Effects of Different Planting Densities on the Yield of Rice Developed from Seedlings Dry Raised in Plug Trays

[Objectives]This study was conducted to investigate the effects of different planting densities on rice tillering dynamics and yield. [Methods]The effects of different planting densities on rice yield were studied based on seedlings dry raised in plug trays. [Results]Planting density had obvious effects on tillering dynamics,number of panicles per unit area,number of grains per panicle and rice yield under the condition of seedlings dry raised in plug trays. Comprehensive analysis showed that the row spacing × hill spacing = 25 cm × 14 cm,that is,the planting density of 2. 85 × 10~5 hills/hm^2,achieved the highest yield,at 9 960 kg/hm^2. [Conclusions]This study provides a scientific basis for optimizing rice cultivation techniques and achieving high yield and high efficiency in rice production.

Effects of plug tray cell size on the growth of Atractylodes Chinensis (DC) Koidz seedlings

Atractylodes Chinensis(DC)Koidz is a perennial herb often used as a prescription medicine for influenza,to invigorate the spleen and remove dampness.The quality of the herb is determined by the quality of the seedlings.The traditional A.chinensis seedling production technique has nonuniform seedlings and low mechanisation.The plug seedling technique was used to produce A.Chinensis seedlings.This study was conducted to determine the growth characteristics of A.Chinensis seedlings according to the cell size of plug trays and number of days after sowing.Plant height,stem diameter,rhizome diameter,number of leaves,leaf area,and shoot dry and fresh weight of A.Chinensis seedlings were significantly higher in the P32-D treatment than in the P72,P50,and P32 treatments,but not significantly different from the P28-D treatment 60 d after sowing.The P28-D treatment resulted in a considerable drop in rhizome fresh weight and healthy seedling index,both of which are key indicators for assessing seedling quality.Although the differences in Pn among treatments were not significantly different,Tr was considerably greater in A.Chinensis seedlings treated with P32-D and P28-D than in the other three treatments.The P32-D and P28-D treatments had considerably greater potential maximum photochemical efficiency of PSII,quantum yield of photosystem II,photochemical quenching and electron transport rate than the other three treatments.Root vitality of A.Chinensis seedlings was significantly stronger in the P32-D treatment than in the other four treatments,and it was 1.9 times higher than in the P28-D treatment.The soluble protein,soluble sugar,and starch contents of A.Chinensis seedlings were highest in the P32-D treatment,but the differences among treatments were not significant.LUE,EUE,PY and EY were significantly higher in the P32-D treatment than in the other four treatments,being 1.3,1.3,1.4 and 1.4 times higher than in P28-D,respectively.On the other hand,as for the change in the growth of A.Chinensis seedlings according to the number of days after sowing,the growth of shoots and rhizome was most vigorous at the 60 d after sowing,while the fresh weight of the rhizome,which can be considered as an indicator of root growth,increased steadily during the experiment but slowed down after 60 d.As a result,32-cell deepened plug trays and a seedling nursery for a period of 60-75 d are recommended for commercial cultivation of A.Chinensis seedlings.This will provide technical support for production in A.Chinensis seedling.

Effects of Low Temperature and Poor Light Environments under LED Lighting on Quality Change of Pepper Seedlings during Storage

Storage and transportation of vegetable commercial seedlings becomes an important link along with the continuous expansion of planting areas of facility vegetables and vegetable seedling culture industry. In this study,pepper variety‘Nongda 24' was as the experimental material,and changes in the morphological and physiological indicators of plug seedlings in different low temperature( 6 and 11℃) and poor light environments were studied to find suitable storage environmental conditions. The results showed that pepper seedlings could be stored and transported for 14 days when storage temperature was 11℃ and light conditions such as light intensity and photoperiod were 30 μmol/( m^2·s)and 12 h/d by using a fluorescent lamp with R∶ B ratio of 1. 9,and 15 μmol/( m^2·s) and 24 h/d by using LED with R∶ B ratio of 1. 3,respectively. Moreover,the quality of pepper seedlings could be protected effectively. Compared to the fluorescent lamp,LED with high luminous efficiency and low energy consumption was suitable for the storage or long-distance transportation of pepper seedlings in low temperature and poor light environments.

