The transformation and upgrading of traditional agriculture are required to address its shortcomings and deficiencies, which have resulted in environmental pollution or water problems. Precision agriculture emerged at the historic moment to solve the current problems. Field information collection, information management and decision-making, and execution systems are the three key links of precision fertilization and irrigation. The technical principle and application of field information acquisition systems are analyzed. The information management and decision-making system describes the management and summary of information in crop growth. The execution system combines the knowledge of various disciplines and experts for targeted applications to specific crops. It further focuses on the core implementation system, that is, variable fertilization technology and variable spraying technology that can realize variable operations. Major contributions from different countries, institutions, corresponding authors, and journals are presented in detail. This study proposes several suggestions and ideas based on the research status and progress of the three key systems to provide a theoretical basis and technical support for the research and development of key technologies and innovative devices of precision agricultural fertilization and irrigation.

Sandy clay loam has the characteristics of both sand and clay. Because of these characteristics, both frictional resistance and adhesive resistance occur between the soil and tillage tool. The combined effect of the two frictional forces increases the external friction angle between the soil and tillage tool, thus increasing the working resistance. To address this issue, this study investigated the coupling effect of high pressure and hot air on the external friction angle by using a self-developed device to measure the external friction angle. Test results showed that high-pressure air between the soil and tillage tool formed a high-pressure air curtain layer which acted as a lubricant, thereby reducing the external friction angle. The external friction angle decreased as the airflow pressure increased. The reduction in the moisture content of the subsoil to less than 30% by the high-pressure hot air reduced the resistance between the soil and tillage tool. The approach with the high-pressure hot air curtain was verified in tests on a subsoiling shovel; the working resistance of the shovel under high-pressure hot air was reduced by 14.8%, demonstrating that this approach was effective in reducing the working resistance of the shovel.

Small, handheld furrow openers using rotary blades usually have limited power, making it necessary to minimise their operating power consumption, which mainly occurs with the soil throwing and movement of rotary blades. To this end, it is necessary to investigate the power consumption of such tillage implements, particularly the relationship between their power consumption and operating conditions based on soil movement patterns. In this study, we performed a field test of a furrow-opening rotary blade using round, physical tracers to monitor soil movement. The total power consumption of the rotary blade was positively related to the operating depth of the blade but was not related to the soil movement distance. The total power consumption peaked at 6.677 kW at a forward speed of 0.3 m/s, which was negatively related to the forward speed, but positively related to the soil movement distance. At a blade rotational speed of 340 rpm, the total power consumption peaked at 4.385 kW and was positively related to the blade rotational speed and soil movement distance. Therefore, it was concluded that by decreasing the rotary blade rotational speed and operating depth and increasing the forward speed, the power consumption of the unit working length can be reduced.