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长期施用有机肥对紫色水稻土铁锰铜锌形态的影响 总被引:55,自引:8,他引:47
以长期定位试验为基本材料 ,研究了 9年连续施用有机肥对紫色水稻土铁、锰、铜、锌形态的影响。结果表明 ,有机肥是土壤铁、锰、铜、锌的良好给源。紫色水稻土长期施用有机肥与单施化肥比较 ,土壤中的全铁、全锰变化不大 ,全锌提高了 5.5%~ 30.0% ,交换态铁、碳酸盐结合态铁、有机态铁、无定形结合态铁分别提高了1.5%~12.7%、2.4%~8.9%、11.6%~19.5%、32.5%~72.5%。锰、锌的各形态数量均有不同程度的增加。同时 ,长期施用有机肥增大了土壤铜的消耗 ,全铜含量有下降的趋势。 相似文献
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硼的吸附-解吸对土壤表面性质的影响 总被引:5,自引:1,他引:5
对三种不同类型土壤———棕红壤、黄棕壤、灰潮土在特定条件下的电荷零点(PZC) :ck—PZC(无硼 )、ads—PZC(硼吸附 )和des—PZC(硼解吸 )的研究发现 ,棕红壤和黄棕壤的ads—PZC与其ck—PZC相比 ,都有较为明显的下降。灰潮土 ,由于本身碳酸盐的缓冲作用 ,其ads—PZC与ck—PZC几乎相等。在硼吸附发生后 ,3种供试土壤的des—PZC较之它们的ads—PZC ,改变甚小 ,但这时灰潮土却保持强劲吸附电位离子的趋势 ,其吸附H 离子数量是棕红壤和黄棕壤的 2倍 ,表明在灰潮土上 ,原先被土壤胶体吸附的硼这时才显示利于电位离子的吸附。研究还表明 ,硼在酸性土壤中的吸附会引起 1 0倍量的质子的吸附 相似文献
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水网地区水稻土的含硒量及根外施硒对糙米硒含量的影响 总被引:12,自引:0,他引:12
本文通过对嘉善县平原水稻土硒含量特征和该区水稻硒含量之间关系的调查研究表明:(1)嘉善县平原水稻土,水溶态硒含量低于一般水稻土水溶态硒的临界值(0.010μg/g),这与该区的土壤母质、地形等因素相关;(2)低硒水稻土了水稻对硒的吸收积累,因此该县出产的稻米硒含量亦普遍较低,平均含硒量低于粮食硒的正常含量范围(0.040~0.070μg/g);(3)水稻地上各部分含硒量存在差异,糠、秸杆中的含硒量 相似文献
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杂交水稻新组合汕优广12的父本广12,花时在9~13时,盛花在10~12时,峰值出现在11时,单株花期长达13天。母本珍汕97A花时分散。制种花时相遇在每天9~13时,集中在11~12时。花时全遇时,结实率早造达45.88%,晚造达43.75%。花时相隔48小时授粉,结实率仍可达20%。这一特征,为制种夺高产提供了生物学依据。 相似文献
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研究分析了7个同核异质不育系和保持系花药中的酯酶同工酶和过氧化物酶同工酶,结果表明:在这两种同工酶的酶谱中,有些谱带是不育系与保持系共有的,不受雄配子的育性和胞质差异的影响。有些谱带则伴随雄配子的败育而出现(或缺失),其余谱带组分,则因胞质背景的不同而存在差异。据此认为,可以通过同工酶酶谱分析,对细胞质进行遗传鉴定。 相似文献
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The State of Bahrain lies in the arid zone on the southern side of the Arabian Gulf. The factors influencing soil formation on the Islands are examined and an account given of the soils. These can be placed in four groups: Solonchaks, Regosols, Yermosols and Fluvisols. The Solonchaks of the northern plain contain unprecedented amounts of gypsum which, in the absence of leaching, give rise to a variety of morphological features. The distribution of Regosols, Yermosols and Fluvisols can be related closely to physiographical location throughout the country. 相似文献
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G. D. TOWNER 《European Journal of Soil Science》1980,31(4):607-621
The time taken for a tensiometer to reach equilibrium with the soil-water pressure is a function not only of the tensiometer characteristics but also of the soil-water transport properties. When. in an appropriate system of units. the numerical value of the conductance of the tensiometer cup is small compared with that of the hydraulic conductivity of the soil, and the sensitivity of the pressure ‘gauge’ is large compared with the differential water capacity of the soil. then the precision of the measurements is such that the observed response may be indistinguishable from that of a tensiometer in bulk water. referred to as ‘tensiometer limited’. The theory developed in this paper for a hemispherical tensiometer cup shows that tensiometer-limited conditions can be achieved in practice. Moreover. such conditions would often correspond to a rapid response system. It is suggested that it might be advantageous in the design of a field recording system to choose a tensiometer-limited system even if it is not the fastest realisable one in order that its response is completely predictable from the known tensiometer characteristics. independent of the unknown soil properties. which may be changing. 相似文献
