Use of Sewage Sludge After Liming as Fertilizer for Maize Growth

农业土地上的污水污泥的使用为它的处理提供一种选择。因此，现在的学习的目的是评估使用在巴基斯坦生产的工业污水污泥的可行性，作为农业化肥。与 250 g kg 修改的农业土壤 ? 1 污水污泥与或没有石灰处理被用于普通本地谷类罪的生长，玉米(Zea 玉米) 。在污泥样品的踪迹和有毒的金属的活动性被使用一个修改 BCR 顺序的抽取过程估计。单个抽取过程由温和提炼之物(CaCl2 ) 和水的申请组成，为容易可溶的金属部分的比例的评价。为了在顺序的抽取过程的每步检查分析结果，踪迹的集中和有毒的金属的精确，被总结并且与全部的金属集中相比。植物可得到的金属满足，由 deionized 水和 0.01 摩尔 L 显示了? 1 CaCl2 答案抽取部分和顺序的抽取的可交换的部分，显著地减少了( P < 0.05 )用石灰申请因为在更高的 pH 的减少的金属可获得性，除了在 Cd 和 Cu 的情况中，其活动性是，稍微增加了。污泥改正提高了玉米的干燥重量收益，增加为有石灰处理的土壤是更明显的。施用石灰污水污泥在谷物纸巾减少了踪迹和有毒的金属内容除了 Cu 和 Cd，它在这些金属的可允许的限制下面。现在的实验证明施用石灰是在在修改污泥的土壤便于玉米的生长的一个重要因素。

The use of sewage sludge on agricultural land provides an alternative for its disposal. Therefore, the aim of the present study was to evaluate the feasibility of using industrial sewage sludge produced in Pakistan, as an agricultural fertilizer. The agricultural soil amended with 250 g kg^-1 sewage sludge with or without lime treatment was used for the growth of the common local grain crop, maize （Zea maize）. The mobility of the trace and toxic metals in the sludge samples was assessed by applying a modified BCR sequential extraction procedure. The single extraction procedure was comprised of the application of a mild extractant （CaCl2） and water, for the estimation of the proportion of easily soluble metal fractions. To check the precision of the analytical results, the concentrations of trace and toxic metals in every step of the sequential extraction procedure were summed up and compared with total metal concentrations. The plant-available metal contents, as indicated by the deionized water and 0.01 mol L^-1 CaCl2 solution extraction fractions and the exchangeable fraction of the sequential extraction, decreased significantly （P 〈 0.05） with lime application because of the reduced metal availability at a higher pH, except in the cases of Cd and Cu, whose mobility was slightly increased. Sludge amendment enhanced the dry weight yield of maize and the increase was more obvious for the soil with lime treatment. Liming the sewage sludge reduced the trace and toxic metal contents in the grain tissues, except Cu and Cd, which were below the permissible limits of these metals. The present experiment demonstrates that liming was an important factor in facilitating the growth of maize in sludge-amended soil.