石灰性土壤有效硼浸提剂的评价

Evaluation of Extractants for Available Boron in Calcareous Soil

以采自北京、河北的14个石灰性土壤所进行的微钵栽培番茄所吸收的硼量作为参比标准,研究了曾用于土壤有效硼测定的7种浸提剂的测定值于参比项的相关性。试验结果表明:沸水与沸0.01 mol·L^(-1) CaCl_2溶液浸出硼量基本相同;沸水硼、沸 CaCl_2-B、Morgan-B 和Mehlich 3-B 与番茄植株相对吸硼量的相关系数分别为0.774,0.783,0.764和0.771,均达到极显著水平。说明这4种浸提剂浸出硼量均可作为表征土壤有效硼含量的指数。稀 HCl、NH_4OAc-HOAc 和 DTPA 浸提剂则不适合于石灰性土壤有效硼的浸提。

A micro-pot experiment of tomato seedling culture was conducted on 14 calcareous soils to study the correlation between B uptake of tomato plants and amount of soil available B extracted by each of the seven extractants[hot water,hot 0.01 mol.L^(-1)CaCl_2.Morgan's solution.1 mol.L^1 NH_4OAc-HOAc (pH4.8),dilute HCl.DTPA and Mehlich 3(M3)].The results showed that amount of B extracted by the two extractants(hot water and hot 0.01 mol·L^(-1)CaCl_2)is nearly equal and the correlation between the relative B uptake of plants and amount of B extracted by the extractants(hot water,hot 0.01 mol·L^(-1) CaCl_2.Morgan's and M3)was very significant with r value of 0.774、0.783,0.764 and 0.771. respectively.It indicated that the amount of B extracted by these four extractants can be all taken as satis- fied index for available B in calcareous soil.Morgan's method is more simple、rapid and easier to eliminate contamination than hot water extraction,it would be expected to become routine method in soil laborato- ries and soil test method in field.Although M3 reagent is a good universal extractant,it is not suitable for colormetric quantification of B because its extract is dark in color.The other methods are not suitable for B determination on calcareous soil.