What are the technical measures for managing summer corn during the flowering and grain-filling stage?

The main goal at this stage is to maintain roots and protect leaves, prevent premature senescence and excessive vegetative growth, extend the functional period of green leaves, prevent grain abortion, and improve seed-setting rate and grain weight.

First, apply grain fertilizer skillfully: so-called skillful application should be determined by the appearance of plants in the field. In fields where ear fertilizer is sufficient, plants look good, leaf color is dark green, and there is no sign of premature senescence and fading, it may be unnecessary to apply fertilizer, so as to avoid prolonging the growth period. If ear fertilizer is insufficient and plants show signs of nutrient deficiency, grain fertilizer should be applied as a supplement. The principle for applying grain fertilizer is “better early than late.” Generally, apply 5 kg of urea per mu or 10-15 kg of ammonium bicarbonate, and place it deep in holes. A mixed solution of 1%-2% urea and 0.4%-0.5% potassium dihydrogen phosphate can also be used for foliar spraying, using 70-100 kg of solution per mu.

Second, irrigation and drainage: soil moisture should be maintained at 70%-80% of the field maximum water-holding capacity, which is favorable for flowering and fertilization. If there is drought, irrigate in time; if the field water-holding capacity exceeds 80%, pay attention to drainage.

Third, detasseling every other row: when corn has just tasseled, remove tassels every other row or every other plant, removing one-half of the tassels in the whole field, which helps field ventilation and light penetration, saves nutrients, reduces insect damage, and can increase yield by 5%-8%. The detasseling method is: when the tassel has emerged 1/3 or 1/2 from the top leaf, before pollen shedding, promptly pull out the tassel every other row or every other plant. It is best to remove the tassels of plants that tassel first or weak plants and insect-damaged plants, but do not detassel the few rows at the field edge, so as not to affect pollination. When detasseling, never damage the top leaves, and even more, do not cut off the stems and leaves above the ear, otherwise yield will be reduced.