Investigation on the use of macro- and micro-nutrients to improve maize yield in South Western Nigeria

Investigation into the use of macro- and micro-nutrients to increase maize yield was conducted in both the glasshouse and in the field. The glasshouse studies involved ten soil series commonly cultivated to maize in South Western Nigeria, while the field studies were conducted on one soil at Ibadan.Dry matter yield increased above the control with a single application of N, P, K, Ca, Mg, Fe, Cu, Zn and Mn, suggesting that most of the soils in the South Western Nigeria require additions of each of these elements for increased maize production. The size of the response to each element varied from series to series. Soils which were high in organic matter (over 3%) required the lowest N dressings for optimum dry matter yield of maize.In the field studies, a fertilizer combination which included N, P, K, Mg and the micro nutrients Fe, Cu and Zn gave a higher relative yield than the single application of N, P, K, and a combination of NP, NK, Pk or NPK.In the South West Zone of Nigeria, there is no soil testing programme and fertilizers applied by farmers and researchers have not increased yields as expected. Average maize yield on farmers' field is less than 1000 kgha^–1 while on research stations it is 2500 kgha^–1. When compared with 7000 kgha^–1 in U.S.A., these yields are still very low.Different recommendations for the major plant nutrients have been made by many workers in the South West zone based on fertilizer trials [1, 5, 8, 13, 16].None of the recommendations have included the micronutrients and secondary nutrients and the objective of this project was to supply relevant information on this important aspect.     

Integrating legumes to improve N cycling on smallholder farms in sub-humid Zimbabwe: resource quality, biophysical and environmental limitations

The release of mineral-N in soil from plant residues is regulated by their ‘quality’ or chemical composition. Legume materials used by farmers in southern Africa are often in the form of litter with N concentration <2%. We investigated the decomposition of Sesbania sesban and Acacia angustissima litter in the field using litterbags, and N mineralization of a range of legume materials using a leaching tube incubation method in the laboratory. The mass loss of the litter could be described using a modified exponential decay model: Y = (Y ₀−Q)e^−kt + Q. The relative decomposition constants for Sesbania and Acacia litter were 0.053 and 0.039 d⁻¹, respectively. The % N mineralized from fresh Sesbania prunings was 55% compared with only 27% for the Sesbania litter after 120 days of incubation under leaching conditions. During the same period, fresh prunings of Acacia released only 12% of the added N while Acacia litter released 9%. Despite the large differences in N concentration between Acacia prunings and its litter, the total mineralized N was similar, as mineralization from prunings was depressed by the highly active polyphenols. While N supply may be poor, these slow decomposing litter materials are potentially useful for maintaining soil organic matter in smallholder farms. In two field experiments with contrasting soil texture, Sesbania, Acacia and Cajanus produced large amounts of biomass (>5 Mg ha⁻¹) and improved N cycling significantly (>150 kg N ha⁻¹) on the clay loam soil, but adapted poorly on the sandier soil. There was a rapid N accumulation in the topsoil at the beginning of the rains in plots where large amounts of Sesbania or Acacia biomass had been incorporated. Despite the wide differences in resource quality between these two, there was virtually no difference in N availability in the field as this was, among other factors, confounded by the quantity of N added. A substantial amount of the nitrate was leached to greater than 0.4 m depth within a three-week period. Also, the incidence of pests in the first season, and drought in the second season resulted in poor nitrogen use efficiency. Our measurements of gaseous N losses in the field confirmed that N₂O emissions were <0.5 kg N ha⁻¹. As we had measurements of all major N flows, we were able to construct overall N budgets for the improved fallow – maize rotation systems. These budgets indicated that, in a normal rainfall season with no major pest problems, reducing nitrate leaching would be the single largest challenge to increased N recovery of added organic N in the light textured soils.     

提高我国卫生陶瓷产品质量的技术要点

对于原料均化与原料标准化问题,人们还处于已经认识到其重要性,而未按重要问题来对待、来处理的阶段。在许多企业,主要表现在：其一,重视程度不够。选择原料时,当原料质量与原料价格发生冲突时;当进料量与资金发生冲突时;当工艺要求原料堆放方式和堆放场地发生冲突时,都会作出不利于保证原料质量稳定的决定。其二,技术问题。少少企业对于如何根据国内原料的现状,结合工厂的实际进行原料均化,保证原料稳定的技术问题还没有真正解决。     

卫生陶瓷新产品的开发与质量控制

介绍了卫生陶瓷新产品开发的工作程序及开发中的一些经验做法，提出了开发中应注意的一些问题，相信对同行业新产品开发有一定的借鉴和指导作用。     

The use of crossflow to improve nonwoven melt-blown fibers

A stream of unheated crossflow air has been used to make finer melt-blown fibers. Not only are smaller average fiber diameters obtained, but the variation in fiber diameter is smaller. The use of this technique can allow the production of melt-blown nonwovens, which have finer fibers and more uniform webs. Since unheated air is used in the crossflow jet, the fiber enhancement in terms of finer, stronger fibers can be achieved with an energy savings by substituting unheated crossflow air for a portion of the primary air.     

