Effects of Mechanical Harvesting on Sugarcane Stubble Quality and Growth of Ratoon

The experiment was conducted with the traditional manual harvesting and mechanical harvesting of sugarcane,to compare the effects of different harvesting method on the sugarcane stubble quality and the growth of ratoon.The experimental results are as follows.(i) The stubble height and breaking stubble rate of mechanical harvesting was significantly higher than manual harvesting,the stubble height of lodging species and difficult defoliation species increased in mechanical harvesting condition.Varieties with higher levels of fiber had lower rate of broken stubble.(ii) The effects of mechanical harvesting on germination of next year ratoon were quite different due to different varieties,indicating that the better perennial species have less impact than the poor perennial species.(iii) Compared with manual harvesting,mechanical harvesting had slightly higher plant height and single-stem weight and less effective stems number,the difference of cane yield was not significant,but sucrose content increased 0.53%.(iv) Mechanical harvesting combining with leaves crushing could reduce the impact on the germination of ratoon,improve the single-stem weight and increase the effective number of stems.

The underlying mechanism of variety–water–nitrogen–stubble damage interactions on yield formation in ratoon rice with low stubble height under mechanized harvesting

Agronomic measures are the key to promote the sustainable development of ratoon rice by reducing the damage from mechanical crushing to the residual stubble of the main crop, thereby mitigating the impact on axillary bud sprouting and yield formation in ratoon rice. This study used widely recommended conventional rice Jiafuzhan and hybrid rice Yongyou 2640 as the test materials to conduct a four-factor block design field experiment in a greenhouse of the experimental farm of Fujian Agricultural and Forestry University, China from 2018 to 2019.The treatments included fertilization and no fertilization, alternate wetting and drying irrigation and continuous water flooding irrigation, and plots with and without artificial crushing damage on the rice stubble. At the same time, a 13C stable isotope in-situ detection technology was used to fertilize the pot experiment. The results showed significant interactions among varieties, water management, nitrogen application and stubble status.Relative to the long-term water flooding treatment, the treatment with sequential application of nitrogen fertilizer coupled with moderate field drought for root-vigor and tiller promotion before and after harvesting of the main crop, significantly improved the effective tillers from low position nodes. This in turn increased the effective panicles per plant and grains per panicle by reducing the influence of artificial crushing damage on rice stubble and achieving a high yield of the regenerated rice. Furthermore, the partitioning of 13C assimilates to the residual stubble and its axillary buds were significantly improved at the mature stage of the main crop, while the translocation rate to roots and rhizosphere soil was reduced at the later growth stage of ratooning season rice. This was triggered by the metabolism of hormones and polyamines at the stem base regulated by the interaction of water and fertilizer at this time. We therefore suggest that to achieve a high yield of ratoon rice with low stubble height under mechanized harvesting, the timely application of nitrogen fertilizer is fundamental,coupled with moderate field drying for root-vigor preservation and tiller promotion before and after the mechanical harvesting of the main crop.

Design and evaluation of a two-section canopy shaker with variable frequency for mechanical harvesting of citrus

Canopy shaking is one of the most commonly used techniques for mechanical harvesting of citrus fruits in orange juice industry.However,tree damage and low harvesting efficiency are the top concerns of growers in adopting the existing harvesting equipment on a large scale.The purpose of this research was to develop a novel canopy shaking system to minimize tree damage and maximize fruit removal for mechanical citrus harvesting.In this study,a two-section canopy shaker composing of top and bottom shaking systems mounted on two rotating drums was proposed and developed.It was configured with two sets of flexible bow-shaped shaking rods in a staggered distribution,which can shake the top and bottom zones of the tree canopy independently.The shaking system was designed based on a linked crank-rocker mechanism.Kinematic simulation analysis was conducted to verify the quick return characteristics and differential properties of this mechanism.Vibration test showed that the frequency of the shaking rod could be adjusted within a range of 1.1-8.8 Hz related to hydraulic motor speeds.The field tests of the shaking system with an average frequency of 4.7 Hz achieved a fruit removal percentage of 82.6%and tree damage rate of 5.4%under a tractor speed of 3 km/h.By contrast,the combined shaking frequency of 4.7 Hz&4.1 Hz of the canopy shaker produced less tree damage with a percentage of 3.9%.This study indicated that the two-section canopy shaker with an optimized frequency combination could be adaptable to the different zones of the tree canopy,and obtain lower tree damage and higher fruit removal percentage.

