Growth of tandem long-mat rice seedlings using controlled release fertilizers:Mechanical transplantation can be more economical and high yielding

The traditional soil-based rice seedling production methods for mechanical transplanting are resource-intensive,time consuming and laborious.The improvement and optimization of nutrient management in soil-less nursery raising methods like tandem long-mat seedlings(TLMS)are necessary for the resource-efficient cultivation of rice.In the present study,a controlled-release fertilizer(CRF)-polymer-coated compound fertilizer with 3 months release period(PCCF-3M)was applied as seedling fertilizer(SF),and five different dosages of SF(SF-0,SF-10,SF-20,SF-30,and SF-40)were compared with an organic substrate as the control(CK).Among all SF treatments,the best results were obtained with the application of 20 g/tray of SF(SF-20),as the seedling quality and machine transplanting quality were comparable to those of CK.In contrast,the lower dosages(SF-0 and SF-10)resulted in low nitrogen content and reduced shoot growth,while the higher dosages(SF-30 and SF-40)resulted in toxicity(increased malondialdehyde accumulation)and inhibited the root growth.Similarly,SF-20 increased panicle number(5.6-7.0%)and yield(4.3-5.3%)compared with CK,which might be related to the remaining SF entangled in the roots supporting the tiller growth of rice seedlings in the field.Moreover,SF-20 reduced the seedling block weight(53.1%)and cost of seedling production(23.5%)but increased the gross margin,indicating that it was easy to handle and economical.Taken together,our results indicate that SF-20 is a cost-effective way to promote the growth and transplanting efficiency of rice seedlings.To our knowledge,this study is the first to determine the optimum dosage of CRF for the soil-less production of rice seedlings.

Effects of Different Seed Coating Agents on the Quality of"Grey-matter"Hybrid Rice Seeds

[Objectives]This study was conducted to select suitable mixed seed coating agents for improving the quality of"grey-matter"hybrid rice seeds.[Methods]Three different mixed seed coating agents(A,B,C)were used to coat the seeds of two varieties(Taiyou 390 and Zhenliangyou 8612)of hybrid rice with different"grey-matter"content(5%,15%,25%),and the results were investigated and compared.[Results]The combinations of treatment B(seed coating agent A+Linong)and treatment C(Manshijin+seed coating agent A)could significantly improve indexes including seed germination potential,germination rate,seed vigor,seedling height,fibrous roots and fresh weight of the two varieties with a"grey-matter"content greater than 15%,but had no significant effects on main root length,dry weight,leaf number and tiller number,and the effects of treatment B was better than those of treatment C.That is to say,mixed seed coating agent B(seed coating agent A+Linong)was suitable for use as a seed coating agent to improve the quality of"grey-matter"seeds.[Conclusions]This study provides a reference plan for the safe use of mixed seed batches with"grey-matter"deterioration.

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.

Effects of Seed Soaking with Uniconazole and Substrate Formula on Seedling Quality of Rapeseed

[Objective] To cultivate blanket rapeseed seedlings suitable for automatic mechanical transplanting, the effects of seed soaking with uniconazole and substrate formula on seed germination and seedling quality of rapeseed were investigated using HY4 as the material. [Method] The rapeseed seeds were soaked in different concentrations（0, 5, 10, 20, 30, 40 and 50 mg/L） of uniconazole for 0, 1, 2, 4 and8 h, respectively. Subsequently, they were dried naturally. After the preliminary screening carried out in petri dishes and in a laboratory, the optimum soaking concentration and time of uniconazole were obtained. On the other hand, the rapeseed seeds were soaked in different concentrations（0, 5, 10, 15 and 20 mg/L） of uniconazole for 0, 1 and 2 h, respectively for outdoor pot experiment. At the same time, the screening of optimum substrate formula for cultivating blanket rapeseed seedlings was carried out. The field test was carried out to verify the screened optimum substrate formula. [Result] The results of petri dish experiment showed that seed soaking with uniconazole could delay seed germination, reduce seed germination rate, inhibit hypocotyl elongation and promote root growth. When the soaking concentration exceeded 30 mg/L and soaking time exceeded 2 h, the effect of seed soaking with uniconazole on seed germination was greater, and the seed soaking inhibited root growth. The results of outdoor pot experiment showed that the soaking concentrations and times all significantly reduced seedling height, slowed shoot growth and promoted root growth, which all contributed to the cultivation of blanket rapeseed seedlings suitable for automatic mechanical transplanting. In the substrate formula, the lower the proportion of soil was, the better the seedling growth was. In the substrate with lower proportion of soil, the seed germination rate, plant height,root vigor and dry matter accumulation were all increased（P〈0.05）, which was verified by the field test. When the soaking concentration was less than 10 mg/L and soaking time was less than 1 h, the uniconazole showed weaker regulation effect on seedling growth, and the rapeseed seedlings were higher. In the substrate with soil proportion less than 50%, the adequate fertility relatively weakened the regulation effect of uniconazole on seedling growth, and the rapeseed seedlings were larger. [Conclusion] When the soaking concentration ranged within 15-20 mg/L and soaking time ranged within 1-2 h and the proportion of soil in substrate was 50%,the height of cultivated rapeseed seedlings was less than 18 cm, there were 5-6leaves remained on each plant and the nursing period was shortened to 30-40 d,which were all beneficial to industrial production.

