First, the classification of molybdenum-deficient soil The effective molybdenum content of the upper soil: less than 0.10 mg / kg is very low, 0.10 ~ 0.15 mg / kg is low, 0.16 ~ 0.20 mg / kg is medium, more than 0.21 mg / kg is rich. The soil effective molybdenum content of 0.15 mg / kg is the soil critical value of wheat molybdenum deficiency.
Second, the lack of molybdenum wheat symptoms of wheat deficiency of molybdenum (particularly nitrogen fertilizer and low temperature), wheat seedlings began to develop in the four-leaf stage, initially in the upper leaves of the old leaves along the veins to produce white spots, then gradually become linear, flaky, Until dry; but the lower part of the leaf is better. The leaves were chlorotic only in the case of severe deficiency of molybdenum, the leaf tips and leaf margins were gray, the flowering ripening was delayed, the kernels shrunk, and the glume growth was abnormal.
Third, the physiological role of molybdenum fertilizer
(1) Application of molybdenum fertilizer can promote nitrogen metabolism in wheat. The main physiological function of molybdenum in crops is to affect the process of nitrogen metabolism. After the nitrates are absorbed by the crops, they must be converted to ammonium nitrogen under the action of nitrate reductase to participate in the synthesis of plant proteins. Molybdenum is a nitrate reductase. An indispensable component. Therefore, the nitrate in the leaves of the molybdenum-deficient wheat plants will accumulate in large amounts, which makes it difficult to synthesize proteins. It was determined that the nitrogen content in wheat plants was increased by 4.10% and 1.21%, respectively. The nitrogen content in wheat plants increased by 4.10% and 1.21%, respectively. At the same time, the protein content of wheat plants increased, and the amino acid content (except proline) also increased significantly.
(2) Application of molybdenum fertilizer can promote the metabolism of phosphorus in wheat. Molybdate affects the chemical hydrolysis of orthophosphorus salts and pyrophosphate salts, and also affects the proportion of organic phosphorus and inorganic phosphorus in crops. It was determined that the inorganic phosphorus in the leaves of molybdenum-deficient wheat was 4-6 times higher than that in normal leaves. After re-supplying molybdenum for 2 to 4 days, the content of organic phosphorus in the leaves of the original molybdenum-deficient wheat began to recover. About 20 days, the content of organic phosphorus in wheat plants was higher than that in the control. Increase by 15.20%.
(3) Molybdenum application can improve the cold resistance of wheat. Under low temperature stress, photochemical reaction and photosynthetic capacity increased, nitrogen metabolism and phosphorus metabolism increased, and soluble sugar in wheat leaves increased, which increased the ability of wheat to resist cold damage in early spring. According to field investigations, molybdenum reduced the mortality rate of wheat freeze damage by 10% to 18%.
(4) Molybdenum application can increase the chlorophyll content of wheat. The application of molybdenum in wheat can significantly increase the chlorophyll content of leaves in various periods, especially the chlorophyll content of flag leaves. Therefore, the leaf senescence is delayed, the leaf function period is prolonged, the photosynthesis intensity and photosynthetic capacity and time of wheat are increased, the 1000-grain weight is increased, and the yield of wheat is increased.
(5) Molybdenum application is conducive to the accumulation and operation of dry matter in wheat. With the increase of photosynthetic area of ​​wheat plants after molybdenum application, the accumulation and operation of dry matter was promoted. It was determined that the dry weight of wheat per plant after molybdenum application increased by 10.21% compared with the control (measured at maturity), and the economic coefficient increased from 0.3761 to 0.4177.
Fourth, the effect of moxibustion yield increase
According to the molybdenum test: in the soil with low effective molybdenum content, the ammonium molybdate solution with 0.05~0.10% concentration was used for wheat soaking, 502.7 kg of wheat per mu, 16.47% increase compared with the control 431.6 kg, and the average kernel number increased by 1.20. The 1000-grain weight is increased by 1.01 g; in the soil with a low effective molybdenum content, molybdenum is used at a concentration of 0.05 to 0.10%.
Source: Rural Practical Technology and Information
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