Design and Analysis of a Mechanical Device to Harvest Energy from Human Footstep Motion

Portable electronics is usually powered by battery,which is not sustainable not only to the longtime outdoor use but also to our living environment.There is rich kinetic energy in footstep motion during walking,so it is ideal to harvest the kinetic energy from human footstep motion as power source for portable electronic devices.In this paper,a novel mechanism based on dual-oscillating mode is designed to harvest the kinetic energy from footstep motion.The harvester contains two oscillating sub-mechanisms：one is spring-mass oscillator to absorb the vibration from external excitation,i.e.,the footstep motion,and the other is cantilever beam with tip mass for amplifying the vibration.Theoretic analysis shows that the dual-oscillating mechanism can be more effectively harness the foot step motion.The energy conversion sub-mechanism is based on the electromagnetic induction,where the wire coils fixed at the tip end of the cantilever beam serves as the slider and permanent magnets and yoke form the changing magnetic field.Simulation shows that the harvester,with total mass 70 g,can produce about 100 mW of electricity at the walking speed of 2 steps per second.

Comparison and analysis of maize grain commodity quality and mechanical harvest quality between China and the United States

Maize is a bulk commodity in international agricultural product trading,and unified and standardized quality inspection standards are the basis of purchase and sales and other trading behaviors.China and the United States are the largest maize producers and consumers in the world,jointly accounting for more than 60%of the world's total production.In this research,the used data were from annual maize harvest quality reports released by the U.S.Grains Council in 2011-2019 and 2987 groups of mechanical grain harvest sample data collected by the Crop Cultivation and Physiology Innovation Team of the Chinese Academy of Agricultural Sciences in 2012-2019,this study compares the quality standards of commercial maize grain in China and the United States,the mechanical harvest quality(which affects the quality of the maize grain commodity),and the status quo of harvesting and storage processes in the two countries.Additionally,this study analyzes the differences in the formulation of mechanical harvest quality standards between China and the United States,as well as the reasons behind these differences,and recommends requirements for the formulation of quality standards for maize production technology and commodities that are in line with the economic conditions and maize-production conditions in China and in line with international standards in order to provide support for the industrialization of modern maize production in China.

Piezoionics:Mechanical-to-ionic transduction for sensing,biointerface,and energy harvesting

Piezoionic materials consisting of a polymer matrix and mobile ions can produce an electrical output upon an applied pressure inducing an ion concentration gradient.Distinct from charges generated by the piezoelectric or triboelectric effects,the use of generated mobile ions to carry a signal closely resembles many ionic biological processes.Due to this similarity to biology,the piezoionic effect has great potential to enable seamless integration with biological systems,which accelerates the advancement of medical devices and personalized medicine.In this review,a comprehensive description of the piezoionic mechanism,methods,and applications are presented,with the aim to facilitate a dialogue among relevant scientific communities.First,the piezoionic effect is briefly introduced,then the development of mechanistic understanding over time is surveyed.Next,different types of piezoionic materials are reviewed and methods to enhance the piezoionic output via materials properties,electrode interfaces,and device architectures are detailed.Finally,applications,challenges,and outlooks are provided.With its novel properties,piezoionics is expected to play a key role in the overcoming of grand challenges in the areas of sensing,biointerfaces,and energy harvesting.