Study on Seedling Quality of Double-cropping Late Rice Sowed at Different Dates in Guangdong

[Objective] The aim was to study seedling quality of rice sowed at different dates so as to provide theoretical basis for determining the best seeding time.[Method] By investigating the characters of shoot and root of different varieties sowed at different dates,the best seeding time of double-cropping late rice was determined.[Result] The first leaf sheath height and the second leaf length shared significantly positive correlation,which fit the quadratic equation well.The effects of different sowing dates on shoot and root of three rice varieties appeared significant difference.[Conclusion] The best seeding time of Tianyou428 was in June 25-July 2 and that of Tianyou998 and Yuxiangyouzhan was in July 2-9.

Effects of Different Upland Seedling Nurturing Modes on Shed Temperature and Rice Seedling Quality

In order to compare the advantages and disadvantages of large-shed,middle-shed and small-shed upland seedling nurturing modes in japonica rice planting regions of North China, in this study, Tongyin 58, Tonghe 836 and Tonghe 835 were used as experimental materials and cultivated with large-shed, middle-shed and small-shed upland seedling nurturing modes to investigate active and effective accumulated temperature and rice seedling quality. According to the results, active and effective accumulated temperature in three different upland seedling nurturing treatments during seedling nurturing period were generally in a descending order of large shed 〉 middle shed 〉 small shed. The occurrence frequency of temperature exceeding the biological upper limit for rice growth in different upland seedling nurturing treatments demonstrated a descending order of large shed 〉 small shed 〉middle shed; the occurrence frequency of temperature below the biological lower limit demonstrated a descending order of small shed 〉 middle shed 〉 large shed.Plant height, root number, aboveground dry weight, underground dry weight and emergence rate varied significantly among different upland seedling nurturing modes,which showed a descending order of large shed 〉 middle shed 〉 small shed; leaf age and stem number in large shed was significantly higher than that in middle and small sheds, but there was no significant difference in leaf age and stem number between middle and small sheds; underground dry weight varied slightly between large and middle shed, but underground dry weight in large and middle shed was remarkably higher than that in small shed. In production, large-shed upland seedling nurturing is most appropriate technique, followed by middle-shed upland seedling nurturing. In large-shed upland seedling nurturing, ventilation and seedling hardening should be strengthened. Small-shed upland seedling nurturing technique is not recommended to be used in regions with low accumulated temperature at night. In small-shed upland seedling nurturing, the minimum temperature at night should be concerned, and heat preservation measures should be taken immediately when there is a sudden drop in temperature.

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.

Coinoculation of bioinoculants improve Acacia auriculiformis seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.

Effects of SSA Dosages on Seedling Quality and Yield by Mechanical Transplanting

[Objective] The aim was to research the influence of gradient dosages of seedling-strengthening agent （SSA） on rice seedling quality and yield. [Method] The influence of four dosages of SSA on late rice seedling quality and yield was investi- gated, using Oryza sativa cv. Yongyou 9 and Huanghuazhan as test materials. [Re- sult] The results showed that applying SSA significantly increased several indexes of seedling quality including the leaf age, basal stem width and dry matter weight. In addition, SSA greatly increased the rice yield, mainly through influencing two yield component factors, effective panicle number and grain number per panicle. [Conclu- sion] SSA was beneficial to nurse strong seedling which satisfied mechanical trans- plant and improve yield. Considered both seedling quality and yield trait, the optimal SSA dosage is 50 g/m2 under this cultivating condition.

