China's lack of molybdenum soil distribution and soil boron deficiency is very consistent with the lack of molybdenum in soils are these two major areas of the Yellow River in northern loess and alluvial soil parent material is mainly due to low molybdenum containing, acidic soil and south to Mo mainly due to soil acidity reduces the effectiveness of molybdenum. Extract effective boron present only a hot water extraction, soil liquid ratio 20:40, with curcumin method or azomethine -H colorimetric assay method. Effective application of soil extraction of molybdenum is more common pH3.3 oxalate - ammonium oxalate reagent (Tamm solution). Such agents can be eluted simultaneously an equivalent amount of iron and aluminum, so that it can extract some more than the effective amount of molybdenum, when the soil to effectively test value molybdenum interpreted to take into account the soil pH is necessary. Oxalic acid - ammonium oxalate extraction of molybdenum available molybdenum thiocyanate colorimetric assay can also be used by Catalytic Polarography, 1972 Dawson put forward effective determination of molybdenum in soil anion exchange resin, the resin extracted for 46 kinds of soil and plant uptake of molybdenum between molybdenum, r = 0.861, for an effective low molybdenum content of the soil, this approach may be the best extraction method for the determination of soil available molybdenum. In addition, the concept of molybdenum values ??is also useful, molybdenum value = pH + (effective molybdenum × 10), its indicators: limit <6.2, a modest 6.2 to 8.2, the upper limit of> 8.2. 7, extraction agent selected studies described above soil available nutrients various extraction agent, and generally applicable, each region should screening for local extraction agent according to local soil conditions. Extraction agent screening method was used in the extraction of several different soil bioassay agents, soil available nutrient leaching agent made each extract content and biological reference standard to compare and calculate the correlation coefficient. The usual practice is to select a lot of 20 soil samples within the test area, the soil sample should be representative of soil fertility in the region, both low-yielding land, but also soil samples yielding plots. In the test venue arrangements pot experiment, because this test is available crop seedlings, so it can be a smaller pot, both low-yielding land, if you want to get the production is the result of the application of the bigger pots. The experiment included a full fat group (NPK), nitrogen-free group (P and K), phosphorus group (nitrogen and potassium) and non-potassium group (N and P) 4 treatment, repeat 3-4 times. Can be used for the test crop main local crops and cultivars. 20 kinds of soil in front of Zhuangpen fertilization, first base depicting a soil sample, potted seedlings grow to a certain height (usually 40 to 60 days), the charge shoots, measuring fresh weight, dry spare. If soil phosphorus extraction agent selection, the choice of three kinds of extraction agent for about 20 kinds of soil samples for determination of phosphorus content basis, while the full-fat group pot experiment, two groups of non-phosphorus plant samples for testing its phosphorus content, and the dry weight was measured to phosphorus group plant dry weight / dry weight of whole plant fertilizer group × 100 for relative yield (%). 20 soil samples of soil available basis plant and pot experiment measuring the dry weight of the plant or the relative yield value of grain yield, plant P uptake and other statistical correlation between them. Select the relevant value high soil phosphorus extraction method is used as the standard measure of soil phosphorus in the region.陆允甫 et al (1987) for the screening of Red Soil phosphorus determination of arable land were studied. Zhejiang Jinhua, Quzhou County cities were a total of seven large-scale field trials of fertilizer, two years a total of 40 points. Tested soils are acidic, pH (H 2 O1: 1) 4.9 ~ 6.85 (excluding two pH greater than 7), organic matter content of 0.68% ~ 2.72%, 0.04% total nitrogen, 0.156%, 0.014% total phosphorus 0.045%, clay content (<0.002 mm) 15.31% - 53.27%. Red earth soil is classified as sub-category below several representative soil genus. Test set NPK treatment and processing nitrogen and potassium, and zinc sulfate administration; four replications. Instructions for the corn crop (Danyu VI). Access test: ① relative yield of corn grain er; ② total dry matter yield relative; ③ whole plant total P uptake; ④ grain phosphorus and other four as reference standards. The correlation coefficient method different methods available phosphorus determination (logP) and reference items relative yield of corn grain (n = 35) relative to the total dry matter yield (n = 35) whole plant P uptake (n = 29) containing corn kernels phosphorus content (n = 31) of the common soil test points with 10 kinds of production methods to extract Determination of available phosphorus. Determination of the correlation coefficient for each extraction results and four reference criteria. The correlation coefficient between the measurement results of each method to extract each other's Table