Experiment and analysis of potato-soil separation based on impact recording technology

In order to discover the damage mechanism and improve separation performance in the separation process of potato-soil mixture,the experiment was conducted on an in-house test-bed.The impact recording device and high-speed camera technology were employed in order to obtain the instantaneous dynamics of the potato-soil mixture for detail data analysis.Five vibration intensities were defined according to the vibration frequency and amplitude.It was found that the mean number of impacts and maximum impact acceleration increased significantly as the level of vibration intensity rose.As a result,the separation performance increased significantly,however,the bruising rate also increased to a certain extent.The mathematical relationship between the maximum impact acceleration and the factors of interest,including vibration amplitude,the vibration frequency and the operating speed of the separation sieves was established through the response surface experiment.It was demonstrated that the presented model was capable to reflect the degree of the factors on influencing bruising rate and separation performance.According to the significance on the maximum impact acceleration,the factors of interest were given in a descending order with vibration frequency,vibration amplitude,running speed of the separation sieve.A set of the optimum operating parameters were found to achieve a desired separation performance as follows,the vibration amplitude was 34.1 mm,the vibration frequency was 5.24 Hz,the running speed of the separation sieve was 2.05 m/s;where the maximum impact acceleration was 98.62 g,the relative error was 3.23%,the bruising rate was 1.81%and the separation performance was 98.5%.The presented model can potentially provide a technical reference for further investigation of the separation mechanism and development of measures for reducing the loss of separation.

Effects of mechanical operation-induced root injury on maize growth and yield

A 2-year field experiment was conducted in 2015 and 2016 by using artificial root pruning to simulate mechanical root injury caused by agricultural machinery components and reveal its effects on maize growth and yield.Quasi-level orthogonal experimental design was employed to create orthogonal tables with four factors of interest,namely,pruning time(jointing stage,JS;big trumpet period,BTP),pruning method(unilateral pruning,UNP;bilateral pruning,BIP),pruning distance(5,10,and 15 cm)and pruning depth(5,10,and 15 cm).Results revealed that (1)maize growth was inhibited at the beginning of root pruning;(2)stem diameter(SD)and plant height(PHE)were smaller than those of the control check(CK)but exceeded the latter after 20 d of root pruning in JS;(3)SD and PHE were always smaller than those of the CK under root pruning in BTP;(4)T8(BTP,BIP,5 cm of pruning distance and 15 cm of pruning depth)can reach to a significant level(p<0.01).The vertical distribution and total dry weight(TDW)of maize roots in soil were affected by different root pruning treatments.When pruning in JS,the root ratio in 0-10 cm soil was 11.6%in T2(JS,UNP,a pruning distance of 10 cm and pruning depth of 10 cm).When pruning in BTP,the root ratio of 10-20 cm soil layer increased by 15%.However,the TDW of maize decreased,the largest of which occurred in T8 at 53%.With the exception of a 0.43%increase in T3(JS,UNP,15 cm of pruning distance and 15 cm of pruning depth),the maize yield of all other treatments decreased compared with that of CK,and the largest reduction was in T8 at up to 19.1%.This finding suggests that a small pruning distance and a large pruning depth greatly influence the growth and yield of maize before and during pruning in BTP.The influence of BIP is greater than that of UNP.These results provide evidence for the effects of mechanical root injury on maize growth and yield and serve as a reference for the selection of mechanical topdressing parameters.