In November, yuanmou tomato showed a large area of premature aging, yellowing, leaf curling, drying, and root growth dysplasia, resulting in decreased tomato yield in this area and even death from drying.
1. Possible causes of yellowing are as follows:
1. The climate factors affecting large: climate data analysis through combining with the previous year, the abnormal weather this year, than in the past few years greatly reduced rainfall, recently there was no rain for more than two months, for a long time in the climate of high temperature and light, day and night temperature difference is too large a recent night temperature is too low, temperature rise quickly, at noon, lead to plant leaf cell dehydrate, causing premature aging yellowing.
The temperature requirements of tomatoes in different growth cycles are: 25 to 30 degrees for germination, 20 to 25 degrees for seedling (10 to 15 degrees at night, 0 to 3 degrees for exercise), 20 to 30 degrees for flowering (15 to 20 degrees at night), 25 to 28 degrees for fruit (15 to 20 degrees at night), and 20 to 22 degrees for soil temperature. Growth ceased above 35 degrees and normal physiological activities were disturbed above 45 degrees.
2. Insufficient soil moisture: due to low rainfall from seedling stage to fruiting stage, high temperature weather for a long time, and large evaporation of soil moisture, the plot is hard, and farmers habituated to drop water every 7-10 days, resulting in insufficient soil moisture, insufficient root system vitality, and insufficient nutrient elements.
3. Soil PH value factor: according to the soil survey data, the proportion of PH above > 7 is more than 80%. The growth of plants in alkaline environment can hardly absorb trace elements. When salinity is higher than the tolerance range of the plant, the plant will not be able to grow normally, resulting in poor root growth, and even burning roots, nutrients can not keep up with other problems.
The absorption of various elements in the optimal PH range, the PH value of most nutrient elements is relatively easy to be absorbed between 6.5 and 7.5, the absorption of medium elements is better under alkaline conditions, and the absorption of trace elements is easy to be absorbed under acidic conditions except molybdenum which is between 6.5 and 8.5. The optimum PH of tomato is between 6.0 and 7.0, and about 7.5 to 8.
4. Water quality factors: yuanmo water quality is poor, and the PH value is high or low, mainly because the Ec is too high and has exceeded the Ec of fertilizer solution, which has a great impact on soil, nutrient element absorption and pesticide application effect
5. Salinization of soil: the temperature is too high for a long time, and the deep water in the soil contains some salt. As evaporation at high temperature accumulates the salt in the soil surface, the high temperature for a long time causes the soil salt to become higher and higher. In tomato soil, EC grows normally at 2.5 and is not exposed to salt damage.
Ii. Suggested prevention methods and measures:
1. Maintain soil moisture: change the time of dripping from 7-10 to 4-6 days, and increase the frequency of 1-2 times of dripping. Grow the roots well from the seedling stage and make the plant strong. Only if the plant is strong and resistant will it be good. Drop water before applying fertilizer in high temperature to avoid loss of fertilizer.
2. Soil improvement measures: add bio-organic fertilizer and microbial agent fertilizer. Supplementary bacterial fertilizer: biological bacterial fertilizer is rich in a large number of beneficial bacteria in the soil, the beneficial bacteria in biological bacterial fertilizer can also play a role in phosphorus, potassium, nitrogen fixation, etc. to improve soil quality, improve soil microecological environment, reduce continuous cropping obstacles.
Recommend crop rotation where rice can be grown; The mountainous area that cannot grow rice: sow green fertilizer (there is rain in may-august) or plant dry season crop, also can straw returns the field.
3, water quality improvement: acid can be solved, but in retail is not safe and feasible. At present recommend: add good farmland to soften water quality + fertilizer or pesticide first, can alleviate slightly.
4. The use of chemical fertilizers should adhere to the current principle: appropriately adjust the formula and dosage in different periods, strengthen the supplement of medium and trace elements, and not blindly increase the dosage of chemical fertilizers to increase the yield.
The above analysis is entirely personal, if you have better ideas or Suggestions, I hope you can leave questions in the comment area, we try our best to help answer!