石灰、硅酸钠和羟基磷灰石对烟草吸收镉的影响

为了探讨施用不同钝化剂对烟草吸收富集镉的效果,采用盆栽试验研究了石灰、硅酸钠和羟基磷灰石对Pb-Cd复合污染土壤上的烟草镉吸收富集的影响。结果表明,土壤pH值均随3种钝化剂用量的增大而升高,而土壤有效镉(DTPA-提取)含量则随之降低。土壤有效镉的最大降幅分别为:32 g/kg羟基磷灰石处理(52.4%)16 g/kg石灰处理(37.0%)12.5 g/kg硅酸钠处理(14.1%)。3种钝化剂都降低了烟株各部位镉的含量,其对烟叶镉含量的平均最大降幅分别为87%(16 g/kg石灰处理),74.7%(12.5 g/kg硅酸钠处理)和82.2%(32 g/kg羟基磷灰石处理)。石灰和羟基磷灰石对镉在根-茎之间的转移无显著影响,而硅酸钠则显著降低了镉在根-茎之间的转移。综上,镉污染的植烟土壤可以施用这些钝化剂以降低烟叶中镉的含量。     

熟石灰施用对土壤pH及附子生长发育的影响

[目的]明确熟石灰对附子地酸性土壤的改良作用以及对附子生长发育的影响。[方法]开展盆栽试验研究熟石灰不同施用量对土壤pH、附子生长发育及产量的影响。[结果]不同熟石灰处理(1 350、1 800、2 250 kg/hm~2)均可显著提高土壤pH(P0.05),且不同程度地促进附子出苗、抽茎;中、低用量熟石灰(1 350、1 800 kg/hm~2)能促进附子株高,而高用量(2 250 kg/hm~2)则抑制植株生长;所有处理对附子苗期展叶数均无显著影响;熟石灰用量为1 800 kg/hm~2能提高单株附子产量,而用量为2 250 kg/hm~2能提高附子成活率,促进附子总产量提高。[结论]一定用量的熟石灰能有效调节酸性土壤pH,促进附子生长发育并提高产量。     

整地施肥对I-69杨人工林生长效应的研究

在淮北平原宿县,通过大穴整地、施肥改良砂姜黑土、营造Ⅰ-69杨的五年试验证明,大穴整地当年效应明显(径、高增长19.8%、91.8%);头二年肥效不显;第三年起N肥、有机肥、N×有机肥交互作用效应极显著(材积增加77%),施P+K肥效应较差,N+K肥和N+P肥经济效益较高,投入/产出为1/6.22和1/3.78;材积增加60%和58%。整地加施肥综合效益明显,有效施肥占综合效益85.1%～88.8%。     

掺钢渣的石灰粉煤灰稳定碎石抗压强度的研究

以马鞍山钢铁集团钢渣公司的钢渣为研究对象，分析研究了在半刚性基层材料石灰粉煤灰稳定碎石中掺入细钢渣，用细钢渣部分取代粉煤灰后，混合料无侧限抗压强度的变化情况。试验结果表明，随着细钢渣掺量的增加，石灰粉煤灰稳定碎石混合料的无侧限抗压强度呈先增大后减小的趋势。这说明当细钢渣掺量适当时（钢渣：粉煤灰=1：2），能明显提高石灰粉煤灰稳定碎石混合料的抗压强度，其抗压强度可提高30％，所以从其增强效果来看是比较显著的。     

猪场厌氧出水后续处理效果的测定

针对猪场污水厌氧处理出水的有机物浓度高,后续处理困难的问题,该试验对石灰混凝法处理猪场高浓度厌氧出水的效果进行了测试,并与氧化塘的处理效果进行比较分析。试验中选择了1g／L和5g／L两种石灰投加剂量,对沉淀1、2、3、4、5和6h的净化效果进行取样分析;并对氧化塘猪场污水处理工艺连续取样三天,分析处理效果。结果表明:石灰混凝法投加剂量为5g／L、沉淀时间为5h时,对COD的去除率高达57．8％,明显好于氧化塘的去除效果;但对氨氮的去除率低于氧化塘。石灰混凝法沉淀时间短,基建投资小,可作为猪场污水进入二级处理或深度处理工艺前的可选择性过渡工艺。     

