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A distributed seed delivery system is the most important component of a pneumatic central-cylinder seeder. We performed a fluent simulation analysis for seed-drop tubes at different parameters and airflow velocities, and with an increase in air velocity, the larger the angle is, the easier it is to produce a vortex, which considerably changes the angle, with the little bend tube improving the uniformity of seeding performance. The distribution of rice seeds in the seeding furrow using seed-drop tubes of different angles was also analyzed, and with an increase in delivery airflow velocity, the rice-sowing belts aggregated toward the seeding furrow central line, and with an increase in the forward speed, the seed distribution in the forward-speed direction presented an aggregation and then dispersion trend. The field experiment and physiological indices show that the yield of germination acceleration by seed pelleting can reach 7.92 t. ha−1, which was significantly higher than the yields with other treatments. [ABSTRACT FROM AUTHOR]

Grain qualities including milling, appearance, cooking and nutritional quality, are important traits that have aroused rice researchers' attention worldwide. Head rice rate, an important milling quality together with grain yield affects head rice yield. The head rice yield is directly related to economic value of the grains, and has significant impacts on income of rice producers. Precision rice hill-drop drilling is a simplified technique, which can achieve high yield while is applied at appropriate rice growth regions. The precision rice hill-drop drilling technique has been applied in many rice growth regions in China. Previously, precision rice hill-drop drilling technique has been proven to influence rice yield, agronomic performances and grain qualities in small region only and assessing the effect of precision rice hill-drop drilling technique on grain qualities in national wide is therefore important. In order to investigate the influence of precision rice hill-drop drilling technique on grain qualities in multiple rice growth regions in China, the comparison experiment were carried out. In this study, comparisons of the grain qualities between precision rice hill-drop drilling and machanical transplanting were investigated in the mainly planting areas (viz: Anhui, Shanghai, Guangdong, Sichuan, Xinjiang and Shandong) of precision rice hill-drop drilling in China. Results showed that precision rice hill-drop drilling technique was beneficial to improve head rice yield. Rice by using precision rice hill-drop drilling had higher head rice yield than that by using machanical transplanting in Nanling Anhui, Mianzhu Sichuan, Wensu Xinjiang, and Gaoqing Shandong regions, which increased by 9.11%, 27.02%, 4.08%, and 11.11% significantly. Moreover, the effects of precision rice hill-drop drilling technique on protein content and amylose content in grains from different investigated regions were different because of the difference in cultivars and environmental conditions, and the decrease in protein content and amylose content in grains were detected for some investigated regions. Furthermore, precision rice hill-drop drilling technique significantly decreased chalky rice rate in grains in Gaoqing Shandong, while showed no significant effect on appearance qualities of grains for other investigated regions. This study have investigated the impact of precision rice hill-drop drilling technique on grain quality of the rice varieties planted in large areas of the rice planting regions in China, this work is beneficial to further promotion to the popularization and application of precision rice hill-drop drilling technique in appropriate areas. [ABSTRACT FROM AUTHOR]

For centuries, strip compound planting system has been widely adopted in the southwestern part of China, and is mainly farmed by hand up to date. It is commonly believed that the compound planting system results to the low level of mechanization. The traditional strip compound planting system, "wheat-maize-sweet potato" (WMP) relay cropping system was once the main cropping pattern on dry land in this area. However, in recent years, along with the demand decrease of sweet potato as swine feed and the demand increase of soybean, soybean has been taking the place of sweet potato in the WMP system for its economic benefits; then the main compound planting system has gradually transformed into "wheat-maize-soybean" (WMS), which is now one of the key technologies the nation has been endeavoring to popularize. In the WMS relay cropping system, several rows of wheat are usually drilled with 20cm row space at the beginning of November of the first year relay-cropping with several rows of maize which are usually hill-dropped with 40cm row space at the end of March of the next year; when the wheat is harvested in the middle of May, several rows of soybean are then seeded with 40cm row space in the wheat stubble relay-cropping with maize at the beginning of June of the second year. In practice, there are usually three types of strip width configuration of Wheat-Maize: narrow (40-73 cm), medium (100-100cm, 117-83cm, 100-67 cm) and wide (200-200 cm). Different crop width configuration has different room available for mechanization operation; the nonstandard crop strip width hazards the adoption of mechanization; so the strip width configuration needs to be standardized firstly in line with the demands of mechanization. In order to realize the mechanized production of the WMS model as well as to improve the level of mechanization by popularizing the mechanized relay cropping system, the machine and agriculture measures for the WMS system should both be taken into account as a whole. On the condition of achieving the maximum annual yield of the three crops in the WMS system, field experiments have been carried out at several sites in the hilly areas of Sichuan Province since 2003 to acquire the optimal width configuration and agricultural measures. By the results, the "100-100" WMS model was selected as the optimal pattern to be mechanized with. Thereafter, mechanization operations were carried out in the chosen system by employing mini-, small- and medium-sized machinery system, respectively and the maize and soybean harvesters developed intentionally for the chosen pattern. According to the results, the mechanization of strip compound planting system is feasible; the compound planting system is not the root cause that leads to the low mechanization level in the hilly areas; "100-100" WMS model is the reliable carrier for developing dry land mechanization in the hilly areas of Sichuan; the Mini-four-wheeled tractor and its implements system is applicable for the strip compound planting system as well as the small-sized plots in hilly areas; so the popularization of the mechanized "100-100" WMS model shall facilitate the mechanization of the hilly areas. [ABSTRACT FROM AUTHOR]