Selection of Optimal Medium for Cultivation of Idesia polycarpa var.vestita Seedlings in the Industrialized Nursery Process

Idesia polycarpa Maxim.var.vestita Diels is an important oil plant with high economic value.In order to improve seed germination and to cultivate high quality seedlings,we set out to identify an optimal medium for its seedling growth in a plastic cave tray(plug seedling).In this study,four different media including M_(1)(soil),M_(2)(peat∶perlite=2∶1),M_3(peat),and M_4(peat∶perlite∶vermiculite=2∶1∶1)were tested in industrialized plug seedlings.The seedling growth of Idesia polycarpa var.vestita including plant height,crown diameter,leaf number,ground diameter,the relative chlorophyll contents of leaves,etc.was measured.The results indicated that the medium M_(2) was the best for increasing seedling height,crown diameter,leaf counts,ground diameter,and the relative chlorophyll contents of leaves.Therefore,medium M_(2) is recommended in the industrialized nursery process for the seedling growth of Idesia polycarpa var.vestita.

Reverse design and tests of vegetable plug seedling pick-up mechanism of planetary gear train with non-circular gears

In the previous research,the seedling pick-up mechanism of the planetary gear train with incomplete eccentric circular gear and non-circular gears for vegetable plug seedlings still has two shortcomings.One is that not enough seedling pick-up depth leads to a low success ratio of seedling pick-up at high rotation speeds,the other is that the smaller seedling pushing angle results in poor seedling pushing effect.Therefore,the reverse design of the seedling pick-up mechanism based on its motion trajectory was carried out.The local trajectory of seedling pick-up and seedling pushing sections was adjusted to obtain the theoretical motion trajectory of the seedling pick-up mechanism.The cubic non-uniform B-spline curve was used to fit the adjusted trajectory.A novel seedling pick-up mechanism of the planetary gear train with non-circular gears was proposed,including three combined non-circular gears,four non-circular gears,one planetary carrier,and two seedling pick-up arms.The reverse design model of the mechanism was established.The analysis and design software of the mechanism was developed to obtain the mechanism parameters meeting design requirements.The virtual prototype of the mechanism was established and its physical prototype was manufactured.Through the virtual motion simulation and high-speed photographic kinematics bench tests of the mechanism,the kinematic model and results of reverse design of the mechanism were verified,with the kinematic performances of the mechanism prototype studied.The seedling pick-up tests of the mechanism were conducted in the laboratory.The success ratios of seedling pick-up were 94.2%,95.6% and 90.2% while the seedling pick-up efficiencies of the mechanism were 60,80 and 100 plants per minute per row,respectively.Besides,the seedling pushing effect was improved mush because of the greater seedling pushing angle.The seedling pick-up mechanism through revise design is of high value to be applied in the practical vegetable plug seedling transplanters.

Optimization design and test of rice plug seedling transplanting mechanism of planetary gear train with incomplete eccentric circular gear and non-circular gears

In order to solve the problem of the high-speed mechanized transplanting of rice plug seedlings,the design requirements of transplanting mechanism for rice plug seedlings were analyzed and a kind of rice plug seedling transplanting mechanism of planetary gear train based on the drive with incomplete eccentric circular gear and non-circular gears was designed innovatively.The laboratory kinematics was examined.The working principle of the transplanting mechanism for rice plug seedlings was studied,kinematics analysis of the transplanting mechanism was carried out and its kinematic model was set up.A human-computer interaction optimization method was used to optimize the parameters of the transplanting mechanism.The computer aided analysis and optimization software of the transplanting mechanism based on Visual Basic 6.0 was developed.Through analyzing the influence of design variables on the optimization objectives of the transplanting mechanism,a set of parameters of the transplanting mechanism which meet the requirements of transplanting trajectory and posture for transplanting rice seedlings were obtained by means of human-computer interaction.The structure of the transplanting mechanism was designed according to this set of parameters,and its virtual prototype and physical prototype were set up and manufactured,respectively.The kinematic simulation test and high-speed photography kinematic test of the transplanting mechanism were conducted to obtain its kinematic performances,such as transplanting trajectory and posture.The results of bench test,simulation analysis and theoretical analysis were almost in agreement,which verified the correctness of the theoretical model and design results of the transplanting mechanism,indicating that the optimized transplanting mechanism can satisfy the requirements of transplanting rice seedlings and be applied in the rice plug seedling transplanter.

