Transactions of the Chinese Society of Agricultural Engineering, the 1st in Agricultural Engineering, is supervised by China Association for Science and Technology, and sponsored by Chinese Society of Agricultural Engineering. It aims to introduce the latest scientific achievements and developing trends of Agricultural Engineering and provides the academic developments abroad and domestic of the discipline. The scope covers agricultural water-soil engineering, agricultural information and electrical technology, agricultural products processing engineering.
The journal is included in EI, JST, Pж(AJ), CA and CSCD.
Editor-in-Chief Zhu Ming
Deputy Editor-in-Chief Wei Xiuju Zhang Ruihong Xi Weimin Wang Liu Wang Yingkuan Li Pingping Ying Yibin Tong Jin Yun Wenju Zhao Chunjiang Kang Shaozhong
Since 2004, with the rapid rise of labor prices, the application of agricultural machinery in China’s agricultural production has increased and the process of agricultural mechanization has been rapidly advancing in the“golden decade”. It is a research subject with both theoretical significance and policy reference value to explore the substitution of labor by agricultural machinery during this period, and to study the phased characteristics and continuity of factor substitution. Based on the provincial panel data from 2004 to 2016, this paper uses the translog cost function to calculate the substitution elasticity between machinery and labor in the production of three major grain crops, i.e., wheat, maize and rice, focusing on the difference between crops and between regions, and their spatial and temporal variations. The data used in this paper come from
National Agricultural Product Cost And Income Data Compilation of China, and
China Statistical Yearbook (2002–2017). The results show that: 1) The development of China’s agricultural mechanization experienced a “golden decade”, mainly due to the widespread, effective, and sustained replacement of labor by agricultural machinery, the substitution elasticity between agricultural machinery and labor for wheat, maize and rice was 0.581, 1.324 and 1.153, respectively, and the mechanization of maize and rice at key production link is remarkable. 2) The substitution elasticity of wheat was stable at around 0.6 during 2004–2016, while the substitution elasticity of maize and rice showed a long-term downward trend, which decreased from 1.545 and 1.224 to 1.225 and 1.152 respectively. It means that when agricultural mechanization reached a higher level, the difficulty of factor substitution gradually increased and the substitution elasticity tended to decline, and it is much more difficult to increase the mechanization level of grain crops in the future. 3) Affected by the factors such as the topography of operations, the development of agricultural mechanization in various provinces is at different stages, and there is a clear difference of the substitution elasticity between agricultural machinery and labor in grain production. The substitution elasticity of the southern low-lying hilly region, and the hilly and mountainous area in the southwest is generally higher than those in other regions, and there is a large space to increase the agricultural mechanization level in these regions, which might keep a remarkable increase. 4) With the general increase of mechanization level, the substitution elasticity shows the characteristics of temporal and spatial convergence, and the regional differences are gradually reduced and the whole tends to be stable. This can be used to explain the slowdown of the speed of China’s agricultural mechanization, and it also means that relying solely on the mechanization of food crops to stimulate the overall level of agriculture mechanization has become a thing of the past. In the future, the rapid growth of agricultural mechanization in China is faced with unprecedented difficulties and challenges, and it needs five aspects of measures to deal with this situation, such as enhancing the mechanization level of hilly and mountainous areas, promoting the mechanization toward whole and entire development, promoting the using of new multi-machinery and information-based smart machinery through machinery purchase subsidy policy, and reducing operational links and labor force participation directly.