Visible Losses in Mechanized Harvesting of Sugarcane Using the Case IH A4000 Harvester

Sugarcane is a major Brazilian agricultural product. The area cultivated in the state of Rio de Janeiro for the 2011-12 crop was of 41.31 thousand hectares. The process of mechanized harvesting of the crop still has many visible losses of raw materials caused by several factors. This study aimed at evaluating the visible losses of sugarcane and ratoon damage using the Case A4000 harvester and was conducted in the municipality of Campos dos Goytacazes, in the state of Rio de Janeiro, Brazil. The materials left on the field by the harvester were collected in six ratoon cane rows, with a length of 350 m, setting the frame sampling to every 50 m. The sampling area consisted of 20 m2, with eight repetitions. The losses were calculated in t&middotha-1 and in %. The comparison of averages was performed by using the confidence interval, constructed by statistical “t” at 5% probability to compare the types of losses. The estimated productivity of the area was of 54 t&middotha-1. The differences between the types of losses were significant. The billets and splinters were found in greater quantity.

Flexible multilayer MEMS coils and their application in energy harvesters

Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable electronics.Conventional electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power density.In this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic harvester.The core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring structures.The wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the devices.The output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural parameters.The results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.Flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex surfaces.After the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 Hz with a resistor of 3.5 kΩinternal resistance.Moreover,a 470μF capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb continuously.This strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.

Dynamic characteristics of dwarf Chinese hickory trees under impact excitations for mechanical fruit harvesting

Mechanical vibration is an effective fruit harvesting method.To evaluate the dynamic characteristics of dwarf Chinese hickory(Carya cathayensis Sarg.)trees and the influence of the tree structure on transmission and attenuation of dynamic response,a new method was proposed based on acceleration admittance measurement on dwarf Chinese hickory trees in orchard environment under impact excitation.The primary resonance frequencies of the tree can be determined based on the acceleration admittance measurement.The effect of the tree structure on the vibratory transmission was quantified using the attenuation ratio of the acceleration admittance.A 5-year-old dwarf Chinese hickory tree sample was tested.The responses at three resonance frequencies(5,9 and 12 Hz)were analyzed because they were identified as the most effective bands of excitation for the main part of the tree specimen.The results reveal that the variation of the dynamic response along the testing tree is greatly related to the Chinese hickory tree structure.The attenuation ratio of the acceleration admittance at the branch crotches indicates the leader top crotch may amplify the acceleration admittance no matter what the crotch angle and the branch diameter is.Unlike the crotches,the branch chain nodes generally have negative influence on the acceleration admittance along the branch chains which heavily depend on the branch chain configuration.The branch chains with a chain angle no less than 150°and a wood diameter ratio close to 1.0 could produce little influence on the vibration transmission.For those branches with chain angle less than 150°,the vibration was generally attenuated at their chain nodes at three resonance frequencies.To impose impact excitations on the tree,high mechanical harvesting efficiency could be achieved on those branch chains which are almost straight and uniform.

Heavy soil drying during mid-to-late grain filling stage of the main crop to reduce yield loss of the ratoon crop in a mechanized rice ratooning system

Yield loss(Y_(Loss)) in the ratoon crop due to crushing damage to left stubble from mechanical harvesting of the main crop is a constraint for wide adoption of mechanized rice ratooning technology.Soil drying before the harvest of the main crop has been proposed to overcome this problem.The objective of this study was to determine the effect of soil drying during the mid-to-late grain filling stage of the main crop on grain yield of the ratoon crop in a mechanized rice ratooning system.Field experiments were conducted to compare Y_(Loss) between light(LD) and heavy(HD) soil drying treatments in Hubei province,central China in 2017 and 2018.Y_(Loss) was calculated as the percentage of yield reduction in the ratoon crop with the main crop harvested mechanically,relative to the grain yield of the ratoon crop with the main crop harvested manually.In comparison with LD,soil hardness was increased by 42.8%-84.7% in HD at the 5-20 cm soil depth at maturity of the main crop.Soil hardness at 5 and 10 cm depths reached respectively 4.05 and 7.07 kg cm^(-2) in HD.Soil drying treatment did not significantly affect the grain yield of the main crop.Under mechanical harvesting of the main crop,HD increased the grain yield of the ratoon crop by 9.4% relative to LD.Consequently,Y_(Loss) was only 3.4% in HD,in contrast to 16.3% in LD.The differences in grain yield and Y_(Loos) between the two soil drying treatments were explained mainly by panicles m^(-2),which was increased significantly by HD in the track zone of the ratoon crop compared with LD.These results suggest that heavy soil drying practice during the mid-to-late grain filling stage of the main crop is effective for reducing Y_(Loss) of the ratoon crop in a mechanized rice ratooning system.

