Chlorophyll meter informs watermelon of its abundance of nitrogen Nitrogen is one of the main nutrients that affect crop growth and yield. The nitrogen status of crops is closely related to their yield and quality traits, and the diagnosis of nitrogen nutrition has been the main content of crop nutrient diagnosis. In recent years, the application of chlorophyll meter has achieved good results in indirect rapid measurement of crop nutrient, and the SPAD value measured by chlorophyll meter can indirectly reflect the content of chlorophyll in crop leaves and the nitrogen content of crops, and can further predict the yield of crops. , And used to guide top dressing. At present, chlorophyll meter has been applied to the diagnosis of nitrogen nutrition in rice, wheat, corn, cotton, potato, cucumber and other crops, and also guides the implementation of fertilization. Research shows that by measuring the chlorophyll meter, we can save 10% of the fertilizer application amount without affecting the yield. a. Determination of leaf nitrogen content. The sample for the determination of nutrient elements shall remove impurities that may adhere to the root surface. Before sampling, clean the roots with clean water, and then dry the water with a clean soft paper. After measuring the length and quality of the root, place the remaining envelopes on the kraft paper in a constant temperature blast. Drying machine 105 °C fixation for 30 min, then 70 °C dry to constant weight, grinding, mixed by acid (95% concentrated sulfuric acid and 5% perchloric acid) digestion, constant volume and filtered to clean, dried plastic Bottles, total nitrogen content in leaves of each sample was determined with a flow injection analyzer (FLAstar 5000, Sweden). b. Determination of leaf chlorophyll SPAD values. A SPAD-502 chlorophyll meter produced in Japan was used to measure the SPAD values ​​of the leaves at different leaf positions in the fully expanded leaf every 2 cm, and the average value was taken as the SPAD value of each leaf. Measured once a week. Finally, compare the results of the two measurements. The total nitrogen content of plant leaves can well reflect the nitrogen status of crops and it is a good diagnostic indicator. According to the nitrogen content of leaves, the lack and excess of nitrogen nutrition in watermelon can be determined accurately. Through the dynamic monitoring of SPAD values ​​during the growing period of watermelon, the SPAD values ​​of the upper, middle and lower leaves of watermelon showed a certain regularity at each level of nitrogen application. When the nitrogen application rate is low (nitrogen deficiency), the chlorophyll meter measurement value increases with the nitrogen supply level, but when the nitrogen supply reaches a certain amount (normal nitrogen supply N4 ~ N5), then increase the nitrogen supply amount (nitrogen excess ) The chlorophyll meter readings of watermelon leaves do not change much. When the crop is in a state of luxury absorption, the chlorophyll content no longer increases with the increase of nitrogen application. Therefore, when using the chlorophyll meter to monitor the nitrogen status of crops, it can reflect the nitrogen deficiency status of the crops. The results of this experiment showed that the SPAD values ​​of different leaf positions in different leaf nitrogen positions, different growth stages, and the same nitrogen level were different in the same leaf position of watermelon. This indicates that when performing nitrogen nutrient diagnosis, the growth period and the leaf position of the crop should be taken into account, ie nitrogen sensitive period and sensitive leaf position. Referring to previous research methods, the correlation analysis found that the SPAD value of the upper leaves and the extension lower leaves of the watermelon at seedling stage was significantly correlated with the nitrogen content of the leaves, and then the best application of SPAD value for the diagnosis of watermelon nitrogen nutrition was determined. The period of measurement and the site of measurement were the upper leaves of the seedling stage and the lower leaves of the extension period. This provides a basis for the rapid diagnosis of nitrogen nutrition in watermelons and reduces the problem of large workload and poor timing in indoor analysis. It also made it possible to apply fertilization measurements to Daejeon Watermelon in order to guide agricultural production. This study also found that the SPAD value of the upper leaf during the fruit expansion period was significantly correlated with the yield of watermelon and could be used to predict the watermelon yield. Stunt Scooter,Adult Stunt Scooter,Invert Scooter,Pro Stunt Scooters Jinyun County Longma Automobile Electric Co., Ltd. , https://www.longmaauto.com
Chlorophyll meter informs watermelon of its abundance of nitrogen