提高克劳斯硫回收装置收率的方法

基于某厂克劳斯硫回收装置,对影响克劳斯硫回收率的因素进行分析,发现反应温度、酸气组成、催化剂、工艺及设备等因素对硫回收率产生重要影响;提出了改进措施来提高克劳斯硫回收装置的回收率,包括:①使用主、副调节阀减小酸性气流量变化的影响;②应用在线分析仪,控制反应计量比;③采用预热空气和酸性气等方法处理含NH3酸性气;④选用性能好的催化剂;⑤调节高温掺合阀开度,控制一级转化器操作温度;⑥采用过程气换热器加热,通过旁路来控制二级转化器操作温度。     

汽车涂装车间产品一次交检合格率提升方法

阐述了强化过程质量控制,提升产品一次交检合格率对汽车生产企业的重要性.以某车间为例,就人、机、料、法、环五个方面影响汽车涂装生产最终产品质量的因素进行了分析,列举了各项问题的解决措施.     

提高PET纺黏非织造布牵伸丝品质的途径

从PET切片品质,熔体品质,纺丝速度和温度,泵供量,采用异形喷丝孔纺丝,控制牵伸丝的稳定性,连续性,提高牵伸气流速度和密度等方面,介绍了提高PET纺黏非织造布牵伸丝品质的途径。     

加强管理 提高水质

新疆中泰化学股份有限公司通过加强水质管理,并采用适宜比例的生化产水和反渗透浓水补入循环水,使腐蚀速率超标的循环水达到了控制指标要求,同时合理利用了生化产水及反渗透浓水,达到了节能减排的目的。     

努力提高过磷酸钙质量

论述以高浓度肥料作为发展方向的今天,过磷酸钙在我国仍应有其一定的地位。介绍扶余化肥厂在以浓酸矿浆法生产过磷酸钙中,采取的一系列技改措施:磷矿配矿使用,增加破碎,提高矿浆细度,定矿调水法磨矿,定浆调酸法混合等,并对磨矿机、混合器、料浆泵、风机等设备进行技改,使产品质量100%达标。     

提高氯乙酸质量的几项措施

着重讨论了以硫磺作催化剂的间歇法生产氯乙酸产品过程中普遍存在质量低的问题,结合本人几年来从事氯乙酸工作的经验,提出了几条提高氯乙酸产品质量的有效措施。     

如何提高电镀产品的质量(一)

通过举例说明4M(即方法、人为、材料和设备)波动差错,阐述了电镀企业建立质量保证体系的必要性.简要介绍了减少波动性差错以及查找故障原因的方法.     

改进工艺 提高隔膜质量

改进吸附工艺，拆除机械搅拌装置，降低吸附真空管，改用先进的动态吸附方法，达到降低槽电压，延长隔膜寿命，减少石棉绒污染的目的。     

浅谈如何提高PVC树脂质量

分析了PVC树脂的质量指标,围绕杂质粒子数、挥发物含量、残留VCM含量等7项质量指标超标问题,提出了一系列措施,该措施实施后提高了PVC树脂的质量。     

提高我厂浮法玻璃退火质量的技术途径

1　前　言我厂 40 0 t/ d浮法玻璃生产线在 2 0 0 2年冷修。针对冷修前存在的退火窑 B、C区短 ,达不到退火要求 ,玻璃板易炸裂等问题 ,进行了大量调查研究及充分论证 ,本着低投入、高质量、高效益的原则 ,决定对退火窑进行技术改造。改造后仅用 2 5天时间就成功地生产出 4～ 1 5 mm7种厚度规格的优质浮法玻璃。检测证明 ,玻璃质量均达本厂的技术标准。汽车级玻璃占产成品的 60 %左右。经过 45天的生产实践表明 ,这次退火窑的冷修技术改造是成功的 ,取得了很好的效果 ,达到了稳产、优质、低能耗 ,提高经济效益的目的。现就我厂退火窑改造的…     

如何提高橡胶半成品的挤出质量

本文从设备,工艺条件和胶料的加工性能等方面,分析了影响挤出半成品的质量问题,进而提出改善挤出半成品质量的方法。