In-field harvest loss of mechanically-harvested maize grain and affecting factors in China

Field harvest loss is a common problem of maize grain mechanical harvesting in China and abroad.From 2012 to 2019,2987 groups of samples for the quality of mechanical grain harvesting in field were obtained in 21 major maize-producing provinces,cities,and regions of China.The analysis performed in this study showed that the average harvest loss of fallen ears was equivalent to 76.5%of the total harvest loss,indicating that the harvest loss in the mechanical harvesting of maize grain mainly came from the loss of fallen ears.Meanwhile,statistical analysis of the harvest loss in different ranges of grain moisture contents showed that,when the grain moisture content fell below 20%,the harvest loss rate of fallen ears and the total harvest loss rate both increased sharply,and the harvest loss of fallen ears increased faster than the harvest loss of fallen grain with a decreasing grain moisture content.Moreover,the results of multi-point experiments and harvest experiments in different periods showed that,during harvesting time,the harvest loss of fallen ears caused by lodging was the main reason for in-field harvest losses in the mechanical harvesting of maize grain.Apart from the above mentioned,the test results of 35 groups of harvesters for the in-field mechanical harvesting of maize grain showed that the harvester types and their operating parameters were important factors affecting the harvest loss in the mechanical harvesting of maize grain.Therefore,the principal paths to reduce harvest loss in the mechanical harvesting of maize grain are to breed lodging-resistant maize varieties,adopt reasonable planting densities,cultivate healthy plants,develop harvesters with low harvesting loss,intensify the training of operators,and harvest at an appropriate time.

Evaluation of grain breakage sensitivity of maize varieties mechanically-harvested by combine harvester

A high grain breakage rate is the main problem that occurs during mechanical maize harvest in China.The breakage sensitivity of different varieties was significantly different,and the breakage resistance is heritable.Therefore,breakage resistant variety screening can help improve the field production efficiency and provide references for breeding work.In this study,42 varieties of maize were harvested with the same mechanical parameters and the same manipulator on a range of harvest dates at experimental stations in Xinxiang,Henan Province,in 2017 and Changji,Xinjiang Province,in 2018 to determine the sensitivity of grain moisture content on grain breakage rate during machine harvest for different varieties.The integral value of the grain breakage rate curve corresponding to the range of 15%to 30%grain moisture content was used as an index that expressed the sensitivity of maize grains to breakage depending on grain moisture content(BSW).Forty-two varieties were categorized as having weak,intermediate,or strong BSW.Among the same four varieties in the two stations,Lianchuang 825 and Lianchuang 808 were classified as sensitive and fragile varieties,Shandan 650 was classified as an intermediate variety,Zeyu 8911 was divided into weak sensitive and breakage-resistance varieties in Xinxiang and intermediate varieties in Changji.The BSW classification results at the two experimental sites were generally consistent,indicating that breakage sensitivity due to moisture content may be a relatively stable genetic characteristic.This study suggested that the integral method for determining BSW can be used to assess the resistance of different maize varieties to grain breakage during mechanical harvesting.The integral method was used to identify twelve breakage-resistant varieties in Xinxiang Station,and six breakage-resistant varieties in Changji Station.This study provides a method for screening maize varieties that are suited to mechanical grain harvesting and for studying the mechanisms of grain breakage resistance.