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K. M. GOH 《European Journal of Soil Science》1978,29(3):340-349
Peat samples from Timaru Downs, New Zealand were subjected to a wide range of chemical treatments before radiocarbon assay. A step wise procedure was used in which each sample was radiocarbon dated before and after the treatments were applied. The criterion adopted for indicating the removal of young contaminants and thus resulting in the improvement in the reliability of radiocarbon dates is the increase in the radiocarbon age of the sample after treatment. When peat samples were radiocarbon dated without prior chemical treatments the results could not be used to accurately date the time of formation because of young contaminants. Contaminants could be removed by chemical treatment of peats with mineral acids, particularly 70% HNO3 for the very old peat sample. The improvement brought about by acid treatment was greater than that from the classical humus extraction and fractionation method. 相似文献
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丛枝菌根根外菌丝对不同形态氮素的吸收能力 总被引:4,自引:0,他引:4
本试验以玉米为宿主植物,以Glomus mosseae和Glomus intraradices为接种剂,采用空气隔板分室-半液培系统,在植株收获前48 h向菌丝室供应15N标记的不同形态氮素,探讨丛枝菌根根外菌丝吸收传递不同形态氮素的能力。结果表明,丛枝菌根根外菌丝吸收传递15N能力因菌种和氮素形态而异。丛枝菌根真菌G.intraradices吸收传递15N的能力高于G.mosseae,根外菌丝吸收传递不同形态15N的能力为15NH4+>15N-Gln>15N-Gly>15NO3-。根外菌丝吸收传递的15N对植株氮营养的贡献仅为0.004%~0.032%。 相似文献
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H. LAUDELOUT L. GERMAIN P. F. CHABALIER C. N. CHIANG 《European Journal of Soil Science》1977,28(2):329-339
An estimate is given of nitrogen losses which could occur through chemical decomposition of nitrite formed by nitrification of ammonium in acid tropical soils. Experiments on the rate of disappearance of nitrite were carried out in acid buffers as well as in soil samples. Numerical solutions of a system of differential equations describe the nitrification process and the chemical denitrification reaction. Up to 50 per cent of added ammonium nitrogen may be lost in an acid soil when nitrification occurs at temperatures prevailing in the humid tropics. 相似文献
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本文从硬度与其它机械性能之间的关系,特别是从硬度对磨粒磨损的影响方面论证了硬度是各机械性能的一个综合性能指标。硬度及其它机械性能都是金属内部组织结构的反映,从金属的组织对磨粒磨损的影响也能得出上述结论。因此,只要预先知道金属组织转变的倾向,就可以用测量硬度的方法研究组织转变的发展情况。从这点出发,配合显微组织观察,对一种低碳合金结构钢的中温转变进行了研究,作出了这种钢的一些温度下的等温转变动力学曲线以及该钢的中温转变的TTT图。 相似文献
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油-稻轮作条件下土壤硫形态消长规律的研究 总被引:1,自引:0,他引:1
土壤无机硫主要是水溶和吸附态SO42-,它能被作物直接吸收。有机硫是作物利用硫的主要来源,分为HI还原有机硫(硫酸酯)、碳键硫(C-S)和惰性硫。有机硫只有转化为SO42-后才能为作物吸收[1]。土壤硫形态转化规律室内培养和盆栽研究较多[1,2],田间试验研究较少,国外探讨了油菜一休闲制中土壤硫形态转化规律[3]。水一早轮作制是中国主要轮作制之一,该轮作制中土壤处于干一湿交替之中,土壤硫转化规律可能有其特异性。本研究选择油一稻轮作制为研究对象,研究土壤硫形态消长和分配规律。其结果将为评价土壤供硫能力和了解土壤硫肥力维持机制提供依据。 相似文献