The flowering stage of corn is the period from tasseling to maturity. During this time, vegetative growth has largely concluded, and the focus shifts to reproductive growth, centered on pollination and fertilization. This phase is critical for yield formation, as it determines the number of kernels and their weight. The primary goal of management during this stage is to strengthen roots, protect leaves, prevent premature aging, extend the functional period of green leaves, avoid grain abortion, and increase both the seed setting rate and grain weight.
Key field management practices include:
1. **Applying Fertilizer Appropriately**: High-yield farming has shown that a large leaf area, high photosynthetic efficiency, and long leaf function periods are essential for high yields. Sufficient inorganic nutrients during the flowering stage are crucial for stalk ripening. Farmers should apply fertilizer based on plant appearance—those with good growth may not need additional fertilizer, while weaker plants should receive granular fertilizer. Typically, 5 kg of urea or 10–15 kg of ammonium bicarbonate is applied before or after tasseling, combined with watering. Foliar sprays such as 1–2% urea solution, 3–5% leach solution, or 0.1–0.2% potassium dihydrogen phosphate can also be used to enhance leaf function and kernel weight by over 7%.
2. **Removing Tassels Timely**: Removing male flowers (emasculating) reduces nutrient consumption, improves light penetration, and enhances lodging resistance. It also helps control pests like corn borers and aphids. Emasculation should be done before tassels open, avoiding early leaf removal. Typically, no more than half the plants should be emasculated, and care must be taken to avoid conditions that might lead to pollen deficiency, which could result in barren ears.
3. **Assisted Pollination**: Artificial pollination ensures proper fertilization, increases seed setting rates, and promotes uniform grain development. It is especially effective for late silking plants. Pollination is usually carried out between 9 and 11 am on sunny days, with 2–3 rounds of pollination. Different plants should be pollinated to maximize effectiveness.
4. **Timely Irrigation and Drainage**: The flowering and grain-filling stages are critical for water demand, accounting for about 50% of total water use. Soil moisture should be maintained at 70–80% of field capacity. Two key irrigation times are: one during flowering to seed formation, and another during the milk stage to increase grain weight. Sandy soils require more frequent irrigation, while clay soils should be filled when needed. Excessive rain requires timely drainage.
5. **Removing Weak Plants**: Some plants may develop into empty stalks or small, low ears. These should be removed after pollination to concentrate nutrients and water on healthy plants, resulting in larger, more productive ears.
6. **Shallow Cultivation and Weeding**: In the late grain-filling stage, shallow cultivation breaks up soil compaction, promotes root absorption, and controls weeds. Care must be taken to avoid excessive root damage or blade breakage.
7. **Pest and Disease Control**: Common pests and diseases during this stage include corn borers, armyworms, aphids, leaf spot, and rust. Pesticides like DDVP, phoxim, and carbendazim are commonly used. Spraying solutions at appropriate concentrations helps manage these issues effectively.
8. **Harvesting at the Right Time**: Corn is ready for harvest when the leaves turn yellow, grains harden, and a black layer forms at the base of the kernels. Delaying harvest by 5–7 days, if conditions allow, can further increase yield.
Author: Chen Maochun
Source: Farmers Daily
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