It takes helio greenhouse to plant potatoes in North of China, and in Central China and Southwest of China it takes tunnels. There are lot of problems in planting, such as excessive fertilizing, and content of NPK fertilizer is high, which leads to soil acidification, and prevent supply of Ca, Mg and B and the absorption of quality. It must pay attention to the following points:
Control fertilizer volume of NPK and supply micronutrient such as Ca, Mg and B in non- limy soil or acid soil.
Fertilizing reasonably according to the output of crops, generally speaking, P fertilizer is as the base fertilizer and the N, K fertilizer to be as top application; in the early days of the growth stage, it is not very good to top dressing frequently, but it’s good after flowering and in the middle or later stage.
Match with the high-yield culture technique and promote root Irrigation in the seedling period, irrigating a little but in several times.
Degraded soil need to fertilize organic fertilizer with high proportion CN, to fertilize little farmland manure, and increase the crop rotation.
Fertilize the liming to release the soil acidification.
Ways of fertilizing and volume
1/ Supply P fertilizer and organic fertilizer in the seedlings period. 60-100kgs of farmland manure and 0.5-1kg Ca, Mg and P fertilizer, 0.5kg potassium sulfate for every 10 ㎡ soil. Spray 0.05-0.1% urea solution once or two times according to the growth of cereal crop seedlings.
2/ Fertilize organic fertilizer, volume is 2-3 cube for every 667㎡.
3/ Yield is 8000-10000kgs/667㎡ or above: N fertilizer（N）30-40kgs/667㎡, P fertilizer（P2O5）15-20kgs/667㎡, K fertilizer（K2O）40-50kgs/667㎡.
4/ Yield is 6000-8000kgs/667㎡: N fertilizer（N）20-30kgs/667㎡, P fertilizer（P2O5）10-15kgs/667㎡, K fertilizer（K2O）30-35kgs/667㎡.
5/ Yield is 4000-6000kgs/667㎡: N fertilizer（N）15-20kgs/667㎡, P fertilizer（P2O5）8-10kgs/667㎡, K fertilizer（K2O）20-25kgs/667㎡.
Generally speaking, vegetable need only a little magnesium fertilizer, but to the fruit vegetables, magnesium fertilizer is very important. Magnesium sulphate is quick-acting than other forms, it is better to be used as top application in the fruit Hypertrophy period. 20-30kgs magnesium sulfate is needed for every 10000㎡ soil for magnesium sulfate deficiency.
When soil’s PH<6, it’s lack of Ca, Mg and B, 50-75kgs lime (Ca fertilizer) and 4-6kgs of magnesium sulfate (Magnesium fertilizer) are needed to be base fertilizer for every 667 ㎡，fertilize 0.1% B fertilizer 2-3 times for outside root spraying. It’s better to fertilize magnesium sulfate as the base fertilizer before planting.