Department of Soil Science, Faculty of Agriculture, Shahed University, Tehran, Iran.
J Trace Elem Med Biol. 2018 May;47:149-155. doi: 10.1016/j.jtemb.2018.02.007. Epub 2018 Feb 6.
The solubility of iron (Fe), as an important micronutrient for plant growth, is not high in the calcareous soils, and hence efficient methods must be used to increase its availability for plant use. Accordingly, a two-year research work was conducted to investigate the effects of composted municipal solid wastes (MSW) on Fe accumulation and fractionation in a calcareous soil. Treatments including MSW levels at (0 (control), 15 (MSW1), 30 (MSW2) and 60 (MSW3) t ha dry weight) and usage time (yearly (T1) or biyearly usage (T2)) were tested in a factorial experiment on the basis of a completely randomized block design with three replications. The compost was salty and contained the total Fe of 16200 mg kg. The concentrations of plant available Fe fractions including the exchangeable (EX), carbonates-bound (CA), organically-bound (OM), and Fe-Mn-oxide-bound (FM) as well as the residual (RE), DTPA- and Total-Fe fraction were determined. MSW increased levels significantly enhanced Fe concentration in different soil fractions as the least and the highest Fe concentrations were resulted by the control and the MSW3 treatments, respectively. The effects of T treatment were also significant on different Fe fractions excluding CA fraction. The Fe fractionation using the Tessier consecutive extraction method indicated the following order of Fe distribution and concentration in different soil fractions: RE > FM > OM > CA > EX. Iron was mostly found in the following fractions RE (>90%), FM (>6%) and OM (>2%). Different soil properties including EC (positively), pH (negatively), CEC (positively) and organic matter (positively) were highly and significantly correlated with different Fe fractions indicating how the use of MSW can affect the properties of calcareous soils. It is possible to increase Fe availability in different soil fractions using composted municipal solid wastes, which is of agronomical, health and environmental significance.
铁（Fe）作为植物生长的重要微量营养素，在石灰性土壤中的溶解度不高，因此必须采用有效的方法来提高其对植物的可用性。因此，进行了为期两年的研究工作，以研究堆肥城市固体废物（MSW）对石灰性土壤中铁积累和形态的影响。该研究采用完全随机区组设计，设置了包括 MSW 水平（0（对照）、15（MSW1）、30（MSW2）和 60（MSW3）t/ha 干重）和使用时间（每年（T1）或每两年使用一次（T2））在内的处理，共 3 个重复。堆肥盐分含量高，总铁含量为 16200mg/kg。测定了植物有效铁形态，包括可交换态（EX）、碳酸盐结合态（CA）、有机结合态（OM）、铁锰氧化物结合态（FM）和残渣态（RE）、DTPA 提取态和全铁态。MSW 水平的增加显著提高了不同土壤形态中铁的浓度，其中最低和最高的铁浓度分别由对照和 MSW3 处理产生。T 处理对不同铁形态的影响也非常显著，除了 CA 形态外。Tessier 连续提取法的铁形态分析表明，不同土壤形态中铁的分布和浓度顺序为：RE>FM>OM>CA>EX。铁主要分布在以下形态中：RE（>90%）、FM（>6%）和 OM（>2%）。不同土壤性质，包括电导率（正相关）、pH（负相关）、阳离子交换量（正相关）和有机质（正相关）与不同铁形态高度显著相关，表明了 MSW 的使用如何影响石灰性土壤的性质。使用堆肥城市固体废物可以提高不同土壤形态中 Fe 的有效性，这在农业、健康和环境方面具有重要意义。
