Correlation Analysis between Well-cellar Early Transplanting of Robust Seedlings and Diseases in Shiyan Tobacco-growing Area

[Objectives]The paper was to investigate the relationship between the well-cellar early transplanting of robust seedlings and the prevalence of diseases in the Shiyan tobacco-growing area.[Methods]The relationship between disease occurrence and meteorological factors during the field growth period was examined by analyzing the prevalence of flue-cured tobacco virus diseases,brown spot,and total disease in the Shiyan tobacco-growing area before(2013-2017)and after(2018-2022)the well-cellar early transplanting of robust tobacco seedlings.[Results]The implementation of a well-cellar early transplanting technique of robust seedlings resulted in a reduction in the average incidence of tobacco virus disease,brown spot,and total disease by 0.83%,8.85%,and 7.91%,respectively,in comparison to the incidence observed prior to early transplanting.These findings suggest that early transplanting can significantly reduce the incidence of flue-cured tobacco diseases.Prior to the well-cellar early transplanting of robust tobacco seedlings,there was a significant(including highly significant)positive correlation between the incidence of brown spot and total disease and precipitation in August and September.The incidence of brown spot and total disease in tobacco plants was found to be significantly positively correlated with May precipitation and significantly negatively correlated with May sunshine hours following the well-cellar early transplanting of robust seedlings.The advancement of the transplanting period by 20 d resulted in a reduction in the growing period of tobacco plants in the field under autumn rains(late August to November)in western China.This effectively circumvented the suitable conditions for disease occurrence and can reduce the incidence of disease.[Conclusions]This study offers a framework for enhancing the quality and efficiency of flue-cured tobacco production in the northwest tobacco-growing area of Hubei.

Study on a Bowl-based Mechanism for Transplanting Potted Strawberry Seedlings

To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.

No-tillage effects on grain yield and nitrogen requirements in hybrid rice transplanted with single seedlings: Results of a long-term experiment

This study was conducted to determine whether,and if so how,the grain yield and nitrogen(N) requirements of hybrid rice transplanted as single seedlings are affected by no-tillage(NT) practices.A fixed field experiment was done at the Experimental Farm of Hunan Agricultural University in Changsha,Hunan Province,China,from 2004 to 2014.Grain yield and yield attributes(panicle number per m2,spikelet number per panicle,spikelet filling percentage,grain weight,total biomass,and harvest index) were evaluated as well as the N-use characteristics(total N uptake,internal N-use efficiency,and N requirements) of hybrid rice transplanted as single seedlings comparing NT with conventional tillage(CT).A significant finding was that there were no significant differences in grain yield,yield attributes,and N-use characteristics between CT and NT.Averaged across the 11 years,grain yield and N requirements were 9.51 t ha^(-1) and 20.2 kg t^(-1) under CT and 9.33 t ha^(-1) and 20.0 kg t^(-1) under NT,respectively.There were significant yearly variations in grain yield,yield attributes,and N-use characteristics observed under both CT and NT.The yearly variation in grain yield was related to simultaneous changes in spikelet number per panicle,grain weight,total biomass,and harvest index.Also,it was found that grain yield was positively correlated with internal N-use efficiency but negatively correlated with N requirements.It is concluded that grain yield and N requirements in hybrid rice when transplanted as single seedlings are not affected adversely by NT.The results of this study suggest that(1) compatible relationships among yield attributes can be established in hybrid rice that is transplanted as single seedlings,and(2) higher grain yield and higher N-use efficiency can be concurrently achieved in hybrid rice transplanted as single seedlings.

A Study of the Factors that Affect Safe Full Heading of Machine-transplanted Rice Seedlings in the Temperate and Cool Rice-growing Areas

This paper studies the factors that affect the safe full heading of machine-transplanted rice seedlings in the temperate and cool ricegrowing areas,and explores the influence of machine-transplanted rice seedling varieties,seedling age,nitrogen fertilizer application rate and management on the safe full heading of machine-transplanted rice seedlings. Results show that for the mechanized production in the temperate and cool rice-growing areas,we should select the mid-early maturity cold-resistant varieties with growth period of not exceeding 180 d,control the seedling age to be 30- 35 d and total amount of pure nitrogen to be not more than 300 kg / ha,and moderately reduce the nitrogen fertilizer postponing ratio. Under this condition,we can achieve safe full heading of machine-transplanted rice seedlings and ensure the yield.

Effects of Seed Rate on Root Twining Power and Seedling Quality of Machine-transplanted Super Rice

In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.

