A. Sweet potato fertilization
The demand of sweet potato for nitrogen, phosphorus and potassium varies according to the reproductive period.
(1) Nitrogen fertilizer
It is absorbed more during the period of stem and leaf growth and less during the period of tuber expansion.
(2) Phosphorus fertilizer
Less absorbed in the middle of stem and leaf growth, more absorbed in the period of tuber expansion
(3) Potassium fertilizer
Potassium fertilizer is absorbed more than nitrogen and phosphorus from planting to harvesting, and it is more significant in the period of tuber expansion.
is more significant. Therefore, sweet potato fertilization should be based on this characteristic.
B. Sweet potatoes with sufficient base fertilizer
The same base fertilizer should be based on farmyard manure plus microbial fertilizers, supplemented by chemical fertilizers. Therefore farmyard manure should be well rotted.
1. Base fertilizer selection
You can choose to use chicken manure, pig manure, cow manure and other human and animal manure. Use fertilizer fermenters for rotting.
Ripening. Rotting is fast and thorough, and is generally completed in about 10 days.
2. Amount of base fertilizer farmyard manure
The amount generally accounts for 60%-80% of the total fertilizer application. Generally speaking, 667 square meters of fresh potatoes 2500-4000 kg should be applied 3000-4000 kg of farmyard manure. Biofertilizer 2-3 kg / mu
3. Microbial bacteria intestinal role
Microbial bacterial fertilizer mainly serves to improve the soil. Activate the fixed phosphorus and potassium elements in the soil through microorganisms, etc. Resist heavy stubble, prevent soil slumping and improve soil salinization. Improve the utilization rate of chemical fertilizer, while achieving the purpose of increasing yield and income. And with the application of calcium superphosphate 15-25 kg, grass ash 100-150 Yu grams, ammonium carbon 6-10 kg, etc.
4. Base fertilizer
Firstly, a concentrated and stratified application should be used. Secondly 60% is applied to the bottom layer at the time of deep plowing and finally 40% can be applied in the hole at the time of planting.
C. Types and timing of common fertilization methods for sweet potatoes
①Sweet potato seedling raising fertilizer
Fertilizer is generally applied as a quick-acting fertilizer 3-5 days after planting, combined with seedling inspection and replenishment.
②Sweet potato seedling raising method
is to open a hole of about 10 cm near the root of the sweet potato seedling hole and apply a pinch of urea, i.e. l.5-3.5 kg per 667 square meters.
③After fertilization of sweet potato
Immediately after application, water and cover the soil, or use 1% urea water to irrigate the roots. To supplement the base fertilizer fast-acting fertilizer and the lack of slow fertilizer effect. At the same time, you can foliar spray spray into the fertilizer. Root seedling strong, or diluted directly for irrigation, can improve the survival rate of seedling spelling, sweet potato seedling rooting speed and number. Shorten the slowing period and achieve the purpose of strong seedlings superior in.
④Fertilizer for sweet potatoes with strong vines
When sweet potato enters the vine stage, the underground part of the growth potential becomes vigorous. The tubers start to form and have strong fertilizer absorption power. In order to accelerate the expansion of leaf area and improve photosynthetic production efficiency. Sweet potato should fertilized 30-40 days after planting.
⑤ Sweet potato fertilization amount
The amount of fertilizer should determined by ground strength and seedling potential, and more for poor growth. 7.5-10 kg of ammonium sulfate or 3.5-4.5 grams of urea or 4.5-6 grams of ammonium nitrate, l0 kg of potassium sulfate or 100 grams of grass ash should applied to 667 square meters.
⑥Sweet potatoes that grow well
The amount of fertilizer can reduced, combined with the fertilizer also in time to do a good job of weeding and irrigation to prevent drought.
⑦Sweet potato fertilization
Potato fertilizer should be mainly potassium fertilizer, generally applied 90-lOO days after planting. Potassium application during the potato promotion period
can effectively extend the functional period of leaves and enhance the vigor of stems and leaves. Improve photosynthetic efficiency and promote the operation of photosynthetic products,. Promote the expansion of organ blocks.
⑧Potassium sulfate for sweet potatoes
Generally, 10 kg of potassium sulfate per 667 m2 or 100-150 kg of grass ash can be applied. After application, it should be into a watering to promote its fertilizing effect as soon as possible.
⑨ Sweet potato cracking fertilizer
For sweet potatoes with obvious tendency of early failure during expansion, cleavage fertilizer has significant effect of yield increase. Crack fertilizer is generally 4-6 kg of sulfuric acid per 667 square meters and 400-600 kg of water. Or use 250 kg of well-rotted human manure and urine, 750 kg of water, and apply it along the cracks.
D. Sweet potato mid-expansion
Leaf and fertilizer Shao block mid-expansion, the root system began to decline in fertilizer absorption function. At this time should used outside the root of the method of fertilizer to supplement fertilizer. Generally use 2%-5% of calcium superphosphate leaching solution or 1% of potassium phosphate solution or 0.3% of potassium dihydrogen phosphate solution or 5%-10% of grass ash filtrate.
E. Sweet potato spraying method
Firstly, spray after 3:00 pm. Secondly, spray 75 kg of liquid per 667 square meters, and finally every 15 days, spraying 2 times in a row.
F. Notes on sweet potatoes
First of all, sweet potato is an anti-chlorine crop, the choice of fertilizer should be careful not to use fertilizers containing chlorine. Secondly, bicarbonate is not suitable for spreading and surface application, and can be made into mixed fertilizer granules for deep application. Finally, the application of animal urine should be fully rotted. The most important thing is that grass ash can not mixed with nitrogen and phosphorus fertilizer material, should be applied separately.