酸性根际肥对石灰性土壤pH和铁有效性的影响研究

Effect of acidic rhizosphere fertilizer on the soil pH and Fe availability of calcareous soil

在无植物栽培的条件下通过肥料在土壤中的扩散试验研究酸性根际肥对石灰性土壤 pH值、有效铁含量的影响 ,利用盆栽试验验证对石灰性土壤上花生缺铁失绿黄化症的矫正效果。结果表明 ,酸性根际肥 (pH 1.0～ 2 .0 )中的酸在土壤中扩散的影响半径可达 6cm ,但对土壤pH降低作用最显著的是在距肥料 2cm内 ;在施肥 2 8d内 ,距肥料 2cm处 ,土壤 pH值降低了 0 .9个单位 ,土壤铁有效性 (DTPA浸提量 )增加了 5 .9mg kg ;施用酸性根际肥可使花生叶绿素SPAD值与叶片活性铁含量显著提高 ,克服了花生缺铁黄化症状 ,使施肥区 (肥料周围 2cm内 )土壤pH值显著降低 ,并显著提高了该区土壤铁的有效性和花生对土壤Fe的吸收量。

A diffusion experiment and pot trial were conducted to evaluate the effect of acidic rhizosphere fertilizer on the soil pH and Fe availability and the growth, iron deficiency correction of peanut on calcareous soil. The results indicate that application of acidic fertilizer with pH 1-2 decreased the soil pH within 6cm from application point due to the diffusing of H+ from the acidic fertilizer in incubation period of 4 weeks. The extent of pH changes reached 0.9 unit and soil DTPA extractable iron concentration increased by 5.9 mg/kg with 2cm diameter of fertilizer. Results also indicated that acidic fertilizer application increased in the chlorophyll SPAD value, active Fe concentration in peanuts leaves and the total amount of Fe uptake. Therefore, the acidic rhizosphere fertilizer was efficient in correcting iron chlorosis on the calcareous soil in this experiment.