Growth and Nutritional Responses of Juvenile Jeffrey Pine to Post-Planting Fertilization

Abstract

Broadcast fertilization of a three-year-old Jeffrey pine (Pinus jeffreyi Grev. & Balf.) plantation growing on an eroded Sierra Nevada site was examined for its capacity to enhance seedling growth. The amendments chosen for the study included controlled release and conventional soluble formulations that contained a variety of N forms, but all featured high N content along with other nutrients. Four application rates were used, and all amendments were distributed around the base of the seedlings as top dressing. Four seasons after treatment application, fertilized seedlings were 129% larger in height, 93% larger in diameter, and 865% greater in shoot volume than unfertilized seedlings overall. Seedling sizes generally increased with application rate, and by a small margin, the controlled release fertilizer outperformed the other formulations. Relative growth analysis suggested that stimulation by the amendments would continue beyond four seasons. Foliar analysis conducted early and again late during the study revealed that N and P concentrations were consistently raised by fertilization, which likely accounts for much of the accompanying growth gains, while Ca, Fe, Mn, B, and Al concentrations were consistently reduced. Either early or late, foliar K was also raised while Mg, S, Zn, and Cu were reduced. Collectively, these results indicate that fertilization with a variety of high N formulations can increase the availability and uptake of critical nutrients sufficiently to impart in Jeffrey pine on low quality sites a substantial growth advantage.     

5%桉油精可溶液剂防治杨小舟蛾幼虫效果的研究

进行了不同浓度5%桉油精可溶液剂对杨小舟蛾防治效果的田间试验,以及2000倍的烟碱·苦参碱进行田间对比试验,结果表明:5%桉油精可溶液剂1500倍对杨小舟蛾防治效果较好,喷药后5d防效为100%。试验结果为今后5%桉油精可溶液剂防治杨小舟蛾的合理农药配比浓度提供科学依据。     

Vermicompost leachate improves seedling emergence and vigour of aged seeds of commercially grown Eucalyptus species

Vermicompost leachate (VCL) is a liquid generated by earthworms and microorganisms during the conversion of organic matter into vermicompost. Vermicompost leachate is rich in nutrients and believed to contain both known and unknown plant growth substances, which are beneficial to plants. Four-year-old seeds (artificially aged) of Eucalyptus dunnii, E. nitens and E. smithii were subjected to VCL at different concentrations. In comparison to the control, the percentage of emerged seedlings of all three species improved significantly (p < 0.05) by more than two to three times when treated with VCL. Treated seedlings showed better growth performance than untreated ones at both first and second harvest, 75 and 150 d after sowing, respectively. Eucalyptus dunnii achieved the highest seedling vigour index (SVI) at the lowest VCL concentrations of 1:5. In contrast, the SVI of E. nitens was maximum at the highest concentrations of VCL (1:20). The best SVI of E. smithii was obtained at VCL concentrations of 1:10. These results suggest that the influence of VCL on SVI of the eucalypt species tested was concentration-dependent. The absolute seedling vigour rate per day was also improved with all the tested concentrations of VCL, with some exceptions for E. dunnii seedlings. The order of response to VCL by the species can be summarised as E. smithii > E. nitens > E. dunnii. The results of this study suggest that VCL can be used to supplement chemical fertilisers. The liquid nature of VCL should be convenient for application both under nursery and field conditions. However, trials under field conditions are required.     

不同粒径的桉树皮基质对桉树苗木的影响

以桉树皮为材料,通过对3种粒径桉树皮基质理化性质分析和苗木调查,研究不同粒径对基质理化性能和育苗效果的影响。试验结果表明：在育苗过程中,粒径〈2mm的桉树皮基质理化性质相对更稳定,苗木生长量最大,育苗效果最好;粒径2～5mm和5～10mm的桉树皮基质理化性质变化较明显,而粒径5～10mm的基质孔隙性变化最大,化学性质不够稳定,粒径对育苗基质和育苗效果影响较大。     

Delivering Fertilizers Through Seed Coatings

Summary

Coating seeds with nutrients may be an effective way of supplying starter fertilizer for establishment of seedlings and early growth. However, a large variability in benefits of providing nutrients with seeds has been reported, highlighting differences in the implementation of the techniques. This chapter will discuss the main principles relating to the imprecisely defined concept of nutrient-amended seeds.     

水稻双无育秧法试验研究

针对承德稻区水稻育秧过程中出现了一系列突出问题,承德市农业技术推广站对该地区育秧技术进行试验探索,集成了"水稻双无育秧法",结果表明,双无育秧法秧苗期温湿度容易控制,基本保持在20℃左右,适合秧苗生长;基质透气、透水性强,不携带各类病菌,避免了土传病菌的侵害;水稻秧苗根系发达,根须比常规育秧多一倍,根粗、根壮,比常规育苗根长2～3 cm;水稻苗期立枯、青枯、黄化病没有发生,秧苗株型合理、根系发达、带孽率高、插秧后缓苗快;比常规育秧增产3%～4%,效果显著。     

杂交水稻制种母本机械化育插秧技术

介绍了杂交水稻制种母本机械化育插秧技术,主要包括调整好父母本播差期、母本软盘育秧要点、适时机插、合理运筹肥水等.     

机插密度对连作晚稻“甬优6号”产量的影响

[目的]研究机插密度对连作杂交晚稻"甬优6号"产量的影响,明确其合理的群体起点,为连作稻区晚季杂交稻机插技术的推广提供科学依据。[方法]根据插秧机设计的行株距规格,设栽插丛数为12万、15万、18万、21万和24万丛/hm25个处理,采用小区重复试验,对产量进行方差分析。[结果]随着机插密度的增加,单位面积最高苗数、有效穗增加,穗粒数减少,成穗率降低;机插密度过高或过低均不利于增产增效。[结论]"甬优6号"在温州地区作连作晚稻种植,机插密度以21万丛/hm2左右,每丛插2.5～3.5本较适宜。     

烤烟“井窖式”移栽技术推广总结

"井窖式"移栽技术在地膜覆盖或露地栽培的基础上,融合了小苗移栽技术、深栽技术,能较好地营造适宜烟苗生长的微环境,实现了减工降本、提质增效。综述了该移栽技术的主要优势及推广过程中出现的问题,并提出了相关对策。     

怒江山茶与白花油茶不同嫁接组合苗根系生长特性对比

[目的]研究油茶不同砧穗芽苗砧嫁接效果。[方法]以3种油茶不同砧穗组合嫁接苗为试验材料,对不同砧穗组合嫁接苗根系的各项指标(根系长度、根系表面积、根系投影面积、根系体积、根尖数等)进行测定和分析。[结果]本砧嫁接苗在地下部分根系的各指标生长状况上相比采用不同种砧穗嫁接的苗木占有更显著的优势。白花油茶本砧嫁接苗的主根直径较大,为4.758 mm,其主根较为发达;怒江山茶本砧嫁接苗根系的细根较为发达,在根径级d≤0.5 mm中,从根系长度、根尖数、根系表面积、根系投影面积各方面都表现为最大,分别为:959.20 cm、1 602条、61.59 cm2、19.61 cm2。[结论]可培育白花油茶(接穗)怒江山茶(砧木)嫁接苗,为农民增收、提高生产效益提供有效途径。