浅谈市政道路石灰土基层施工

笔者从石灰土在道路施工中的重要性出发,分析市政道路石灰土基层施工的前期准备工作,并介绍了市政道路石灰土基层施工工艺流程,最后分析了特殊季节道路石灰土基层施工的注意事项。     

Sugar-Beet-Processing Lime as an Amendment for Low pH Soils

In the Red River Valley, about 385,000 Mg of lime is used to help refine about 39,000 Mg of sugar beets. In a greenhouse study, sugar-beet-processing lime (spent lime; SL), commercial ag lime (AL), and reagent-grade lime (RL) were added to an acidic soil at rates of 0, 1.96, 3.93, and 7.86 Mg ECC ha^?1. Wheat was planted, and aboveground biomass and root masses were determined after 44 d of growth. Soil pH increased the greatest with the highest lime application rates. Incorporation of lime uniformly increased soil pH in the pots, whereas with surface application, soil pH decreased with increasing depth. The SL yielded more aboveground soil biomass and root mass than the AL and RL. Use of SL for increasing soil pH and reducing exchangeable Al in acid soils would be a viable use for this industrial by-product.     

Use of regression analysis for converting quicktest‐measured lime and fertilizer recommendations into actual values based on longer equilibration times

Abstract

Soil tests should produce data useful for making accurate lime and fertilizer recommendations aimed at optimizing chemical conditions for plant growth or providing available nutrient levels sufficient for maximum yields. In order to attain these objectives, we believe, quicktest‐computed rates have to be made equivalent to actual values through a regression adjustment. Although it may not be most desirable to use this adjustment for each new population of soils, it may be worse to try to use a function derived from one group of soils on a second group not well represented by the first.     

二八灰土回填地下粮仓浮力预警试验研究

地下结构的浮力多以阿基米德定律为基础进行计算,未考虑周围回填土体。该文以某地下粮仓为研究对象,考虑周围回填二八灰土的实际工况,分别进行直径为400(模型筒A)、500(模型筒B)、600 mm(模型筒C)的室内缩尺模型试验。试验包含纯水试验和回填二八灰土试验。纯水试验结果表明,以阿基米德定律计算的实际浮力与模型筒自重(包含模型筒上部约束反力所折算自重)的理论浮力基本一致,模型筒A、B、C的实际浮力与理论浮力的误差分别为0.03%、1%、3%。在回填二八灰土试验中,通过缓慢注水,利用位移计、压力传感器监测模型筒位移及模型筒上部的约束反力,分析了模型筒整个上浮过程中位移和约束反力的变化情况。位移突变值滞后于约束反力突变值,压力传感器读数发生明显变化而位移计读数未发生明显变化所测量的水位为警戒水位,压力传感器与位移计读数均发生明显变化所测量的水位为实际起浮水位。以警戒水位和实际起浮水位作为理论计算依据,得出警戒水位和实际起浮水位时模型筒自重(包含模型筒上部约束反力所折算自重)作用下理论抵抗浮力及计算所得的实际抵抗浮力。警戒水位时模型筒A、B、C实际抵抗浮力为理论抵抗浮力的1.93、2.43、1.66倍。实际起浮水位时模型筒A、B、C实际抵抗浮力为理论抵抗浮力的2.15、3.36、2.96倍。从安全储备方面综合考虑,回填工况地下粮仓在预警水位时实际抵抗浮力为理论抵抗浮力的1.5倍,实际起浮水位时抵抗浮力为理论抵抗浮力的2倍,研究结果为今后地下粮仓及其他地下结构的抗浮设计提供参考。     

Effects of Farm Yard Manure and Lime on Cadmium Uptake by Rice Grown in Two Contaminated Soils of Chittagong

A pot experiment was conducted to evaluate the efficiency of farm yard manure （FYM） and lime （calcium carbonate） on reducing the uptake of Cd by rice in two Cd contaminated soils of Chittagong. The effects of farm yard manure, lime and farm yard manure mixed with lime （FYM ＋ Lime） on rice （Oryza sativa L.） growth, Cd uptake by rice and 0.1 N HC1 extractable Cd in soil were investigated. Results showed that addition of lime and farm yard manure mixed with lime significantly decreased 0.1 N HCl extractable Cd in the city sewage soil. Application of farm yard manure significantly decreased Cd concentration in rice in the city sewage soil. Lime and farm yard manure mixed with lime significantly reduced Cd concentration in rice m both the contaminated soils. Lime was more efficient than farm yard manure in reducing the uptake of Cd by rice.