Fruits Vegetables' Fertilization

Protected vegetables have entered the fruitful period and have entered the peak period of water absorption and fertilizer absorption. Therefore, we should fully understand the requirements of the fruit and vegetable crops during this period so that scientific and rational fertilization can be applied.

The proportion of nitrogen, phosphorus, and potassium absorbed during the peak of fruit growth is different from that before the growth. At this time, more potash fertilizer is required, the demand for phosphate fertilizer is stable, and the demand for nitrogen fertilizer is increased, but the demand for nitrogen is lower than that of potassium. In conversations with farmers, we found that they generally believe that phosphate fertilizers, urea, and ammonium bicarbonate can be used as fruit fertilizers; and it is believed that the more fertilizers, the higher the yield. This results in over-application of nitrogen, excessive application of phosphorus, and insufficient potassium fertilizer in the fruit stage.

When there is too much nitrogen fertilizer, it is often found that the leaf area is increased and the leaf color is dark green. In severe overdose, the plant leaves are thick and hard, the leaves are twisted, the fruits are reduced or the melon strips are twisted and other salty symptoms.

When there are too many phosphate fertilizers, chlorotic symptoms such as zinc deficiency, iron deficiency, and magnesium deficiency will occur because the dissolved phosphate will combine with these elements in the soil and reduce their effectiveness.

In the absence of potassium, the lower old leaves will appear scorched from the edges, the fruits will crack easily, the sugar content will be reduced, the flavor will be worse, and the plants will have premature aging. Therefore, we suggest that fertilization at fruit stage should follow the principle of a small number of times and pay attention to the application of potash fertilizer. When it is necessary to supplement trace elements, it can be carried out by foliar spraying.

In addition, as the temperature of the greenhouse increases, it is sometimes observed that the tomato's umbilical rot or the cucumber's top is brownish. This is caused by calcium deficiency.

When the greenhouse temperature rises too fast and the temperature changes drastically, the water absorption of the plants will be difficult, affecting the transport of calcium in the plants and causing calcium deficiency at the top. The solution is to adjust the temperature inside the shed to prevent it from falling too high, watering in time, and spraying with calcium fertilizer.

As the outdoor temperature rises, the number of viral vectors such as aphids and whitefly increases, and pest control should be emphasized to reduce the occurrence of viral diseases. Adding pest control nets is an effective and economical measure. It should be noted that colorless insect nets are added to all ventilation openings in greenhouses. A disinfectant pool is set up at the entrance of the greenhouse, and lime is placed inside to disinfect the sole. A bottle of 10% trisodium phosphate or 0.1% potassium permanganate disinfectant was prepared in the greenhouse for the disinfection of the hands. Controlling aphids can use 25% of Aketai 7500-10000 times spray. All these measures can reduce the spread of viral diseases to some extent.