Effect of Seedling Raising Methods on Leaf Photosynthesis and Grain Yield of Mechanically-transplanted Japonica Rice

This study was conducted to investigate the effects of seedling raising modes on photosynthetic charactedsticsand grain yield under wheat straw returning. Four representative cultivars in Huaibei area were selected as test materials. By setting potted seedlings and carpet seedlings, the effects of different nursery meth- ods on the photosynthesis of rice at different growth stages in Huaibei area were investigated. Compared with carpet seedlings, the leaf area index of potted seedlings decreased at the maturation stage, but the dry weight of leaf shewed no significant difference.The SPAD of potted seedlings had an increasing trend after transplanting, but the SPAD increased differently according to cultivars. The net photosynthetic rate, stomatal conductance and transpiration rate of the leaves of pot seeding rice were significantly higher than those of carpet seedling rice on the 85^th d after transplanting. However, theintracellular CO2 concentration and water use efficiency of leaves had no significant differences between different ＇treatments. The results indicate that the photosynthetic capacity of flag leaves of pot seedling rice is stronger in early and middle stages, but the decay rate of photosynthetic function is slightly faster than carpet seedling rice, which might be the main reason for the rice yield of potted seedlings having no remarkable difference from carpet seedlings.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings （HLMS） on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar （Wuyunjing 23） was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, whJch was selected as the control. Root number, root twJstJng power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates andcontrol. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seed- lings. In the HLMS, the content of gibberellin acid （GA3） decreased while abscisic acid （ABA） content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

Why high grain yield can be achieved in single seedling machine-transplanted hybrid rice under dense planting conditions?

This study was conducted to identify the factors associated with high grain yield in single seedling machine-transplanted hybrid rice under dense planting conditions. Field experiments were done in Yong＇an Town, Hunan Province, China in 2015 and 2016. Two hybrid rice cultivars were grown under single seedling machine transplanting （SMT） and conventional machine transplanting （CMT） at a high planting density in each year. Grain yield and yield attributes were compared between SMT and CMT. Averaged across cultivars and years, grain yield was 12％ higher under SMT than under CMT. Plant height, basal stem width, and shoot and root dry weights were higher in seedlings for SMT than those for CMT. SMT had less maximum tiller number per m2 and consequently less panicle number per m2 than did CMT. Branch number per panicle, especially the secondary branch number per panicle, and spikelet number per cm of panicle length were more under SMT than under CMT, which resulted in more spikelet number per panicle under SMT than under CMT. SMT had higher or equal spikelet filling percentage than did CMT. The difference in grain weight between SMT and CMT was relatively small and inconsistent cross years. SMT had higher or equal total biomass and harvest index than did CMT. Dry weight per stem under SMT was heavier than that under CMT. Larger leaf area per stem was partly responsible for the heavier dry weight per stem under SMT than under CMT. Our study suggests that improvement in seedling quality, panicle size, and dry weight per stem are critical to the high grain yield in single seedling machine-transplanted hybrid rice under dense planting conditions.

Growth and yield of rice as affected by transplanting dates and seedlings per hill under high temperature of Dera Ismail Khan, Pakistan

Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill^-l on the productivity of rice in Dera Ismail Khan district of North West Frontier Province （NWFP）, Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 1 lth of July while sub-plots contained 1, 2, 3 or 4 seedlings hill^-1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with I seedling hill^-1. It explains that the use of more seedlings hill^-1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of I seedling hill^-1 is most appropriate for timely sowing otherwise 4 seedlings hill^-1 should be used to compensate for the yield gap in late transplanted rice.

Improving Transportation and Transplanting Efficiency of Flue-cured Tobacco by Transportation of Naked Seedlings

[Objective] The aim was to resolve the problem of low transportation efficiency of seedlings,vulnerability of seedling trays and difficulty of recycling.[Method]Naked seedlings were transported with trays and frames to improve transportation and transplanting efficiency.[Result] The transportation of naked seedlings would effectively reduce transportation cost and improve transportation and transplanting efficiency of tobacco seedlings.[Conclusion] The transportation of naked seedlings is suitable to be applied in the region with professional transplanting.

Study on Effect of Age of Seedlings Transplant on the Performance of Tomato （Lycopersicon esculentum） in a Southwestern Nigeria Location

Field trials were conducted at the experimental site of the Department of Plant Science of the University of Ado Ekiti, Nigeria during the 2005 and 2006 cropping season to examine the effects of age of transplanting on the performance of tomato Lycopersieon esculentum L. Establishment count %, plant height stem girth, earliness to flower, and fruit yield were significantly affected by the ages at which the seedlings were transplanted. The 2 and 3 weeks after sowing transplants were identical in performance and gave the highest number of field establishment count, growth increase, and yield. The 4WAS transplants performed better than the 5WAS transplants. It is concluded that a delay in early transplanting of tomato seedlings after 4WAS could lead to a very high reduction in tomato yield in the study area.

