施用硅肥对黑皮甘蔗产量和品质的影响

在广东大宝山缺硅的农田进行了硅肥施用对甘蔗产、质量影响的研究。通过不同施肥量及不同施肥方式的对比研究,结果表明,施用硅肥能显著提高甘蔗(黑皮果蔗)的产量,在硅肥施用量375~1500kg/hm2的区间内,随着硅肥施用量的增加,甘蔗产量增加效果显著,增产幅度为9.6%~26.7%,最高可增产甘蔗40.5 t/hm2;另外,施硅肥能提高甘蔗的糖分,在施用量375~1500 kg/hm2的施用量区间,蔗汁糖分增加的幅度为0.3%~2.0%(绝对值);田间调查还显示,施用硅肥对甘蔗株高及有效茎数影响不大,但能增加甘蔗的茎径0.24~0.64 cm,并使叶片较为直立,生长后期顶叶较为青翠,能使光合作用更为合理;在同样的施肥量下,采用基肥+追肥的施用方式,其增产、提质的效果优于一次性基施的效果。     

乙二胺四乙酸四钠盐缓释微胶囊的制备与表征

The microcapsules with cores of ethylenediamine tetraacetic acid tetrasodium salt (Na4-EDTA) and walls of polyurea were synthesized via an interfacial polycondensation reaction with 2,4-tolylene diisocyanate as an oil-soluble monomer and diethyl triamine as a water-soluble monomer. Various manufacturing parameters, including the amount of emulsifier, agitation speed, stirring time and ratios of the wall materials to core materials, were altered to optimize process variables during the synthesis of microcap-sules, and the effects of these parameters on the characteristics of the microcapsules were examined. The structure, morphology, mean particle size and size distribution were characterized by optical microscope and scanning electron microscopy (SEM), showing that the mean diameter of optimal microspheres was approximately 6 μm, and microcapsules were spherical. In vitro release of Na4-EDTA from these microcapsules was performed in distilled water. Under the optimal preparation conditions, the Na4-EDTA re-lease profiles were biphasic with a burst release followed by a gradual release phase. After an initial burst, a continuous Na4-EDTA release was up to 5-7 days. The optimal synthesis conditions for the microcapsules with stable, good morphology and good con-trolled-release properties were as follows: emulsifier Span-80 10% (by mass), agitation speed 900 r&;#8226;min－1, stirring time 30 min, and the ratio of the wall materials to core materials 0.15.     

土壤中硫形态分析方法

关于土壤中各种形态的硫的分析方法较少。本文整理了一系列土壤中硫形态:水溶性硫、吸附性硫、酸可溶性硫、黄钾铁矾硫、有机硫、单质硫的提取方法及测试方法,希望为环境监测人员提供参考。