Abstract:
Protected horticulture in intensive mode has rapidly promoted agricultural production in recent years. However, the soil is prone to breeding pathogenic bacteria and pests under the long-term temperature and humidity environment of protected horticulture crops. In addition, continuous cropping of soil can accumulate pathogenic bacteria, resulting in the frequent occurrence of soil-borne diseases and pests, which seriously restricts the high-quality development of the protected horticulture industry. Soil disinfection is often required to prevent and control soil-borne diseases and pests, and even to break down the obstacles of continuous cropping. However, there are still challenges with dazomet soil disinfection equipment. It is necessary to solve the low uniformity of pesticide application, complex procedures, and difficult coverage in the edge area of soil disinfection in a greenhouse. In this study, intelligent soil disinfection equipment was developed for the combined operation of air-conveying dazomet, rotary burying, and film mulching in the greenhouse. The machine also integrated the functions of pesticide application, rotary tillage, film mulching, and bias. The uniform distribution of dazomet was realized in the operating width and forward direction under the air-conveying mode. The dosage was controlled according to the vehicle speed feedback variables. The whole disinfection of the narrow area was realized at the edge of the greenhouse. An optimal combination of parameters was determined, including the rotary tillage, air conveying application, film mulching and lifting offset. Specifically, the rotary tillage depth was 16.8 cm, the rotating speed range of the chute wheel was 10-26 rpm, and the film mulching eccentric swing device realized ±45° back-and-forth swing and two film mulching. A series of tests were conducted to verify the pesticide application performance of rotary tillage and offset. The results showed that the errors between the application depth and operation width of rotary tillage and their theoretical values were less than 3.3% and 0.3%, respectively. The variation coefficient of rotary tillage depth stability was not more than 2.81% under different lateral offsets. The performance was both stable. Then, the static test was conducted to construct the pesticide application dosage model. The variation coefficient of the stability of the total pesticide application dosage was not more than 2.53% under different sheave speeds, while the variation coefficient of the consistency of pesticide application dosage in each row was not more than 4.77%. Furthermore, field experiments were conducted to investigate the effects of forward speed and inlet wind speed on the distribution uniformity of dazomet. The inlet wind speed was the dominant factor affecting the horizontal distribution uniformity, with the optimal value of 6 m/s, and a minor effect of forward speed. The coefficients of variation of lateral and forward directions were 22.93% and 8.02%, respectively, under the optimal parameters. The performance of the whole machine can meet the agronomic requirements of greenhouse dazomet soil disinfection. The findings can provide a theoretical reference for developing intelligent equipment for soil disinfection.