有机,无机肥料配合施用对地膜棉田土壤微生物及生化特性的影响

主要研究了有机、无机肥料的配合施用对地膜棉田土壤微生物及生化特性的影响，结果表明：施肥对地膜棉田土壤微生物有较大影响，其中，有机、无机肥料配合施用的影响尤为显著，可增加微生物总数，有益的氮素生理群微生物的数量，降低反硝化细菌的数量。土壤呼吸强度、纤维素分解强度等体现微生物活性的生化过程强度指标均有所增长。     

The estimation of losses of potassium and magnesium from chalky soils in southern England: laboratory studies

Abstract. Ten chalk topsoils (0-25 cm) were repacked into columns in the laboratory. After leaching similar to one year's throughflow in the field, loss of K was equivalent to between 9 and 74kg K/ha. This represented between 3 and 30% of the initial exchangeable K with which loss was poorly correlated. Loss was dependant on the soil solution concentration and was inversely proportional to potassium buffer power.
The loss of magnesium in the same columns was between 10 and 22 kg Mg/ha (6-21% of the initial exchangeable Mg). Magnesium loss was poorly correlated with exchangeable Mg.
When KCl fertilizer was incorporated into the soils, the increase in leaching of potassium was 1–35% of the K addition. Application to the top of the column resulted in less leaching than when the K was incorporated. Leaching of magnesium was increased by up to 5 kg Mg/ha.
Potassium leaching may be delayed by the underlying A/C horizon but pure chalk, with an extremely low buffer power for K, has little ability to retain K. Extremely calcareous topsoils were the most leaky although in practice it is the organic chalk soils on which it is most difficult to attain adequate K levels. On all chalk soils, maintenance of a high K level with K fertilizer is likely to cause unnecessary long-term leaching losses. Annual, rather than biennial, fertilizer applications are to be preferred.     

提高石油库罐区土地利用率的方法

通过罐区单位容量用地面积来探讨罐区容量和油罐规格之间的关系以及油罐的布置方式，给出了降低罐区的ψ值，提高罐区土地利用率的方法。提出储存相同火灾危险性油品的罐区容量应在３００００ｍ＾３以上为宜；一定的罐区容量对应一定的油罐规格，才能节省罐区的用地面积；油罐容积不超过５０００ｍ＾３的罐区，油罐采用双列布置比单列布置节省罐区的用地面积。     

试论中国次生林作业法

论述了中国次生林产生的原因，特殊性，其实质是不平等条件的产物，致使大面积原始林遗到严重破坏，解放后由于采取了“封山育林”的政策，得到了较好的发展。为了进一上提高次生要质量及发展速度，做了多种试验，但以陈大珂，周晓峰等人研究组提出了“栽针保阔－动态经营体系”的理论途径和方法更为系统，并将以推广，对恢复与扩展东北林区的地带性顶极群落－阔叶松林大有裨益，该理论体系，途径，方法经几十年的经营实践，显示其具     

植物叶面积测定方法的比较研究

以两个不同品种的大豆叶片为研究对象，采用了不同的测定方法测定叶面积，分析并指出各种测定方法的优缺点，为在不同测定条件和实验目的要求下选择不同的叶面积测定方法提供依据，也为研究人员提供更加准确、快速、简便和经济的测定方法和依据。     

回归分析法在累积流量测量中的应用

在非定点使用标准表的标准装置中,进行累积流量的测量时要用到流量计的仪表系数。通过实例计算介绍了另一种求得仪表系数的方法,即回归分析法。利用这种方法求得的流量计的仪表系数,由于减少了人为的误差,因此,大大提高了计算整个累积流量测量过程总液量的准确度,同时提高了工作效率。     

Use of an electromagnetic technique to determine sodicity in saline-sodic soils

Soil sodicity is an increasing problem in arid‐land irrigated soils that decreases soil permeability and crop production and increases soil erosion. The first step towards the control of sodic soils is the accurate diagnosis of the severity and spatial extent of the problem. Rapid identification and large‐scale mapping of sodium‐affected land will help to improve sodicity management. We evaluated the effectiveness of electromagnetic induction (EM) measurements in identifying, characterizing and mapping the spatial variability of sodicity in five saline‐sodic agricultural fields in Navarre (Spain). Each field was sampled at three 30‐cm soil depth increments at 10–30 sites for a total of 267 soil samples. The number of Geonics‐EM38 measurements in each field varied between 161 and 558, for a total of 1258 ECa (apparent electrical conductivity) readings. Multiple linear regression models established for each field predicted the average profile ECe (electrical conductivity of the saturation extract) and SAR (sodium adsorption ratio of the saturation extract) from ECa. Despite the lack of a direct causal relationship between ECa and SAR, EM measurements can be satisfactorily used for characterizing the spatial distribution of soil sodicity if ECe and SAR are significantly auto‐correlated. These results provide ancillary support for using EM measurements to indirectly characterize the spatial distribution of saline‐sodic soils. More research is needed to elucidate the usefulness of EM measurements in identifying soil sodicity in a wider range of salt and/or sodium‐affected soils.     

Effects of different land use types on infiltration capacity in a catchment in the highlands of Ethiopia

Infiltration capacity is an important variable for understanding and predicting a range of soil processes. This study investigated for different slope positions the effects of forest conversion to cultivation and grazing on soil infiltration capacity. Infiltration capacity was measured in the field in each land use type using a double‐ring infiltrometer. A total of 108 soil samples (3 slope positions × 3 land use types × 4 soil profiles × 3 soil depths) were collected to determine the variables that affect infiltration capacity viz. particle size distribution, organic carbon content, dry bulk density and soil moisture content. The results showed that in the cultivated and grazed land compared with forest, infiltration capacity and soil moisture content were 70 and 45% smaller respectively, and dry bulk density was 13–20% larger. Changes in soil structure caused by surface soil compaction because of tillage and animal trampling coupled with a smaller soil organic carbon content, are likely to be the principal factors causing the decline in infiltration capacity and soil moisture content after conversion of forest to cultivation and grazing.     

Reclamation of saline‐sodic soil under a rice–wheat system by horizontal surface flushing

Saline sodic soil with a high content of soluble carbonates is one of the important agricultural soils on the Central Indo‐Gangetic plains and elsewhere. Conventional reclamation procedures using gypsum application followed by vertical leaching (GC) is uneconomic; high ECe and precipitation of applied gypsum, reacting with soluble carbonates, reduce the efficacy of gypsum in these soils. This paper reports results from a project designed to evaluate reclamation by irrigation of the ploughed soil and turning of soil with a power tiller followed by flushing of standing water after 24 h, a second flushing after 7 days and subsequent application of gypsum and vertical leaching (GF2). Average rice and wheat production after GF2 significantly increased (25 and 62%, respectively) over the conventional practice. Compared with conventional treatment, GF2 significantly reduced the ECe and SAR of the soil and improved physical properties such as ζ‐potential, dispersible clay content, water stable aggregates expressed as MWD, and saturated hydraulic conductivity. Split application of gypsum between flushing (GF1/2 and GF2/3) gave similar results to GF2 in terms of soil amelioration and crop production.     

《企业管理》教学案例分析方法刍议

根据多年进行《企业管理》案例教学的体会,阐述了教学案例的特点、教学案例分析与管理实例操作之差异以及教学案例的分析方法。