Detailed Explanation of Key Techniques for High-Yield Spring Corn Cultivation
?I. Apply Sufficient Base Fertilizer and Prepare the Land Carefully
When preparing the land, apply 2000 kg of organic fertilizer per mu, with 30% of the total nitrogen fertilizer and all phosphorus and potassium fertilizers used as base fertilizer. Land preparation must meet the six-character standard of "deep, loose, broken, level, clean, and moist." This lays a solid foundation for achieving a full stand in one sowing.
????II. Select Varieties
Currently, the varieties suitable for spring corn production in our city mainly include: for grain use, Jinhai No. 5, Nongda 108, Danyu 86, Weiyu 308, Qingnong 105, etc. For processing and fresh consumption, there are Xixing Black Glutinous No. 1, Xixing White Glutinous No. 2, Yannuo No. 6, Yannuo No. 7, White Horse Prince, etc.
????III. Seed Treatment
Coating with 5.4% pyraclostrobin-pymetrozine corn seed coating agent can control small brown planthoppers, aphids, and maize rough dwarf disease at the seedling stage; seed dressing with fungicides such as tebuconazole, thiram, and tricyclazole can reduce the occurrence of maize head smut; seed dressing with phoxim can control underground pests such as cutworms and wireworms.
?IV. Sow Early at the Right Time and Improve Sowing Quality
1. Sow early at the right time by making use of available soil moisture: In combination with current climatic conditions, once conditions are suitable, strive to sow early by making use of available soil moisture. In order to avoid the peak damage period of the first generation of small brown planthoppers, strive to finish sowing before the end of April.
2. Appropriate sowing rate: The sowing rate is generally 2-2.5 kg per mu, adjusted as appropriate according to variety characteristics.
3. Sowing specifications: Corn sowing should be uniform in depth, with a sowing depth of 3-5 cm; row spacing of 60-70 cm.
?V. Balanced Fertilization
Determine the amount of fertilizer based on yield targets and soil fertility levels. Generally, calculate the fertilizer requirement based on applying 3 kg of nitrogen (N), 1 kg of phosphorus (P2O5), and 2 kg of potassium (k2O) for every 100 kg of grain produced. For plots deficient in zinc, add 1 kg of zinc sulfate per mu. Topdressing can be carried out in two applications, namely heavy application of ear fertilizer and supplementary application of flower-grain fertilizer.
?VI. Reasonable Close Planting
Implement reasonable close planting according to variety characteristics and yield targets. For example, the seedling density of Danyu 86 is generally controlled at 3500-4000 plants per mu, Qingnong 105 at 3500-3700 plants per mu, Weiyu 308 at 4000-4500 plants per mu, and Jinhai No. 5 at 4200-4500 plants per mu. For plots with better soil fertility, take the upper limit; otherwise, take the lower limit.
????VII. Strengthen Integrated Control of Diseases, Insects, and Weeds
Following the principle of "prevention first, integrated control," implement a combination of agricultural control, biological control, physical control, and chemical control. The use of pesticides should meet pollution-free requirements.
1. Weed control: Choose pre-emergence or post-emergence corn herbicides for chemical weeding. After sowing, when soil moisture is good, spray 40% acetochlor-atrazine mixture at 200-250 ml per mu, or 33% pendimethalin emulsifiable concentrate at 100 ml plus 72% metolachlor emulsifiable concentrate at 75 ml plus 50 liters of water for sealed spraying; when soil moisture is poor, spray 4% nicosulfuron suspension concentrate at 100 ml per mu at the 3-5 leaf stage of corn seedlings and the 2-5 leaf stage of weeds.
2. Diseases: In recent years, maize rough dwarf disease has occurred on a large scale in our city, seriously affecting spring corn yield. We should attach great importance to this and take the following measures for prevention.
① Select disease-tolerant varieties
Currently, there is a lack of highly disease-resistant improved varieties in corn production, but there are still certain differences in susceptibility among varieties. For example, Nongda 108, Jinhai No. 5, etc., are relatively resistant to maize rough dwarf disease.
② Adjust sowing date
Choose a safe sowing period to avoid the leaf age stage when corn is susceptible to disease. Spring corn sowing must ensure that before the mass migration and spread of small brown planthoppers in late May, the visible leaf age reaches more than 7 leaves, so that the corn seedling stage avoids the peak occurrence period of small brown planthoppers.
③ Clear weeds
Timely clear weeds in and around corn fields, control the source of the virus, eliminate the overwintering and breeding sites of the virus-transmitting vector small brown planthopper, and reduce opportunities for virus transmission.
④ Strengthen field management
Appropriately increase the sowing rate and delay final thinning; generally, final thinning is done after 6-7 leaves. Once some plants are infected, combine with final thinning to pull out diseased plants in the field and dispose of them centrally. Fertilize reasonably, increase the application of organic fertilizer and phosphorus-potassium fertilizer, promote vigorous growth of corn, and enhance disease resistance.