Research on Potted-Tray Grown Rice Seedling Transplanting by Machine

[Objective] In order to cultivate seedlings that are adaptable to farming system and transplanter, the technology for transplanting potted-tray grown rice seedlings with machine was introduced and studied. [Method] The transplanter-spe-cific seedlings were cultivated with potted-tray, bowl-shaped blanket tray and soft plastic flat plate respectively. The seeding rate and 20-50-day-old seedling height were investigated for the 3 sowing patterns. After the transplanting, the missing transplanting rate, upright seedling rate, seedling injury rate and green-returning pe-riod were investigated. [Result] Nursing seedlings with potted-tray had the advan-tages of saving seeds, high sowing precision, high seedling rate and high seedling rate. The 20-40-day-old seedlings had relatively high leaf age, seedling height and root number. However, 40 d after the transplanting, the growth of seedlings was slowed. The quality difference was smal est among the 20-day-old seedlings that were nursed with 3 different patterns, but since then the quality advantage of pot-ted-tray grown seedlings had been more and more prominent. There was smal dif-ference in quality among the 30-day-old seedlings. However, for the seedlings that were older than 40 d, the transplanting quality of potted-tray grown seedlings was higher than that of bowl-shaped blanket tray grown seedlings and soft plastic flat plate grown seedlings. In addition, the green-returning period of the potted-tray grown seedlings was significantly shortened. [Conclusion] Compared to the bowl-shaped blanket tray grown seedlings and soft plastic flat plate grown seedlings, the potted-tray grown seedlings were more suitable to transplant by machine in the wheat-rice double cropping areas of Chengdu Plain.

Effects of Farming and Seedling-raising Methods on Population Growth and Grain Yield of Mechanized Transplanting Rice

The effects of farming method, rice variety and seedling-raising method were studied on the population growth quality and grain yield of the mechanized transplanting rice by way of three-factor split plot design. The results showed that the no-tillage mechanical transplanting treatment was poorer than the conventional mechanical transplanting treatment in transplanting quality in general, but the former was similar to the latter in population growth quality. In regard to grain yield, the no-tillage mechanical transplanting treatment was lower than the conventional me- chanical transplanting treatment. Raising both pot-mat seedling and plastic-tray seedling did not make much difference in population growth and grain yield of mechanized transplanting rice, so both of the seedling-raising methods can be adopted according to practical conditions.

Organic Ginger (<i>Zingiber officinale</i>Rosc.) Development in a Short Temperate Growing Season: Effect of Seedling Transplant Type and Mycorrhiza Application

Global warming and consumer demand for medicinal plants present an opportunity to introduce ginger growth to the US Delmarva Peninsula. High tunnel and field studies were conducted to assess the development of organic ginger (Zingiber officinalis, Rosc) seedling transplants in mycorrhiza-amended soil. Transplant types were tissue culture derived with less than three tillers (TCS1), three or more tillers (TCS2), and nontissue culture derived (NTCS1). Transplants were grown with or without mycorrhiza (2.8 g per plant) in a split plot design with soil amendments as main plot and transplant type as subplot. Data were collected for air temperatures, plant height, tiller number, leaf chlorophyll index (LCI), rhizome fresh weight, plant biomass, rhizome nutrients, and levels of As and Pb. TCS2 transplants produced significantly higher, or trended to higher rhizome yield than transplants with less than three tillers, except for year two field study. The maximum rhizome fresh weight per plant was 648.3 g for TCS2 in high tunnel in year one. Generally, TCS2 had most tillers throughout the growing season ranging from 6.9 to 25.7 tillers per plant over three studies. Mycorrhiza had no effect on ginger height, tiller number, LCI or rhizome yield. Sustained high temperatures above 37°C, plus high light in the field caused dieback and stunted shoot growth in year two. There were no consistent effects of mycorrhiza or transplant type on rhizome nutrient content. Content of total Pb, As and other elements were at safe threshold levels for rhizome consumption. These results suggest that gingers grown from TCS2 transplants with at least three tillers yielded more rhizome than those grown from S1 transplants with fewer tillers. Introduction of ginger to a short season region such as the Delmarva may require consideration of environmental condition such as high temperature and light to which seedling transplants may be exposed in summer.

Contrast Test Between Direct Seeding and Seedling Transplanting of Diwangcai

To improve the yield of Diwangcai and explore its best cultivation way,direct seeding and seedling transplanting of Diwangcai were contrasted. The results showed that cumulative annual yield of Diwangcai by seedling transplanting was 16% higher than that by direct seeding.