The effects of fall fertilization on the growth of Chinese pine and Prince Rupprecht’s larch seedlings

Nutrient loading in the fall is a practical way to improve seedling quality and has been proven to increase nutrient accumulation,translocation and utilization.Few studies have reported on the variation in free amino acids as a result of fall fertilization,especially for diff erent seasonal needle habits(evergreen,deciduous).Therefore,a balanced two-factor factorial design with one fall fertilization treatment(10 mg N/seedling)and Chinese pine(Pinus tabulaeformis Carr.)and Prince Rupprecht’s larch(Larix principis-rupprechtii Mayr.)seedlings was used to examine growth response over one nursery season.Associated changes between fall fertilization,N storage and free amino acids were analyzed.Results showed that:(1)stem height,diameter and biomass for both species were similar between controls and fall fertilization treatments;(2)compared to controls,fall fertilization increased Chinese pine needle and root N by 17.7%and 36.9%,respectively.For Prince Rupprecht’s larch,fall fertilization resulted in 26.3%and 34.54%more N in stem and roots,respectively,than controls;(3)the three main amino acids in control and fertilization treatments in Prince Rupprecht’s larch seedlings were glutamine,arginine and proline,and in Chinese pine seedlings were glutamine,arginine andγ-amino butyric acid;(4)total amino acid contents were not signifi cantly increased by fall fertilization,but glutamine in Chinese pine and Prince Rupprecht’s larch increased by 64.2%and 35.2%,respectively.Aboveground biomass of Prince Rupprecht’s larch had higher proline contents than Chinese pine,which suggests that the stress resistance of the aboveground tissue may be higher for Prince Rupprecht’s larch.The results indicate that diff erent plant organs with various response are well adapted to nitrogen loading for nutrient storage in evergreen and deciduous conifer seedlings.

Effects of Organic Fertilizer Application Amount on Seedling Quality under No-tillage Semi-Solid State Direct Seeding

With early rice variety Zhongzao 39 as test material,this paper investigated the effects of organic fertilizer application rate on seedling quality under no-tillage semi-solid state direct seeding.The results showed that the seedling quality of no-tillage semi-solid direct seeding was better than that of traditional direct seeding,and different application rates of organic fertilizer under no-tillage semi-solid direct seeding also had signi ficant effects on seedling emergence rate,dry matter weight in ground and underground,stem base width,root activity,chlorophyll content and seedling growth index of rice seedlings.When the organic fertilizer dosage was A4(0.10∶1),it was most beneficial to the growth and development of rice seedlings under no-tillage semi-solid state direct seeding,it could effectively improve the quality of rice seedlings and enhance their resistances,the cultivated seedlings could lay a good foundation for high yield of rice in late stage.

A Study on Seedlings' Density of Aralia elata

Aralia clata is an important economic species in northeast China. The experiments for determung optimum seedlings density were made in the nursery of Experimental Forest Farm of Liaoning Province. Qingyuan County, in 1997. The results of 4 repeating experiments for six densities were analyzed using variance analysis by single factor. Seedling density has great effects on growth of diameter(at foot) and height. The proper seedlings density forAralia elata was determined to be 55–65 stems/m2, or 330000 390000 hm2. Thus density can insure individual seedling’s quality and the maximum productivity of seedlings.

Effect of Seedling Quality on Growth,Yield and Quality of Angelica sinensis

[Objectives]Aiming at the problems of high bolting rate,low yield and poor quality traits in the production of Angelica sinensis in Qinghai Province,this study investigated the effect of seeding quality on the growth,yield and quality of A.sinensis.[Methods]Field experiments were carried out in five aspects,including different seedling shapes,different seedling sizes,different seedling ages,different seedling raising methods,and different seedling sources.The effect of seedling quality on the survival rate,bolting rate,main quality traits(root length,root fresh weight,root head thickness,root head length)and yield of A.sinensis was investigated.[Results]The seedlings,0.2-0.5 cm in diameter,100-110-d old,raised from three-year-old provenance in cultivated land by conventional method,were more preferable,and their survival rate was high,bolting rate was low,yield is high,and quality traits performed well.[Conclusions]The seedlings,0.2-0.5 cm in diameter,100-110-d old,raised from three-year-old provenance in cultivated land by conventional method,were more preferable,and their survival rate was high,bolting rate was low,yield is high,and quality traits performed well.

Cultivation Density of Toona ciliate

ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2.

