A solid fertilizer and seed application rate measuring system for a seed-fertilizer drill machine

To achieve a precise seeding and fertilization control on a seed-fertilizer drill machine, it is essential to first realize accurate on-line measurement of the application rate for the machine. This study was focused on creating an on-line solid fertilizer and seed application rate measuring system based on the weighing principle for seed-fertilizer drill machines. The invented device consisted of a spring set and a weighing sensor, with its weighing mechanism, accurately measures the application rate of the seed-fertilizer drill machine. A real-time signal processing algorithm based on the low-pass filter, mean filter and adaptive Kalman filter was formulated based on analyzing field test results under various conditions. The developed device (with the on-line signal processing algorithm) was integrated to a commercial seed-fertilizer drill machine widely used on Jiangsu region of China and tested in field operations. The parameters being collected for assessing the performance of this developed system included the cumulative and the dynamic application rates in real time. In the cumulative rate measurement tests, this system was operated at three different seeding and fertilizing rates under two operating speeds of the machine. Obtained results showed that the maximum relative error of the cumulative application rate was 4.88%, and the average error of 2.62% with a standard deviation of 1.7% over about 2.5 ha of operation area. In the dynamic rate measurement performance tests, the device was operated at four combinations of seeding and fertilizing rates under two operation speeds. Under the condition of no seeding and fertilization, the average error of the dynamic application rate measurement was 3.15% with a standard deviation of 1.64% over about 2.2 ha of operation area. The seed-fertilizer drill machine was also tested on a wheat seeding operation, the obtained performance results showed that the application rate measuring system can provide the dynamic and cumulative performance information of the seed-fertilizer drill machine. The fluctuation degree of dynamic application rate can illustrate the dynamic regulation performance of the machine. Obtained results verified that the developed solid fertilizer application rate measuring system could not only used to precisely measure application rate, but also used to provide a needed feedback information for accurately control the application via a closed-loop controller to the machine to achieve a variable rate application.