Development of a multi-adaptive feeding device for automated plug seedling transplanter

In order to improve the adaptability of the seedling feeding devices to different plug trays for various seedlings,a multi-adaptive plug seedling feeding device for automatic field transplantation was developed.Its efficiency and adaptability have been improved using a seedling delivery device equipped with a row of end-effectors,which were provided with continuous plug seedlings by a compact seedling tray conveyor carrying out a reciprocating action.Each operation for the seedling feeding device could work automatically through a control system.Three categories of plug seedlings,cucumber,pepper and tomato seedlings were tested.The results of the performance test for the prototype demonstrated that the best performance emerged in the cucumber seedlings in 50-cell trays with the highest success rate of 88%at the feeding frequency of 6 groups/min.The lowest success rate was 73.33%for the tomato seedlings in 105-cell trays at the feeding frequency of 12 groups/min.It can be concluded that the automated feeding device developed in this study could be used for various plug seedlings as a result of its strong adaptability.

Design of flower transplanting mechanisms based on double planet carrier non-circular gear train with complete rotation kinematic pair

In view of the problems of the existing mechanisms based on 2R open-chain planetary gear train for seedling transplanting,such as the bad tracking flexibility,low positioning accuracy,and high structure design difficulties of the mechanisms based on 3R open-chain planetary gear train for seedling manipulation.In this paper,a transplanting mechanism based on the solution domain synthesis of a 3R open-chain-based complete rotation kinematic pair,a gear train with a single cycle integral rotating pair,is designed.The Burmester curve equation is derived from the given transplanting trajectory and four exact poses corresponding to each other on the rotation center.Then,the open-chain road model of the 3R complete rotation kinematic pair is obtained under the constraint governed by the judgment condition of the hinge integral rotating pair.Meanwhile,combined with our developed in-house optimization software,the solution to the optimal parameters for the transplanting mechanism can be optimized according to the target trajectory.Finally,the feasibility of the design method is verified by transplanting testing,where kale seedlings with ages of about 20 d and heights of about 80-120 mm are used.The experimental results show that the actual motion trajectory of the prototype is basically identical to the theoretical trajectory,validating the feasibility of transplanting mechanism design,parts processing,and test-bed construction.Through the statistical analysis,the average success rate of transplanting is 90.625%,and the reliability of designed mechanism is satisfied.This study provides a promising solution for the seedling transplanting of two-planet scaffold pots.

Design and experiment of double planet carrier planetary gear flower transplanting mechanism

At present,there is a lack of miniaturized and highly reliable plug seedling transplanting mechanism in flowerpots planting operation,in order to meet the needs of large displacement and high vertical uprightness for flower transplanting,the paper combined the transmission characteristics of the non-circular gear planetary gear train with the swing flexibility of the cam gear and proposed a double planet carrier planetary gear transplanting mechanism.The linkage of the mechanism performs variable speed rotation relative to the first planet carrier,the linkage serves as the second planet carrier,and the transplanting arm performs variable speed swing relative to the linkage.A mathematical model of a single planetary carrier mechanism was first established using the method of open linkage group solution domain synthesis,then established the kinematic equations of the second planet carrier and the transplanting arm.The two parts are combined to form the mathematical solution model of the proposed mechanism.The initial trajectory was planned according to the trajectory requirements of seedlings planting operation,the non-circular gear pitch curve in the first planet carrier was obtained and the length of the first planet carrier is 120 mm.Then using the key points’angular deviation between the initial trajectory and the improved trajectory to obtain the cam parameters which driving the transplant arm,consequently determined the length of the second planet carrier is 69.25 mm and the length of the transplant arm is 112.4 mm.Finally,the prototype of the mechanism was manufactured,and the test verified the correctness of the design method of the double planet carrier planetary gear flower potting transplanting mechanism.The transplanting success rate of this mechanism reached 94.43%,and the plug seedlings planted in flowerpots had high uprightness.This research can provide a reference for the automatic development of research on flower transplanting machines.

Design and testing of the mechanical picking function of a high-speed seedling auto-transplanter

To improve the low transplanting efficiencies and simplify the complex structures of current automatic transplanters,a mechanical high-speed transplanter for picking plug seedlings that is suitable for planting on plastic filmswas designed.Themain components were an automatic seedling picking systemand a basket-type planting system,whichwere used for the following processes:automatic picking,planting,soil covering,and suppression of plug seedlings.The performance test was performed on the automatic transplanter with 60-day-old pepper seedlings.The transplanting efficiency was tested at speeds of 40,60,90,and 120 plants·min−1.The results showed that the coefficient of variation(CV)of the plant spacing and the missed transplanting rate increased with the planting frequency,whereas the qualified rate of planting perpendicularity and the qualified rate of planting decreasedwith the increase in the planting frequency.All planting indicesmet the JB/T 102912013 standards.The results of this study showed that the auto-transplanter could performhigh-speed transplanting on the basis of completing the following functions:automatic picking,planting,soil covering,and suppression of plug seedlings.