Universal extraction agent for soil and soil nutrient extraction method

Abstract

The invention relates to a universal extraction agent for soil and a soil nutrient extraction method. The universal extraction agent for soil is a NaHCO3 aqueous solution with the concentration of 0.6-0.7 mol/L. The extraction method comprises the following steps: weighing a certain amount of an air-dried soil sample, or weighing a fresh soil sample with the same dry weight, putting in a container, adding phosphorus-free active carbon accounting for 20-30 wt% of the soil sample, then adding the soil universal extraction agent according to the solid-liquid ratio of 1 g:18-25 mL, oscillating under the conditions that the temperature is 20-25 DEG C and the rotation speed is 150-200 r/min, and filtering, so as to obtain the filtrate, wherein the filtrate is a to-be detected liquid. The universal extraction agent is a single reagent, the preparation process of the extraction agent is simple, extraction is sufficient, cost is low, and the universal extraction agent is applicable to neutral and calcareous soil, is capable of extracting soil ammonium nitrogen, rapidly-available phosphorus and rapidly-available potassium, and also is capable of extracting soil nitrate nitrogen.

Description

technical field [0001] The invention belongs to the field of agricultural testing, and in particular relates to a general soil extraction agent suitable for neutral and calcareous soils and a soil nutrient extraction method. Background technique [0002] The abundance of soil nutrients not only directly affects the growth and production of seedlings, but also measures the effect of fertilization and determines whether it is necessary to fertilize, which is the basis for fertilization. When formulating a fertilization plan, soil nutrition diagnosis should be carried out first, and the type and quantity of fertilizer should be determined according to the soil nutrient content and supply status. There are two kinds of methods commonly used in soil nutrient diagnosis: soil nutrient routine determination method and soil nutrient rapid measurement method. The conventional soil nutrient determination method has high accuracy and has certain guiding significance in field fertilizat...

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Problems solved by technology

[0004] Chinese patent document CN101251450A discloses a combined extraction agent (0.40~0.50mol/LNaHCO 3 , 0.020~0.030mol/LNa 2 CO 3 , 0.30~0.40mol/LNa 2 SO 4 , pH value is 8.4 ~ 8.6), can quickly extract ammonium nitrogen, nitrate nitrogen, available phosphorus, and available potassium in one dip, but its composition is complex, the required reagents are more, and the cost is higher. Repeated steps are required in the preparation process Adjusting the pH value is time-consuming and labor-intensive

[0005] Therefore, the above existing soil extraction agents still have the following problems: (1) What have is that ava