Wolfberry (
Lycium barbarum) is a plant of Solanaceae. Studies have shown that the LBP has many effects, such as delaying aging, anti-tumor, anti-fatigue, controlling blood sugar, and preventing glaucoma. The main producing areas of wolfberry are Ningxia, Inner Mongolia, Xinjiang, Hebei, Qinghai, Hubei, and Tibet. In recent years, wolfberry area has been increasing by 11% annually. Wolfberry has indefinite inflorescence, and the end of June to early October is the picking period of wolfberry. Wolfberry is in continuous flowering during the picking period, and the average picking cycle is seven days. Wolfberry picking is still artificially, so low efficiency and high labor cost are the most prominent issues. The efficiency of artificial picking wolfberry is only 3–5 kg/h, while the cost is up to CNY 34 500 per hectare, accounting for more than 50% of production cost. With the growing area of wolfberry, the labor force will be in short supply, so the picking problem has become the bottleneck restricting the sustainable development of wolfberry industry. Wolfberry is less cultivated abroad, so there are few studies on large-scale cultivation and mechanized picking of wolfberry in foreign countries. The research on wolfberry picking machinery in China began in the early 21st century and was carried out mainly in several major producing areas. At present, according to the different principles of picking, wolfberry picking machinery can be divided into four main types: shear, brush comb, vibration, and air flow. However, the current various picking machinery has obvious defects. In this study, we designed a vibrating wolfberry harvesting device with comb brush bases and tested its performance. The device consists of harvesting unit and lifting mobile unit. The harvesting unit includes comb brush vibration mechanism, DC motor, timing pulley, support frame, and baffle. Among them, the comb brush vibration mechanism is the key component, which including left input shaft, right input shaft, harvest rod, T reducer, disc, connecting rob, coupling, slider, and sliding shell. The four rows of harvesting poles and the shell are fixed by bolts. The shell and the slide are also fixed by bolts. The slide rail and the slider are matched with each other so as to make linear motion along the slider. The two ends of the connecting rod are respectively hinged with the shell and the disc. The harvesting unit is used to achieve the recovery of wolfberry fruit. Lifting mobile unit is a hydraulic lift trolley. The harvesting unit is fixed on the lifting mobile unit, and the whole harvesting device can move horizontally and vertically. Based on ADAMS software, the model of
L. barbarum fruit and branch, the model of comb vibration are established by parameterized modeling. The connecting force between fruit and fruit stem is connected by the generalized force. The sensor is used to monitor the fruit stem breakage condition, which realizes the process control of separation of wolfberry fruit and stem. Through the simulation analysis, it is determined that the brushing speed, the disc speed (vibration frequency) and the vibration amplitude of the harvesting device have significant effects on the shedding of wolfberry fruit. The field experiment was carried out to evaluate the harvest efficiency, the harvest rate of mature fruits, the shedding rate of immature and the damage rate of mature fruits. The test results showed that the best combination was that the comb brush speed at 80 r/min, disc rotation speed at 100 r/min, and vibration amplitude at 80 mm. Based on the combination of the factor level, the harvest efficiency was 13.12 kg/h, the harvest rate of mature fruits was 87.46%, the shedding rate of immature fruits was 13.81%, and the damage rate of mature fruits was 2.82%. Compared with other single-principle harvest mechanisms, the device not only achieves harvest efficiency and higher mature harvest rate, but also guarantees relatively low shedding rate of immature fruits and damage rate of mature fruits. This study can provide a theoretical basis and data support for the design of the mechanized harvesting machinery of wolfberry.
Aerobic composting is an important technical approach to the harmless resource utilization of livestock and poultry waste. In actual composting, a certain amount of amendments should be added to promote the effective operation of aerobic composting. At present, the amendments are divided into active and inert ones from the angle of participating in the fermentation process. The effect of active amendments on improving the reactor structure is not obvious, and the carbon-to-nitrogen (C/N) ratio of inert amendments could not be regulated. This study aimed to realize the diverse functions of amendments, such as regulating the chemical properties of compost material and improving the heap structure. The non-sufficiently carbonized woodland wastes (e.g., branches) were used as carbonaceous amendment (CA) to improve the quality of manure aerobic composting. The granule surface of CA material was carbon and the interior was still wood structure. The feedstocks for composting were mainly pig manure and edible fungus residue. Three treatments included the CK (pig manure and edible fungus residue as compost), B1 and B2 [60% (volume ratio) of edible fungus residue in CK was replaced by the CA with a particle size of 1–2 cm and 6–7 cm, respectively]. The composting treatments were in triplicate and lasted for 30 days. The changes in temperature, ammonia volatilization, nitrous oxide emission, pH value and EC value during composting were monitored. Days of heating up to 55 °C for the first time, nitrogen loss rate, C/N change rate, seed germination index and the recovery rate of amendment were selected as the evaluation indexes, and the application effect of CA in composting was analyzed by the fuzzy evaluation method. Compared with the control, CA could obviously promote the rapid increase in heap temperature, reduce the days of heating up to 55 °C for the first time by 4–11 days, and significantly raise compost accumulated temperature. The heating and warming effect of B2 treatment was better than that of B1 treatment. After 30 days of composting, the total ammonia volatilization amounts of three treatments (CK, B1, B2) were 605.41, 374.94, and 303.68 mg/kg, and the accumulated nitrous oxide emissions were 35.80, 49.53, and 74.94 mg/kg, respectively. The nitrogen loss rates of B1 and B2 treatments decreased by 16.13% and 22.81%, respectively. The decrease in nitrogen loss in composting was mainly due to the effective control of NH
3 volatilization. CA reduced the EC value of the compost, significantly improved the C/N change rate and the seed germination index. The comprehensive comparison of various indexes and fuzzy evaluation results indicated the composting effect of B2 treatment was better than that of B1 treatment. CA could effectively promote the decomposition of pig manure and improve the quality of composting products, and the suitable particle size of CA for aerobic composting with high temperature was 6–7 cm.
