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 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, which was selected as the control. Root number, root twisting power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates and control. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seedlings. In the HLMS, the content of gibberellin acid(GA_3) 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.

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.

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.

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.

Effects of different machine transplanting methods on the physiological and yield characteristics of late rice in China

To address problems caused by rice machine transplanting such as injury to the seedlings and recovery period that extend growth period,this study explored the effects of different machine transplanting methods on the physiological and yield characteristics of late rice in China,and determine the appropriate machine transplanting method for late rice,which was expected to provide a basis for high-yield and high-efficient cultivation of machine-transplanted late rice.Hybrid indica rice Taiyou 398 and conventional indica rice Jing Gangruanzhan were selected as the research objects,and large-pot carpet seedling machine transplanting(M1),conventional pot carpet seedling machine transplanting(M2)and ordinary carpet seedling machine transplanting(M3)were adopted respectively to analyze their effects on seedling quality,population physiological characteristics,yield and its components and economic benefits of late rice.The results showed that compared with M2 and M3,M1 achieved higher seedling quality,showing significant advantages in the early stage despite average root entwining force that met the requirement of machine transplanting.The seedlings transplanted using M1 had shorter recovery period after mechanical transplanting,with earlier tillering,earlier peak seedling,and slower declining of stems and tillers in the late stage;the peak seedling number was not high,but the effective tiller number and earbearing tiller percentage were significantly higher than those achieved by the other two machine transplanting methods.Also,M1 achieved stronger photosynthetic capacity of flag leaves before HS,with more photosynthetic products in stems and leaves transported to panicles and more efficiently after HS.Compared with seedlings transplanted using M2 and M3,the recovery period of those transplanted using M1 was shortened by 3 and 5 d,the heading stage(HS),and maturity stage(MS)were advanced,which effectively reduced the risk and impact of“cold dew wind”on machine-transplanted late rice.M1 had significant yield increase advantage and economic benefit,with better grain maturity,and“larger panicles,more panicles,more and fuller grains”.M1 achieved an average yield increase of 10.31%-11.10%,20.67%-25.10%in 2 years,and an average income increase of 18.65%-131.06%and 62.85%-323.78%,respectively.Therefore,vigorously developing M1 is the key to the high-yield and high-efficient cultivation of machine-transplanted late rice in China.