How can water use be conserved in corn cultivation? An analysis of subsurface drip irrigation technology for corn farming.

　　Corn is a common crop in our daily lives; however, its cultivation requires substantial water, often leading to high irrigation costs. So how can corn farming achieve water conservation? Subsurface drip irrigation represents a significant breakthrough in modern water‑saving irrigation. By integrating the advantages of various water‑efficient irrigation techniques, it establishes an independent irrigation system that uses minimal water to effectively irrigate large areas of farmland, thereby achieving objectives such as water savings, moisture retention, temperature regulation, improved soil properties and light conditions, accelerated crop growth and development, and increased grain yields. Next, we will discuss its application in corn cultivation, enabling more effective water‑conservation goals throughout the growing and management process.

　　 1. Site and Crop Rotation Selection

　　Select fields with a deep plow layer, high soil fertility, good water and nutrient retention, and effective drainage.

　　 2. Perform meticulous land preparation, leveling, and fine harrowing.

　　To ensure effective incorporation of crop residues into the soil, thorough mechanical chopping and, when necessary, manual removal of remaining stubble are essential. During autumn tillage, deep loosening should be carried out to achieve a compacted top layer and a loose subsoil free of clods and soil lumps. Simultaneously with tillage, apply sufficient base fertilizer and promptly perform compaction to bring the field to an optimal condition for sowing, thereby creating a favorable soil environment for high‑quality mulching.

　　 3. Apply balanced fertilization and increase the application of organic fertilizers.

　　Typically, 1,000–2,000 kg of high-quality organic fertilizer, 15–20 kg of diammonium phosphate, and 5–10 kg of potassium sulfate are applied as base fertilizer per mu; alternatively, 30–40 kg of compound fertilizer may be used as the base application. During the critical nutrient‑demand period for corn, liquid topdressing is applied via a drip‑irrigation system along with irrigation water. On the basis of adequate base fertilization, an additional 20–25 kg of urea per mu is generally applied.

　　 4. Form high ridges and plant two rows per ridge.

　　In plastic-mulched corn cultivation, a wide–narrow row planting pattern is employed to enhance field ventilation and light penetration, thereby fully leveraging the edge effect. Typically, the narrow rows are 40–50 cm wide, while the wide rows measure 80–90 cm. Densely planted, stress‑tolerant varieties can be selected, with plant densities increased by 500–800 plants per mu compared to conventional practices, thus boosting yields through population density. Suitable local tillage and ridge‑forming methods include:

　　(1) Two‑ridge‑one‑platform system: After applying fertilizer through furrow application, alternate ridges are raised, creating three fertilizer bands within each ridge. The ridge spacing is 130 cm, with two rows of corn planted on the ridge, a narrow row spacing of 40 cm, and a wide inter‑row spacing of 90 cm. Fields that have not yet been ridged are plowed flat. Following the standard ridge width of 130 cm, deep furrows are dug to form the main ridges, then leveled with a harrow and promptly compacted. During planting, double furrows are opened on the ridge platform for fertilizer placement, with a furrow spacing of 40 cm, and base fertilizer is evenly distributed into the furrows.

　　(2) Wide–narrow row planting pattern: In this pattern, ridges are 65 cm wide. During land preparation, fertilizer is applied at a deep placement. Sowing precedes mulching. Two rows are grouped together, with the inter‑row spacing set at 50 cm, while the distance between adjacent groups is 80 cm.

　　 5. Variety Selection

　　Select varieties with a growing period 7 to 10 days longer than that of open-field cultivars and an accumulated effective temperature of 150 to 200°C more. Typically, choose varieties with a growing period of 115 to 180 days, an accumulated effective temperature of 2,450 to 2,500°C, a compact plant architecture, and suitability for dense planting.

　　 6. Sowing with adequate soil moisture

　　Under‑mulch drip irrigation for corn employs a no‑till planting method, with seeding followed by mulch application. After emergence, seedlings should be promptly thinned by hand, and the base of each plant firmly pressed with soil. Mulching raises soil temperature, allowing planting to begin up to five days earlier; typically, sowing occurs in late April. On raised beds, mechanical furrow‑opening is used, followed by flood irrigation and precision spot‑sowing, with narrow row spacing of 40–50 cm. Seed depth must be uniform, and soil coverage even, at approximately 3 cm. Planting density is determined according to the variety’s specific characteristics, generally maintaining 4,500–5,000 plants per mu.

　　 7. Laying drip irrigation tubing and applying mulch film

　　Lay drip irrigation tubing between the two narrow rows of corn on the wide ridge, and apply mulch film simultaneously. Use a 130‑cm‑wide plastic mulch; mulching can be done manually or with machinery, and must be tight, secure, and well‑pressed.

　　 8. Ventilate promptly, guide seedlings, and thin out seedlings.

　　After sowing, promptly check for emergence and, if gaps appear, promptly re-sow or transplant seedlings. Once corn has emerged, thin the stands in a timely manner, removing seedlings that are discolored, uneven in size, or affected by pests or diseases, and retain only the healthiest, most vigorous plants to prevent damping-off, scorching, or heat injury. Following thinning, firmly press moist soil over the thinned-out areas to seal the planting holes, and promptly secure both edges of the plastic mulch to prevent it from being lifted by the wind.

　　 9. Strengthen field management

　　In corn mulch cultivation, regularly inspect the plastic mulch to ensure it is tightly sealed; if any tears or areas are not adequately covered with soil, promptly press them down with soil to prevent wind from lifting the film, thereby maintaining soil moisture and temperature. Promptly remove weeds from the furrows, and irrigate by drip according to the crop’s water‑requirement schedule.

　　 10. Remove the plastic mulch

　　Manual membrane cleaning may be employed, or mechanical membrane cleaning may also be used.