Grain dehydration rate is related to post-silking thermal time and ear characters in different maize hybrids

Mechanized grain harvest of maize becomes increasingly important with growing land plot size in Northeast China. Grain moisture is an important factor affecting the performance of mechanized grain harvest. However, it remains unclear what influences grain dehydration rate. In this study, maize grain dehydrating process was investigated in a two-year field experiment with five hybrids under two planting densities in 2017 and 2018. It was found that damaged-grain ratio was the main factor affecting mechanized harvest quality, and this ratio was positively correlated with grain moisture content at harvest(R^(2)=0.6372, P<0.01). To fulfill the national standard of <5% damaged-grain ratio for mechanized grain harvest, the optimal maize grain moisture content was 22.3%. From silking to physiological maturity, grain dehydrating process was mostly dependent on the thermal time(growing degree days, GDDs)(r=-0.9412, P<0.01). The average grain moisture content at physiological maturity was 29.4%. Thereafter, the linear relationship between GDDs and grain moisture still existed, but the correlation coefficient became smaller(r=-0.8267, P<0.01). At this stage, grain dehydrating process was greatly affected by genotypes. Grain dehydrated faster when a hybrid has a smaller husk area(r=0.6591, P<0.05), larger ear angle(r=-0.7582, P<0.05), longer ear peduncle(r=-0.9356, P<0.01) and finer ear(r=0.9369, P<0.01). These parameters can be used for breeders and farmers to select hybrids suitable for mechanized grain harvest.

Allocation of maize varieties according to temperature for use in mechanical kernel harvesting in Ningxia, China

The reasonable assessment of maize varieties in different ecological regions can allow temperature resources to be fully exploited and reach the goal of high yield and efficiency and is thus an important direction of modern maize development in China.In this study,a logistic power nonlinear growth model was used to simulate the accumulated temperature required for kernel dehydration to moisture contents of 25%,20%,and 16%for various maize cultivar,which were divided into six types based on the accumulated temperature required for kernel dehydration to a moisture content of 25%.The relationship between the yield of maize cultivars and the accumulated temperature required for kernel dehydration to a moisture content of 25%was found to follow a unary function model.Changing the planted maize variety was found to increase economic returns by more than 7000 RMB/hm2 in Ningxia,Northwest China.Under the conditions of mechanical grain harvesting,economic benefits can be further increased by means of selecting high yields and fast-dehydrating varieties,selling when the grain dehydration is below 16%.A better way to achieve grain dehydration to a moisture content below 16%is to postpone the harvest date as much as possible rather than drying after the harvest at physiological maturity.The areas of various types of maize varieties can be dehydrated to moisture contents of 25%,20%,and 16%were marked.Based on the distribution of heat resources in different regions of Ningxia from the normal sowing date to October 31 before winter irrigation,the appropriate cultivars for various regions in the province were determined based on production benefits.Therefore,in different areas of Ningxia,selecting suitable maize varieties according to temperature resources can reach a high yield and mechanical kernel harvesting,and ultimately obtain higher economic benefits.

Recent progress and future prospects for mechanized harvesting of fruit crops with shaking systems

Mechanized harvesting technologies with shaking systems for fruit industry have been widely investigated and significantly developed over the past several decades which were presented by a large amount of literature.This paper reviews the research and development progress of mechanized harvesting of fruits systematically with a focus on the theoretical study,fruit crop variety,shaking system categories,abscission chemical agents,and their actual applications.Based on the comprehensive review,mechanized harvesting systems for different fruit crops appear multifarious shaking modes with various vibratory mechanisms and structural dimensions.Major advantages in the development of fruit mechanical harvesting with effective vibratory patterns and catching frames provide a series of economic and agronomic benefits,such as reducing labor costs,promoting standardized planting,and increasing productivity.However,fruit injury and tree damage are the main reasons why mechanical shaking systems are rarely used for fresh fruit harvesting because of tenderness and frangibility of the fruit crops.Therefore,more efforts should be concentrated on the innovative shake-and-catch system with suitable frequency and amplitude to achieve low fruit damage or even nondestructive harvesting for fresh fruit market.This overview summarized the advantages and bottlenecks of these shaking systems for fruit harvesting and proposed the challenges and some constructive prospective viewpoints aimed at the major issues of mechanical harvesting techniques.In addition,employing sorting technologies to classify the postharvest fruits provide a new direction for the further development of mechanized harvesting in high-value fruit crops,as well as bring more benefits to growers and increase their interest in equipment investment on the mechanical shaking harvester for the fruit industry.

