Effects of Waxy Types of a Sugarcane Stalk Surface on the Spectral Characteristics of Visible-Shortwave Near Infrared Measurement

Precision of spectroscopic methods were frequently affected by the identity of the inhomogeneous materials, especially for direct scanning. This research aimed to investigated effects of waxy types, naturally founded on cane surface, on spectral characteristic. A portable Vis/SWNIR instrument with interactance mode across wavelength of 570-1031 nm were used for direct scanning on cane stalk. Principle component analysis (PCA) was applied to examine the differences of spectra scanned from 180 samples including 3 types of waxy type; white, black, and mixed black and white. Seven widespread pretreatments were employed to reduce the effect of waxy types. Results show that spectra of samples with each waxy type was separated in groups and SNV pretreatment gave the best results but was not able to eliminate the effect compared to the wax-removed samples.  Meanwhile, the standard deviation of absorbance values, at the wavelength of 760, 904 and 970 nm of 3 samples, was used for assessing the repeatability and reproducibility. The samples with removing waxy cover provided lower the standard deviation of absorbance values of spectra than the best pretreated spectra using standard normal variate (SNV) of the samples without removing waxy cover by one to six times. Thus, the waxy material on cane surface should be removed before collect spectra

Peg-tooth spacing and guide vane inclination of a Thai combine harvester affecting harvesting losses

Peg-tooth spacing and guide vane inclination of Thai combine harvesters are important parameters affecting harvesting losses. The harvester owners often adjust the peg-tooth spacing and guide vane inclination before harvesting. This study aimed to evaluate how harvesting loss are affected by the peg-tooth spacing and guide vane inclination of a Thai combine harvester. The results showed that increasing of peg-tooth spacing resulted in linearly increasing threshing unit loss. Threshing unit losses of Khao Dok Mali 105 (KDML 105) and Chainat 1 rice varieties were 0.0045 and 0.0306%/mm of spacing, respectively. Increasing of the guide vane inclination resulted in a linearly decreasing threshing unit loss. Threshing unit losses of KDML 105 and Chainat 1 rice varieties were 0.0575 and 0.3112%/degree of the guide vane, respectively

Strain gauge basedsensor for real-time truck freightmonitoring

This study aims to develop a weight monitoring sensor for trucks used in sugarcane harvesting. Finite element simulation of the behavior of the load of harvested sugarcane in the bin acting on the truck chassis was established. The position of the weight sensors was determined based on the stress distribution results. The weight sensors were then designed and constructed. A testing unit representing the truck chassis was constructed for calibration of the weight sensors. The results showed that sensors should be installed on the chassis at 180 mm above the rear wheel mounting position, where the maximum stress was 7.64 MPa. The designed weight sensor consisted of four strain gauges attached to the end of two 30 mm diameter bolts. All strain gauges were wired into a Wheatstone bridge circuit (full bridge). A linear relationship between the signals from the sensor and weight was found for weights greater than 1000 N. The weight of sugarcane can be monitored during harvest to do yield mapping and support the combine while it harvests the field

Analysis of discharge consistency and performance of a sugarcane billet planter with side-conveyer concept

Sugarcane is an important economic crop of Okinawa Prefecture. The sugarcane billet planter has been widely used in Okinawa due to high labor costs and planting time limits. Most of them were powered by hydraulic systems to avoid ground wheel drive problems when working under high moisture heavy clay conditions. This study aimed to evaluate the performance and discharge consistency of the sugarcane billet planter, YABIKU B600, operated in Minami Daito Island, Okinawa Prefecture. The Ni28 cultivar seed cane was harvested and chopped to an average length of 21.8 cm by Austoft TM2008 harvester. The field experiment was done with 3 replications. A video camera with GPS logger was positioned over the hopper of the planter during the tests to examine the performance and planting consistency of the planter. The numbers of discharged billets at each frame were recorded to calculate the discharge index or planting rate. Moreover, the speed, GPS position and time of each activity were collected to obtain the field capacity and field efficiency of the planter. The results showed that the average traveling speed of the planter was 0.97 m/s. The field capacity was 0.24 ha/hr with a field efficiency of 45.66%. The average discharge index was 7.2 billet/m. Considering a discharge index range of 8-10 billet/m, the precision index averaged 24.63%

Relationships between nutrients and sucrose concentrations in sugarcane juice and use of juice analysis for nutrient diagnosis in Japan

Sugarcane is an important economic crop in southwest Japan, but its production is decreasing. To increase sugar production, both sugarcane yield and quality should be improved. Fertilizer management is one of the factors that influence sugarcane quality. We accordingly focused on nutrients present in sugarcane juice and attempted to identify the key factors affecting sugarcane quality. We collected sugarcane samples from 2013 to 2015 from all of the sugar mills in Japan and examined the relationships between juice nutrients and sucrose concentration. Juice analysis over 3 year showed that potassium (K+) and chloride (Cl−) were the most abundant cation and anion in the juice and that both negatively correlated with the sucrose concentration. K+ and Cl− concentrations significantly varied depending on production areas and those with higher K+ and Cl− concentrations had a low sucrose concentration. This finding suggests that sugarcane in those areas may have been supplied with these two ions in excess. Electrical conductivity (EC) in the juice always positively correlated with K+ and Cl− concentrations. EC may thus be a reliable indicator of K+ and Cl− concentrations and could be used for nutrient diagnosis because of its ease of measurement. For improving sugarcane quality, we recommend that potassium chloride, which supplies both K+ and Cl− and is a commonly used potassium fertilizer for sugarcane production in Japan, should be used in lower quantities in a year following one in which the EC of sugarcane juice at harvest is found to be high

A portable near infrared spectrometer as a non-destructive tool for rapid screening of solid density stalk in a sugarcane breeding program

The aim of this study is to estimate the solid density of cane stalk using the short-wave near infrared spectroscopy across mobile near infrared spectrometer with the wavelength of 570–1031 nm. The idea was to follow up the change of individual sugarcane stalk weight using non-destructive method, then the knowledge of solid density was required. The sugarcane stalk weight could be calculated by multiplication between solid density and its volume, which could be calculated from cane stalk diameters and its length 40 cm.The model was optimized using PLS regression. To get the effective model, the effect of waxy cover, different integration time, different wavelength range, and various pre-processing technique were considered. The result showed that original sample model gave poor performance because of the effect of waxy cover. Meanwhile, NIR spectra without waxy cover model provided a good performance. The best model was achieved where the NIR spectra scanned with integration time of 200 ms, wavelength of 700–1000 nm, and with smoothing moving average were applied. The standard error of prediction (SEP), relative standard error of prediction (RSEP) were 22.131 kg/m3 and 2.000%, respectively. It could be applied for screening. Hence the outcome showed that NIR spectroscopy could be used as a non-destructive technique to follow up the mass change of individual cane stalk. For cane breeding and mass yield programs, the knowledge could be used to estimate the growing rate when the environmental condition was changed. The model would benefit to breeding with time and cost consumption reduction. Keywords: Sugarcane stalk, Solid density, Non-destructive, Short-wave near infrared spectroscop

Report of research activities and achievements

バイオシステム工学分野では，農業機械学，農業情報工学，農産施設工学を基礎とする講義科目を提供している．亜熱帯島嶼環境に適した機械化と情報化を核とする高度農業生産技術，バイオマス利用技術，農産物などの加工・高付加価値化技術の研究開発を行っており，近年は，スマート農業やスマート・フードチェーンシステムとして注目されている