Phosphorus content in soil, uptake by plants and balance in three European long-term field experiments

The fate of phosphorus (P) derived from mineral fertilisers and organic manures, and the effective P balance, have been assessed in three long-term field experiments at Rothamsted (UK), Bad Lauchstaedt (Germany) and Skierniewice (Poland). This paper discusses the plant availability, uptake and overall utilisation of P over the last 30 years, based on soil test P availability indices and crop analyses determined by the standard methods used in each of the three countries. The data suggest that differences in soil type significantly influence the dynamics of P at the three locations, but most significantly between a loess Chernozem at Bad Lauchstaedt with a high organic matter content and the soils at the other two locations which have a low organic matter content. The application of P either as inorganic fertiliser or organic manure had a considerable influence on the availablity, uptake, leaching or fixing of P, but the crop recovery rate of P from mineral fertiliser did not exceed 35% with the smallest recovery (average 18%) occurring in the soil with the highest clay content at Rothamsted. At Bad Lauchstaedt and Rothamsted the most efficient utilisation of P (averages of 47% and 37%, respectively) was from soils treated with farmyard manure (FYM), with the greater quantity of P either leached or fixed (8 and 25 kg ha^-1 y^-1, respectively) occurring in soils treated with superphosphate. At Skierniewice, however, the reverse was true. Overall, the most efficient crop utilisation from mineral P (30% average) was from the loamy sand at Skierniewice. P balances for the three locations show that quantitatively, for the same P input, the amount of P either leached from or fixed in the plough layer of Broadbalk field, Rothamsted, was 2–3 times greater than at Skierniewice and 3–6 times greater than at Bad Lauchstaedt. The results suggest that differences in the soil physico-chemical properties, climate, the availability of other major nutrients, and the form in which P is applied, all influence the effectiveness of P fertilisation and P balance. The investigation highlights the importance of maintaining long-term field experiments and archived soil and crop samples on a world-wide basis for understanding nutrient cycling and fertility dynamics.     

二灰改良土在高速铁路路基中的应用研究

基于高速铁路路基对填料的严格要求 ,改良土成为高速铁路不可回避的问题。结合秦沈快速铁路工程实际 ,进行了石灰粉煤灰改良土的物理力学特性试验。试验表明 ,二灰改良土用作高速铁路路基基床底层材料是可行的     

锌肥有效施用的土壤条件研究

通过田间试验、相关分析研究了松嫩平原黑土和黑钙土的锌肥有效施用条件。结果表明 :当土壤 p H>7.2、石灰含量 >3.9%、砂粒含量 >40 %、代换量 <15 cm ol/ kg、有机质含量 <2 %、土壤有效锌含量低于缺锌临界值0 .8m g/ kg时 ,施用锌肥具有明显的增产效果。而在高磷情况下会降低土壤锌有效性 ,易引起玉米缺锌加重。吉单10 1和四单 8两个玉米品种对锌缺乏最为敏感。     

环境因子对土壤水分蒸散的影响

在有作物生长的条件下，土壤散失到大气中的水分主要通过土壤表面蒸发和作物叶面蒸腾两种方式进行，二者之和称为土壤水分蒸散。由于作物冠层的遮荫作用，作物覆盖下土壤水分的蒸发强度与裸土情况下显然不同。本文建立了土壤水分蒸散率的计算公式，并对几个环境因子的影响进行了讨论。计算结果表明，冠层净辐射强度和空气饱和差对蒸散率影响较大，而气温和风速的影响相对较小。当冠层净辐射强度和空气饱和差增大时，蒸散率和日蒸散总量的增加均较为明显。另外，作物的叶面积指数对蒸散也有较大的影响，同时它对蒸发和蒸腾在蒸散中所占的比重影响很大，叶面积指数增大时，叶面蒸腾所占的份额增大，而蒸发所占的份额相应地减小。     

稳定分析中的几个土压力问题

在稳定分析中,土压力计算是荷载计算经常遇到的一个方面。本文主要针对稳定分析中土压力方面的问题进行了探讨,总结和提出了处理土压力问题的一般思路和方法。     

土壤污染及其防治研究

通过分析和了解污染物进入土壤的途径、土壤污染物的种类、危害及土壤污染防治的特点,提出土壤污染的防治措施与对策。     

土壤高温储热热湿迁移过程的初步研究

初步建立了土壤高温储热热湿迁移过程的数学模型,并进行了数值求解.结果表明,土壤热湿迁移过程中的湿度场稳定时间明显滞后于温度场,且与土壤类型和水力传导特性等有关.对于水力传导性较差的土壤,在高温储热初期,靠近热源的地方容易产生湿份聚集,使得湿度曲线出现一个短期峰值.与低温储热相比,土壤高温储热时湿度迁移对温度场的影响较大,温度场呈整体降低趋势,降低幅度顺序为:砂土>壤土>粘土.在该文模拟条件下,粘土的热湿迁移过程对于初始湿度的变化不敏感,而砂土的热湿迁移过程则依赖于初始湿度,且影响程度随着初始湿度的增加而增大.     

重金属污染土壤的植物修复研究进展

土壤污染是全球面临的一个亟待解决的环境问题。近年来,植物修复技术迅速发展为主要用于清除土壤重金属污染的生态技术。文章介绍了土壤重金属污染的特性、危害及其治理方法。重点介绍了植物修复技术,并探讨了今后植物修复技术的发展前景。     

丙炔(噁)草酮在马铃薯和土壤中的残留及安全使用评价

[方法]采用田间试验方法,对丙炔(噁)草酮在马铃薯植株及土壤中的残留消解动态及最终残留量进行了研究,用气相色谱电子捕获检测器进行定量分析.[结果]消解动态试验结果表明:丙炔(噁)草酮在土壤中的半衰期为12.9～13.6 d,在马铃薯植株中原始沉积量较低,无法计算半衰期;最终残留量试验结果表明:80％丙炔(噁)草酮可湿性粉剂按施药剂量为216、324 g a.i./hm2,喷药1次,收获期马铃薯块茎中丙炔(噁)草酮的残留量均未检出,土壤中丙炔(噁)草酮残留量为0.0393～0.0695 mg/kg.[结论]推荐80％丙炔(噁)草酮可湿性粉剂在马铃薯上使用安全间隔期为收获期.     

论一种含调节剂的生态肥料的应用

论述了一种含调节剂的生态肥料的应用以及主要广泛对土壤施用化肥的状况下,对农作物生长的影响,对化肥功能的作用以及对土壤生态环境的影响.