Yasumaru Hirai

Delivery System of Tracing Caplets for Wheat Grain Traceability

The system for delivering tracing caplets into grain on a combine was developed as a part of a grain traceability system. A commercially available seed dispenser was utilized to meter tracing caplets into wheat in the combine bin tank during the unloading process. The caplets were delivered into the grain stream close to the unloading auger to attain uniform distribution. The distribution uniformity of caplets was sampled on five consecutive bin loads, with six 1-L grain samples from each load. The number of caplets in the samples was reasonably consistent at unloading time of 20 and 30 s when the grain unloading rate was stable. However, caplet concentration increased as grain flow was reduced at the beginning and end of each unloading event and caplets that remained in the grain tank sump after each test was discharged in high concentrations at the beginning of the subsequent unloading process.

Development of a remote environmental monitoring and control framework for tropical horticulture and verification of its validity under unstable network connection in rural area

Display Omitted Remote monitoring and control framework under unstable network connection.The framework consists of local and global management subsystem.Evaluated on tropical horticulture monitoring and soil moisture content control. This study focuses on the development and evaluation of a remote field environmental monitoring and control framework, implementing a local-global management strategy to overcome the unstable network connection in the rural area. The framework consists of environmental monitoring and control node as the local management subsystem (LMS), and the web data providing and system management as the global management subsystem (GMS) to establish a simple and flexible remote environmental monitoring and control based on a cloud platform. The supporting features are online and offline environmental monitoring, synchronization of system configuration, actuation, and offline management. Two field tests were conducted to verify its performances and functionalities, (1) environmental monitoring on tropical horticulture cultivation in Yogyakarta, Indonesia, and (2) implementation of the monitoring and control for automatic drip irrigation control based on soil moisture content for tomato. As the result of the first test, the developed framework could help to maintain the sustainability of environmental monitoring under unstable network connection over 80% availability of the data with local offline measurement up to 24% of the total entries. From the second test result, the framework could support the real-time monitoring and control of soil moisture content as well as increase the system flexibility in the adjustment of the system configuration remotely. The control system has 0.78% error (E) and 99.2% in-range soil moisture content (L

Development of Actuation Framework for Agricultural Informatization Supporting System

Abstract Agriculture faces many challenges in the production system, such as climate and weather, field conditions, crop types, soils types and conditions, and so on. Farmers consider many aspects to optimize the “on-farm” process by their long-term experiences. Various informatization agricultural supporting systems have been developed using ICT (Information and Communication Technologies) to improve agricultural productivity. Authors have developed the ICT-based agricultural supporting system called the “Agri-eye” in which a field monitoring, crop growth and quality evaluation, work recording, and online data offering and sharing sub-systems were incorporated. On the other hand, an actuation sub-system for controlling and managing agricultural facilities in a greenhouse such as a heater, water pumps, circulation fans, a CO 2 generator, etc. has been introduced. In this study, an actuation framework is developed as a useful method for monitoring and controlling local facilities and machineries. The method can be used for controlling particular device with adjusting parameter from Agri-eye server to meet the cultivation requirement. Furthermore, the validity of the developed framework was verified to monitor and control air temperature in laboratory test box.

Structure of thermal convection development based on inhomogeneous water surface cooling

The generation and development of thermal convection based on inhomogeneous water surface cooling were examined by hydraulic and numerical experiments to examine the characteristics of thermal convection in a closed water body with aquatic plants. A visualization experiment revealed the structural characteristics of a whirlpool when thermal convection was generated quantitatively by using PIV analysis. Then, a water temperature measurement experiment demonstrated that a steady cold water mass generated based on the heat flux transport from the water surface increases. This explained each of the three stages in the convection development process. Moreover, aquatic plants, which grow thickly on the water surface, cause not only vertical but also horizontal flows based on the density difference with the water surface that is not covered by plants, and thus change the development process of the convection cell.

Loss Evaluation of Soybean Harvesting on Four Types of Headers

Soybean header losses were evaluated on four header configurations: rigidheader, flexible header, row crop header, and rigid header with milo guards. The formerthree headers have commonly been used for soybean harvesting. The results of fieldtests showed the lowest loss in the rigid header followed by flexible header, row cropheader, and rigid header with milo guards. The evaluation results were different fromthose previously reported, which typically found the least loss with a row crop headerfollowed by flexible header and rigid header. The difference of header losses amongfour headers was not statistically significant. For the effect of the milo guard on headerlosses, the advantage on all kinds of losses, which include stalk, stubble, lodged, andshatter losses, was not shown.

Numerical Analysis of the Reaction Force of a Single Rice Stalk undergoing Forced Displacement

In this study, the reaction force of a rice stalk undergoing forced displacement was analysed based on a mechanical model of a crop stalk. Horizontal and vertical reaction forces of a single rice stalk undergoing forced displacement were measured. The horizontal force increased linearly for small curvatures of the rice stalk; after that, force increments decreased with displacement due to large curvature of the stalk. The vertical reaction force had different tendencies, depending on the initial shape of the rice stalk. The main reason for the differences was a directional change in friction, depending on the initial shape. An intrinsic shape function of a rice stalk was proposed. An equation of curvature describing rice stalk bending was derived by considering the curvature due to intrinsic shape, and used for analysis of the reaction force. The analytical results coincided fairly well with measured values, and it was demonstrated that the reaction forces of a single rice stalk according to the initial shape was accurately predicted by numerical calculation.

