What are the growing environment requirements for the sword bean?
The sword bean is a climbing herbaceous vegetable of the legume family, and generally its tender pods and seeds are eaten. It is distributed in the region south of the Yangtze River and is grown in subtropical and tropical areas. It can also be used as green manure and livestock feed. Growing sword beans has relatively strict environmental requirements and certain limitations; in general, it has its own requirements for climate, temperature, moisture, fertilizer nutrients, light, and soil, and only in suitable environments can it grow well.
1. Climate
Only under tropical and subtropical climate conditions can it complete its growth process, flower and set pods, and grow normally. In cold regions it does not sprout, and even if it sprouts, its growth and development are incomplete, or flowers and pods drop. When growing it in subtropical regions, attention must also be paid to the effects of a late spring cold spell, and sowing should be appropriately delayed.
2. Temperature and humidity
It likes warmth and tolerates heat. Seeds germinate above 18 degrees, and the most suitable temperature for germination and leaf growth is between 18 and 28 degrees. The best temperature during flowering is between 25 and 30 degrees, and the temperature during pod setting should not be lower than 20 degrees or exceed 35 degrees. Before the seedlings emerge and during the seedling stage, soil moisture should be kept at about 70%; during flowering, humidity should be reduced to 40%; and during the fruiting stage, keeping it at 50% is fine.
3. Fertilizer and nutrients
Do not water before flowering; carry out one intertillage to avoid flower drop. Apply one topdressing during the period of vigorous leaf growth, applying 60 jin of compound fertilizer per mu, mainly nitrogen fertilizer. After pod setting, apply topdressing again, applying 30 jin of superphosphate and 20 jin of potassium dihydrogen phosphate per mu, with less nitrogen fertilizer. During the peak pod-setting period, spray fertilizer 2 times, and at the same time pinch the growing tips and thin the branches to concentrate nutrients for pod setting. A topdressing of compound fertilizer can be sprayed once in the later stage to prolong the pod-setting period.
4. Light
The sword bean likes strong light and needs to receive long periods of sunlight. Especially during flowering and pod setting, it needs a large amount of light; insufficient light will cause flowers and pods to drop. Generally, suitable climates and suitable seasons can meet this, but planting must not be too dense. Appropriate plant and row spacing should be maintained so that it can fully receive light and improve light use efficiency.
5. Soil
The planting soil must have good water and fertilizer retention. Because growing temperatures are high and light is strong, transpiration is rapid, so water retention is very important. It likes fertility while growing, so fertile soil is best. It must not be compacted, as compaction restricts root growth and the absorption of water and nutrients. After rain, roots are prone to rotting. It must not be saline-alkali land, where seeds and seedlings easily die. It must not be low-lying land, where respiration and growth easily become abnormal.
When growing sword beans, environmental requirements should be adjusted and improved according to their needs to achieve the best growing environment, so that growth will be better. Although extensive management and casual planting can allow them to survive, artificial cultivation is meant to provide the best growing conditions. I do not know what you think, but you can refer to this and adjust it in combination with your own understanding.