What type of fertilizer should be applied to top dressings should be “looking at the sky and looking at the looksâ€. According to specific conditions, “seeing the sky†should be based on the weather conditions. It should be done when there is no wind on a sunny day. The effect is not good, spray fertilizer can also be combined with the prevention and control of late diseases and pests: "see the ground, look at the long phase" is based on soil nutrient status, wheat growth and appearance to determine the type and amount of fertilizer.
From the heading stage to the milk ripening stage, if the leaves are yellow in color and the premature aging wheat fields are defertilized, the focus should be on nitrogen fertilizers. Each acre with 50 ~ 60 kg 1% ~ 2% urea or 2% ~ 4% ammonium sulfate solution spray, the effect of increasing production is very significant, generally spray 1 to 2 times can increase production of 5% to 10% of wheat, high yield can increase 20 %about.
In high-yielding wheat fields with no premature aging, nitrogen fertilizers are generally not topdressed; late-maturing wheat matures may be used, and no nitrogen fertilizer may be topdressed. In these two types of wheat fields, the concentration of 0.2% to 0.4% of potassium dihydrogen phosphate solution or 5% of turfgrass gray water should be sprayed with a concentration of 50 to 60 kilograms per mu, which can achieve a certain increase in yield. According to the test, the grain weight can generally be increased by 1 to 3 grams, with an increase of 5% or more, and a high yield of about 15%.
For phosphorus-deficient wheat fields with more nitrogenous fertilizers, spraying of 2% to 4% of superphosphate solution, or 0.2% to 0.3% of potassium dihydrogen phosphate solution per acre of 50 to 60 kg, can also be used to promote grain filling. Increase the effect of 1000-grain weight. The middle and low yield wheat fields can be sprayed with nitrogen and phosphorus, which has a very obvious effect on promoting grain filling and delaying plant senescence.
To listen carefully to the weather forecast, when there is dry hot wind, no matter what kind of wheat fields, promptly sprayed potassium hydrogen phosphate or gray water, etc., have the role of defense against dry hot wind.