Overlapped Tray Seedling Raising Model for Mechanical Transplanting of Rice

With the development of China's social economy,transfer of rural labors,and rise of labor costs,the rice production technologies are changing from manual operation to mechanical operation.The core of mechanical rice production is mechanical planting,while the key to mechanical planting is the seedling raising.On the basis of analyzing and studying the problems and experience of traditional mechanical transplanting of rice,a new overlapped tray seedling raising model was introduced.Main features of this model: substrate seedling raising and overlapped seedling tray.The seedling trays for seeding line are overlapped,and the overlapped trays are moved into the seedling room with controlled temperature and humidity.The temperature of the seedling room is controlled at 30-32℃,and the humidity of the seedling room is controlled at above 90%.After about 48 h,when the seedling height reaches 0.5 cm,move the seedling trays to the nursery.This model consists of one seeding center( seedling raising center) and N nurseries,to realize 1 + N seedling raising for mechanical transplanting of rice.One seeding center can provide seedlings for several hundred to several thousand hectares of mechanical transplanting of rice,and provide a new model for social services.This model could improve the quality of seedlings,increase the seedling survival rate by about 20%,reduce the seedling raising costs by 15%-20%,reduce the seedling raising risks,and greatly increase the utilization rate of the site and equipment of seedling raising center.

Effect of Transplantation in Different Seedling Age on Growth and Yield of Spring Maize in Shanxi Early Mature Area

In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design. Taking mulch based direct sowing as the control group,effects of transplantation in different seedling age on maize growing process,plant height,yield and composition factors of maize were analyzed.Results indicate that growing process of maize seedlings transplanted in different seedling age is slightly slower than the control group. Transplantation has the effect of reducing plant height. Although the yield of transplanted maize in different seedling age is lower than the control group. Besides,with the growth of seedling age of transplantation,the gap is widening. However,it is expected to realize mulch-free maize planting by transplantation in Shanxi early mature area. The yield of maize transplanted in two-leaf seedling age is not significantly different from the control group,and the yield is only 9% lower than the mulch-based direct sowing( CK). In conclusion,two-leaf period is the best seedling transplantation age for maize in Shanxi early mature area in this experiment condition.

不同育苗方式对机插秧苗素质、栽插质量及水稻产量的影响

为探明常规育苗、托盘育苗和漂浮育苗3种方式对水稻育苗及大田生长的影响,以‘南粳9108’为供试材料,比较相同播量下3种方式所育秧苗素质差异及对栽插质量、大田生长和产量的影响。结果表明:3种育苗方式成苗率在71.7%-75.0%,其中漂浮育苗最高,三者的地上部性状无显著差异,但常规育苗根系数量及长度较托盘育苗和漂浮育苗分别增加21.4%、16.1%和3.3%、9.8%;漂浮育苗的空穴率和伤秧率分别为0.39%、0.78%,栽插质量最优;漂浮育苗分蘖高峰期分蘖数较托盘育苗和常规育苗分别增加9.8%和24.0%,但单株生物量积累有所降低;漂浮育秧最终成穗数较托盘育苗、常规育苗增加7.2%和8.1%,但每穗实粒数降低4.9%、4.6%,在最终产量上三者之间无显著差异。综合来看,3种育苗方式都可育出健壮秧苗,并且栽插质量、大田生长和产量表现良好,在生产上可根据实际情况进行选择。

温室辣椒自动补苗机构控制系统设计与试验

针对辣椒培育过程中会出现一定量劣苗影响穴盘苗一致性,且目前移栽机械自动化程度低、移栽效果不理想的问题,依照农艺要求规范设计了机-电-气一体的自动补苗机构控制系统。阐述了自动补苗机构工作原理和系统结构,结合传感器和执行器布局和剔补苗运行机制设计了补苗机构控制系统软件和硬件。参照移栽手工作要求,设计气路系统并进行相关计算。对45天辣椒幼苗进行移栽补苗试验,以水平移动速率、取苗深度、含水率为试验因子,剔苗成功率、移栽成功率为衡量指标,设计三因素三水平正交试验,结果表明:水平移栽速率对剔苗成功率和移栽成功率影响较小,移栽手运行平稳,剔苗成功率平均值为94%,移栽成功率为91.1%,表明自动补苗机构性能可靠。

辣椒漂盘苗机械化移栽适应性研究

为了探索辣椒漂盘苗对机械化移栽的适应性,以贵州某辣椒基地所育适栽期辣椒漂盘苗和2ZB-2旱地吊杯鸭嘴式移栽机为测试对象,完成了辣椒苗形态特征参数测量、落苗基质损失及田间机械栽植的试验研究。结果表明:从辣椒苗的苗高、叶面展幅、基质情况来看,所育漂盘苗基质饱满,且适于膜上移栽常用的鸭嘴式栽植器;漂盘苗基质含水率在56.4%~63.5%时,利于机械移栽的基质保持;田间机械移栽的栽植深度合格率、漏栽率、伤苗率分别为76.7%、2.4%、3.2%,满足指标要求;直立度合格率为88.7%,低于93%的指标下限。总体来说,辣椒漂盘苗与移栽机适应性较好,基本能达到贵州辣椒机械化栽植作业要求。