Performance evaluation of lateral canopy shakers with catch frame for continuous harvesting of oranges for juice industry

Citrus is mainly oriented to fresh consumption,and harvesting is usually performed manually.However,the high cost of harvesting and the low availability of labour can compromise the profitability of the crop when it is destined to juice industry.The development of citrus mechanical harvesting for industrial processing is conditioned to reach a high fruit removal efficiency,with a reduced damage to both fruit and trees.The current machines available are very large,requiring extensive plantations with long rows of trees to be efficient.In this study,two lateral canopy shakers equipped with a catch frame were evaluated to harvest independently both sides of the hedge on intensive citrus plantations with the main objective of determining their performance and feasibility.The lateral canopy shakers tested were three tractor-drawn machines,one commercial machine and two prototypes.The tested machines reached a mean value of 78%of fruit removal.Besides,the prototypes,equipped with a catch frame,were able to recover a mean value of 70%of yield.Although the results were promising,for achieving an efficient result,the application of this harvesting technology still requires a process of improvement,and the adaptation of both the machine and the plantation.The machines should reduce the amount of post-harvest ground fruit(5.9%-10.4%).Tree damages generated by the contact of the catch frame with the trunk and the metal rods with main branches were the most relevant.Therefore,it is still necessary to increase the ground speed of the machinery and improving the design of the rods,regulating the rod penetrating deep in the canopy to improve the fruit recovery and limit the damage caused to the trees.

OsGRF4 controls grain shape, panicle length and seed shattering in rice

Traits such as grain shape, panicle length and seed shattering, play important roles in grain yield and harvest. In this study, the cloning and functional analysis of PANICLE TRAITS 2 （PT2）, a novel gene from the Indica rice Chuandali （CDL）, is reported. PT2 is synonymous with Growth-Regulating Factor 4 （OsGRF4）, which encodes a growth-regulating factor that positively regulates grain shape and panicle length and negatively regulates seed shattering. Higher expression of OsGRF4 is correlated with larger grain, longer panicle and lower seed shattering. A unique OsGRF4 mutation, which occurs at the OsmiRNA396 target site of OsGRF4, seems to be associated with high levels of OsGRF4 expression, and results in phenotypic difference. Further research showed that OsGRF4 regulated two cytokinin dehydrogenase precursor genes （CKX5 and CKX1） resulting in increased cytokinin levels, which might affect the panicle traits. High storage capacity and moderate seed shattering of OsGRF4 may be useful in high-yield breeding and mechanized harvesting of rice. Our findings provide additional insight into the molecular basis of panicle growth.

Recent progress on flexible nanogenerators toward self-powered systems

The advances in wearable/flexible electronics have triggered tremendous demands for flexible power sources,where flexible nanogenerators,capable of converting mechanical energy into electricity,demonstrate its great potential.Here,recent progress on flexible nanogenerators for mechanical energy harvesting toward self-powered systems,including flexible piezoelectric and triboelectric nanogenerator,is reviewed.The emphasis is mainly on the basic working principle,the newly developed materials and structural design as well as associated typical applications for energy harvesting,sensing,and selfpowered systems.In addition,the progress of flexible hybrid nanogenerator in terms of its applications is also highlighted.Finally,the challenges and future perspectives toward flexible self-powered systems are reviewed.