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 Seedling Cultivation Methods on Seedling Cultivation of Major Vegetables

Objective] The alm was to expIore the effects of cuItivation methods on vegetabIe growth in seedIing stage. [Method] The test incIuded 4 treatments, as foI-Iows： treatment 1 （T1） where seedIings were cuItivated as per water fiIm-based cuI-tivation and irrigation proceeded reguIarIy; treatment 2 （T2） where irrigation proceed-ed continuousIy as per water fiIm-based cuItivation; treatment 3 （T3） where seedIings were cuItivated as per fIoating nursing; controI treatment （CK） where seedIings were cuItivated as per seedIing-tray cuItivation in order to survey the number of germinated seedIings per tray. [Result] Both of water fiIm-based cuItiva-tion and fIoating nursing took advantages in germination speed and aduIt seedIing rate, compared with tray cuItivation method. [Conclusion] Water fiIm-based cuItivation and fIoating nursing make innovations in water management during seedIing cuItiva-tion, which improve germination speed, aduIt seedIing rate and seedIing quality, making contribution to Iarge-scale production of greenhouse vegetabIes through ap-pIications and practices.

The Application of Seedling Nursing on Moist Trays and Fermentation Heating Using Farmyard Manure Methods in High-altitude Tobacco Areas of Fenggang County

To solve the problems of long seedling culture time and poor quality of tobacco seedlings bred by floating culture technique of seedlings in high-altitude tobacco areas, a comparative trial between seedling nursing on moist trays ＋ fermentation heating using farmyard manure and conventional floating culture of seedlings in Fenggang County was carried out in 2013. The results showed that seedling nursing on moist trays ＋ fermentation heating using farmyard manure can improve 4-5 ℃ of pool water temperature, shorten 8 d of seedling age, increase 4.45 cm of seedling height, thicken 0.46 cm of stem girth and make lateral root system developed. The method can shorten the time of floating breeding of flue-cured tobacco,improve the quality of tobacco seedlings, thus it was suitable to popularize in highaltitude tobacco areas of Fenggang County.

Studies on Electrolyte Conductivity and Activity of Dehydrogenase of Chinese Fir and Masson Pine Bare-Root Seedling under Water and Cold Stress

The electrolyte conductivity and activity of dehydrogenase of bare-root seedlings of both Chinese fir (Cunningha-mia lanceolata (Lamb.) Hook.) and Masson pine (Pinus massoniana Lamb.) under freezing and desiccation treatments were studied. The results showed that needle electrolyte conductivity of both species increase significantly after freezing treatment and there are no significant differences in needle electrolyte conductivity between the two species. The dehydrogenase activity (ARD) of fine roots of both Chinese fir and Masson pine was negatively correlated with increasing freezing and desiccation. The results suggest that both electrolyte conductivity and dehydrogenase activity could be used as quick indicators of Chinese fir and Masson pine bare-root seedling quality.

Field Performance of Quercus bicolor Established as Repeatedly Air-Root-Pruned Container and Bareroot Planting Stock

Benefits of repeated air-root-pruning of seedlings when stepping up to progressively larger containers include excellent lateral root distribution immediately below the root collar and an exceptionally fibrous root ball. To evaluate long-term field performance of repeatedly air-root-pruned container stock, three plantings of swamp white oak (Quercus bicolor Willd.) 10 to 13 years old were located that also included bareroot planting stock. Initial and final stem diameter and height and above-ground green weights were determined on randomly selected trees at each site. On a site with a sandy, excessively drained, high pH soil, trees (age 10) from container stock were 1.5 times taller, 2.3 times larger in dbh, and 2.8 times greater in green weight than trees from bareroot stock which averaged only 2.9 m tall, 3.9 cm dbh, and 16.3 kg green weight. On a site with high clay, poor internal drainage, and frequent flooding, trees (age 12) from container stock were 1.4 times taller, 1.8 times larger in dbh, and 4.1 times greater in green weight than trees from bareroot stock which averaged 4 m tall, 7.3 cm dbh, and 28 kg green weight. On an upland site with deep loess soils, there was a trend for trees (age 13) from container stock to be only slightly larger than trees from bareroot stock with each stock type averaging 9.6 m tall, 20 cm dbh, and 177 kg green weight. Repeated air-root pruning produced lateral roots immediately below the root collar that resulted in large container stock with large well-balanced root systems that were competitive on harsh or less than ideal oak sites. Although the process is relatively labor intensive, propagation of repeatedly air-root-pruned container stock is readily adaptable internationally to locally available sources of organic matter and open-bottom containers.