Effects of different application methods of fertilizer and manure on soil chemical properties and yield in whole crop rice cultivation

ABSTRACT Whole crop rice (WCR) is expected to establish a cultivation method using manure produced from animal wastes. Meanwhile, application methods of fertilizer and manure in the WCR cultivation are affected by availability of manure, available time for its application, and field drainage, and low market price of WCR. This raises concerns about soil fertility deterioration and yield reduction in the WCR cultivation. The objectives of this study were to investigate how different application methods of fertilizer and manure affected soil chemical properties and yield in the WCR cultivation. Field surveys were conducted in 2013 and 2014 at 10 fields cultivated by five different farmers in the Itoshima region, Fukuoka Prefecture, Japan. The surveyed fields included two application methods of manure (M) alone and chemical fertilizer (CF) alone. Clay plus silt content was significantly correlated with total nitrogen (TN), total phosphorus (TP), and exchangeable potassium (Exch. K), which indicated that soil texture partly contributed to the variations of these soil chemical properties. Meanwhile, clear gaps of TN, TP, Exch. K, K saturation degree, and available N between CF and M at around 40% of clay plus silt content strongly suggested that manure application contributed to increases in the soil chemical properties. Yearly differences of available N had relatively large negative values in CF fields. This result suggested a possible decrease in mineralizable part of soil TN in the WCR cultivation with CF alone, which needs to be clarified through long-term study. Significant relationships between potential N supply and straw weight (r = 0.698, p < 0.05 for 2013; r = 0.873, p < 0.01 for 2014) or yield of whole crop (r = 0.852, p < 0.01 for 2014) indicated that N mineralized from soil, which was enhanced by manure application, increased straw weight, resulting in an increase in yield of whole crop. However, excessive amounts of manure applied in surveyed fields can cause groundwater and surface water pollution. Thus, nutrient balances in a paddy field need to be analyzed further to determine an appropriate application amount of manure.

Impact of luxuriant aquatic plants on thermal convection in a closed water body

The attenuation of heat flux at the water surface with aquatic plants was examined by hydraulic experiments to consider the influence of aquatic plants on the magnitude of thermal disturbance in the closed water body. First of all, the experiment measuring temperatures on surface of leaf revealed the thermal conductivity of the leaf which is peculiar physicality of each aquatic plant. Then, the hydraulic experiment examined attenuation of the underwater illuminance and the heat flux in the covered part which depending on the kind and the luxuriant density of the aquatic plants. As the result, it is clarified that the attenuation rate of the illuminance is large in the plant with a thick leaf, and that the heat flux at the water surface and the developmental velocity of the mixed layer decreased when the luxuriant density of the aquatic plants increased.

A “Proof of Concept” Delivery System for Grain Tracing Caplets on the Combine

The system for delivering tracing caplets into grain on a combine was developed as a part of the grain tracing and recall system. A commercially available seed dispenser was used to meter tracing caplets into wheat in the combine bin tank during the unloading process. The caplets were delivered into the grain stream close to the unloading auger to attain uniform distribution. The distribution uniformity of caplets was sampled on five consecutive bin loads, with six one-liter grain samples from each load. The number of caplets in the samples was reasonably consistent at unloading time from 10 to 40 sec. when the grain unloading rate was stable. However, caplet concentration increased as grain flow subsided at the end of each unloading event.

REACTION FORCE OF WHEAT STALKS DURING THE REEL OPERATION OF A COMBINE HARVESTER

The purpose of this study is to clarify gathering operations appropriate to crop conditions, such as a crop’s physical properties and the extent of lodging, from viewpoint of the mechanical interactions between crops and a combine harvester reel. Because the gathering process by the reel involve the mechanical operation of forced displacement, the reaction force of a bunch of wheat stalks undergoing forced displacement was analyzed in our previous study, and the result has been verified by the experiment under a quasi-static loading rate. In the present study, in order to investigate the effect of loading rate and to discuss the application of the analytical method, which is valid under a quasi-static loading condition, to the actual reel operation, the reaction force of a bunch of wheat stalks was measured under several different loading rates by the experiment involving gathering operation of the reel. As the results, the horizontal reaction force increased its values in the negative x direction together with an increase in loading rates, and the analytical results had a large amount of error under high loading rates. The above result was examined in terms of the acceleration of forced displacement during the gathering operation. The acceleration increased its values in the positive x direction together with the increase in loading rates, and the peak of acceleration coincided with that of reaction force. From these results, the main reason for the increase in the reaction force was considered to be an effect of the inertia force of a wheat stalk caused by forced displacement involving the acceleration, and a subject of the current analytical method for applying to the actual reel operation was clarified.