阐述,规范土壤有机质测定的操作规程。     

施磷量对旱地小麦氮磷钾和干物质积累及产量的影响

针对目前农业生产中存在的施肥增产效应下降问题,研究了磷肥用量对冬小麦养分、氮磷钾和干物质积累及产量的影响,以期为高产高效施肥提供依据.在黄土高原旱地进行田间试验,设不施磷,施磷P2O5 50kg/hm2(不足)、P2O5 100 kg/hm2(适量)和P2O5 150 kg/hm2(高量)4个水平,在不同生长期采样测定...     

丛枝菌根对油桐幼苗生长和氮磷吸收的影响

通过非灭菌土盆栽接种试验,观察了Glomus mosseae(GM)、G.intraradices(GI)、G.aggregatum(GA)和G.atunicatum(GE)4种AM真菌对油桐幼苗生长和氮磷吸收的影响,结果表明接种GM、GI和GE后菌根侵染率显著提高,侵染率分别为77.4%、92.3%和96.7%,比对照分别提高20.4%、43.5%、50.4%。接种GA与对照无显著差异;接种GM和GI后植株的干质量增加,而接种GA和GE对全株及各器官干质量影响不明显;接种4种真菌对油桐幼苗的氮素营养影响不大;接种GM、GI和GE显著提高了根部磷含量。综合考虑,接种GM效果最好。     

猕猴桃对硒的吸收、分布、积累特性的研究

大田条件下,给中华猕猴桃施以浓度分别为0．15、0．3、0．5mg／培的Na：SeO,溶液,在盛花期每30d测定果实和叶对硒的积累情况;果实成熟期测定猕猴桃各部位含硒量以及鲜重、可溶性糖含量、可溶固形物和Vc含量;结果显示：施硒后,猕猴桃各部分含硒量显著升高,并且硒在猕猴桃中累计顺序为根〉叶〉花〉果实。果实鲜重、可溶性糖含量、可溶固形物和％含量随着硒浓度的增大而升高,然而在高浓度的硒（≥0．5rag／kg）水平下,受到不同程度的抑制。施硒显著提高了猕猴桃对硒的吸收、分布、积累和改善了果实的品质。     

Use of the BCR three-step sequential extraction procedure for the study of the partitioning of Cd, Pb and Zn in various soil samples

A slightly modified three-step sequential extraction procedure proposed by the Community Bureau of Reference (BCR) for analysis of sediments was successfully applied to soil samples. Contaminated soil samples from the lead and zinc mining area in the Mezica valley (Slovenia) and natural soils from a non-industrial area were analysed. The total concentrations of Cd, Pb and Zn and their concentrations in fractions after extraction were determined by flame or electrothermal atomic absorption spectrometry (FAAS, ETAAS). Total metal concentrations in natural soils ranged from 0.3 to 2.6 mg kg^-1 for Cd, from 20 to 45 mg kg^-1 for Pb and from 70 to 140 mg kg^-1 for Zn, while these concentrations ranged from 0.5 to 35 mg kg^-1 for Cd, from 200 to 10000 mg kg^-1 for Pb and from 140 to 1500 mg kg^-1 for Zn in soils from contaminated areas. The results of the partitioning study applying the slightly modified BCR three-step extraction procedure indicate that Cd, Pb and Zn in natural soils prevails mostly in sparingly soluble fractions. Cd in natural soils is bound mainly to Fe and Mn oxides and hydroxides, Pb to organic matter, sulphides and silicates, while Zn is predominantly bound to silicates. In contaminated soils, Cd, Pb and Zn are distributed between the easily and sparingly soluble fractions. Due to the high total Cd, Pb and Zn concentrations in contaminated soil close to the smelter, ! and their high proportions in the easily soluble fraction (80% of Cd, 50% of Pb and 70% of Zn), the soil around smelters represents an environmental hazard.     

聚合物包膜肥料中钾素释放特征及其模拟

以水和水饱和石英砂为介质，研究了2种聚合物包膜肥料中钾素的释放特征。结果表明，钾素释放主要受温度影响，同时还受到颗粒大小和形态的影响；在水饱和石英砂中溶出与在水中溶出差别不大。采用水为介质，以一聚合物包膜肥料养分释放的理论模型为基础，对影响聚合物包膜肥料钾素释放的因素进行了研究，并进行了灵敏性检验。结果表明，温度越高、包膜的厚度和颗粒半径越小时钾素释放越快，且试验结果和模拟结果达到极显著的相关性；模拟结果比实际结果明显偏低，但表现出了较好灵敏性和相关性，是一个具有理论基础和应用潜力的聚合物包膜肥料养分释放模型。     

Effects of Foliar Fertilization on Incidence of Berry Shrivel and Bunch Stem Necrosis in Vitis vinifera L. CVS ‘Pinot Blanc’ and ‘Zweigelt’

Berry shrivel and bunch stem necrosis are the economically most important physiological disorders of grapevine. The nutritional status of the plant is considered as one of the main elicitors for the occurrence of these disorders. For foliar fertilization trials, two vineyards that had previously been affected by both diseases were selected in Southwest Germany, one with the variety ‘Zweigelt’ and one with Pinot Blanc. By the use of potassium, magnesium, and calcium foliar fertilizers, a rapid increase of different nutrients in the plants should be caused and the effects on the diseases observed. In 2010, no significant differences in the fertilization treatments were found for both varieties. In ‘Pinot Blanc’, significantly more berries were affected by berry shrivel in 2011 in plots treated with calcium fertilizer compared to those treated with potassium and magnesium. Plots with magnesium fertilizer showed significantly less berries affected by berry shrivel than the untreated control.     

施硒对茄子吸收转化硒和品质的影响

盆栽试验结果表明,土壤施硒(0.15、0.60、3.00mg/kg)条件下,茄子的含硒量随施硒量的增加而显著增加。当施硒量为0.60和3.00mg/kg时,茄子无机硒转化成有机硒的比率下降,显著提高了茄子粗蛋白、粗脂肪和还原糖含量,增加了茄子的必需氨基酸总量,改善了茄子的品质。土壤施硒显著增加了茄子蛋氨酸、胱氨酸和丝氨酸的含量,但谷氨酸和脯氨酸的含量显著降低。     

不同土壤和氮钾肥配比对莴笋的营养效应研究

通过田间小区试验研究了不同N、K肥料配比对酸性和碱性土壤上两个莴笋品种(科兴 3 号和双尖莴笋)产量及品质的影响.结果表明,不同土壤上施用不同N、K配比肥料对双尖莴笋和科兴 3 号的产量影响不同.在酸性土壤上,对照(N15K10)是适宜两种莴笋高产的最佳N、K肥配比处理.在碱性土壤上种植双尖莴笋时,可以考虑在对照基础上适当地降低N肥用量.在碱性土壤上两种莴笋的产量均高于酸性土壤.减N和增K处理有利于降低莴笋的硝酸盐含量.在酸性土壤上莴笋中的硝酸盐含量高于碱性土壤.莴笋采收后期茎的硝酸盐含量高于叶片.不同施肥处理对两种土壤上科兴3号和双尖莴笋营养品质的作用不一致.在酸性土壤上增施K肥或提高N肥的用量对莴笋营养品质的改善更有效果.莴笋的Vc含量以叶片＞茎,且酸性土壤＞碱性土壤.除双尖莴笋在增K处理(N15K15、N20K15)中茎的可溶性糖含量表现为酸性土＜碱性土以外,其他处理莴笋茎叶中的可溶性糖均为酸性土＞碱性土.不同处理莴笋的氨基酸含量均表现为茎＞叶.