The distribution and transformation of iron and manganese in soil fractions in a savanna Alfisol under continuous cultivation

Data on the responses of micronutrients in definable soil fractions to cultivation and management are required to design judicious fertilization practices to improve soil fertility in the savanna. Iron and manganese fractions are particularly sensitive to cultivation and management practices. The objectives of this study were to determine the sizes and changes in Fe and Mn fractions in a savanna Alfisol cultivated for 50 years and fertilized with (i) NPK, (ii) farmyard manure (FYM), (iii) FYM + NPK, (iv) a control plot, and (v) a natural site adjacent to the experimental field. The mean concentration of total Fe (Fe_T) ranged from 9.4 g kg^–1 in the surface layer to 45 g kg^–1 in the subsurface layer, whereas total mangenese (Mn_T) concentration ranged from 79 mg kg^–1 in the surface layer to 279 mg kg^–1 in the subsurface layer. The distribution of Fe_T followed the distribution of clay in the soil profile across the field. The distribution of Mn_T did not, however, follow the characteristic depth distribution of clay as observed for Fe_T, suggesting that Mn movement and distribution in this soil might be independent of clay movement and distribution. The concentrations of DTPA extractable Fe and Mn were much higher than the critical levels delineated for soils. Application of FYM increased the concentration of amorphous oxide bound Fe over the natural site and reduced the concentration of residual or inextractable Fe in the soil. Similarly, fertilization with FYM reduced the concentration of residual Mn, and increased the exchangeable, amorphous oxide bound and reducible Mn compared to the natural site. It seems that sole application of FYM or application in combination with NPK rather than NPK alone can mobilize non-labile Mn and Fe sources into labile and plant available forms of Fe and Mn in a savanna Alfisol.     

对复合肥厂污染物排放标准的探讨

对NPK复合肥工厂污染物排放标准的分析表明现行的有关标准不能涵盖其污染物排放的限制.与国外公司NPK复合肥排出物控制指标比较,有不足之处,如缺少氨排放浓度限制的规定值,氟和氨的排放总量控制指标与生产规模大型化之间存在不相适应之处等,均值得与标准制订部门商讨.     

智能化喷浆造粒生产尿基复合肥

叙述了利用尿素制NPK尿素复合肥料生产工艺。该法用尿素浓溶液通过智能化喷浆造粒,实现了尿基复合肥生产智能化。     

Compression testing of granular NPK fertilizers

The crush strength of granular NPK fertilizer has been accurately determined using Instron compression testing equipment. Stress-strain analysis shows a distinctive break point followed by break up of granule fragments. The force required to crush the granules is a function of the granule diameter but the calculated pressure required to crush each granule remained relatively constant. Factors such as moisture ingress and coating oils have been shown to affect granule strength. A direct link between caking of granular fertilizers and crush strength has been established. This revised version was published online in August 2006 with corrections to the Cover Date.     

Quality control measures for developing of 10:20:20 grade fertilizer

It has been shown by agronomists that N.P.K. 10:20:20 is the most suitable fertilizer grade for Pakistan soils to produce high tobacco yields.An attempt was made to manufacture this grade on the pilot scale. Field experiments were conducted for the study of its agronomic efficiency. Physical Quality control measures for the study of its keeping quality were carried out. These studies included hygroscopicity, hardness, caking tendency etc. along with other parameters keeping in view the climatic conditions. No evidence of general superiority was found between the indigenous grade and the imported one.     

Growth response of rubber seedlings to N,P, and K fertilizer in Nigeria

A two-year study (1977/78 and 1978/79) was carried out using GT I seedlings raised in polybags at the Rubber Research Institute of Nigeria (RRIN) main station, to determine the response of rubber seedlings to the application of N, P, K fertilizer. The fertilizers were each applied at three rates as follows: 0, 45 and 90 kg N per ha as sulphate of ammonia; 0, 14.80 and 29.60 kg P per ha as single superphosphate and 0, 9 and 18 kg K per ha as muriate of potash. Stem diameter and height were measured at monthly intervals, while dry matter of tops was estimated at the end of each year of study. P emerged as the single most important nutrient followed by N and K in order of magnitude. Growth response to N and K were enhanced by the presence of P at both levels. The degree of response was related to the level of each nutrient in the soil. Best growth was obtained in the treatments containing all three nutrients. In conclusion, application of fertilizers to rubber seedlings on the soils used, is justified by the growth increases obtained, especially where all three nutrients were applied together.     

具自主知识产权的粒状尿磷铵、尿磷铵钾造粒工艺

介绍了发明专利“制造颗粒状高浓度复合肥尿磷铵和尿磷铵钾的方法”的工艺流程、技术创新点。由于该造粒方法不会增加物料的含水量,与高浓度磷复肥传统的造粒方法相比,取消了干燥、冷却、筛分、破碎、返料以及尾气洗涤等工序,且颗粒强度高(60~80 N)、成粒率高、能耗低(每吨肥料耗电约10kW.h)、投资省,无三废排放,宜在尿基复合肥生产中推广。     

不同施肥处理对小白菜品质及产量的影响

以小白菜为试验材料,利用盆栽方法研究了不同施肥处理对小白菜品质及产量的影响.结果表明,3种施肥处理对小白菜产量影响的顺序为有机无机配施>化肥>有机肥处理;对硝酸盐含量影响的顺序为有机无机配施>有机肥>化肥处理;3种施肥处理间Vc、可溶性蛋白质含量、可溶性糖含量差异达到了显著水平(P<0.05),其中有机无机配施处理含量最高.本试验条件下,有机无机配施既可以提高小白菜产量,又能明显改善小白菜营养品质.