Coarse soil can enhance the availability of nutrients from fine soil          下载免费PDF全文

Simeon J. Smaill  Peter W. Clinton  Robert B. Allen  Alan C Leckie  Murray R. Davis 《植物养料与土壤学杂志》2014,177(6):848-850

A recent trial found that the presence of coarse soil in fine soil increased nutrient uptake by two plant species (Smaill et al., 2014 ). To determine if the additional nutrient uptake was derived directly from the coarse soil, the changes in coarse soil nutrient stocks were assessed. In most cases nutrient stocks increased, despite being associated with greater plant nutrient uptake. This suggests coarse soil can promote nutrient release from fine soil through some currently unknown mechanism.  相似文献   

Placement of soil moisture sensors in sprinkler irrigated potatoes     

Timothy D. Stieber  Clinton C. Shock 《American Journal of Potato Research》1995,72(9):533-543

Potato (Solanum tuberosum L.) is particularly sensitive to soil water potential below ?50 to ?60 J kg^?1 during tuber development. Soil water must also be carefully monitored to irrigate efficiently and to minimize nitrate leaching associated with over-irrigation. Water distribution in and below potato hills during and following sprinkler irrigation was monitored using granular matrix sensors (Watermark Model 200, Irrometer Co., Riverside, CA) placed in 0.10 m × 0.15 m cross-sectional grids down to 0.6-m depth below the soil surface. Each grid consisted of 26 sensors. Sensor electrical resistance had been calibrated to soil water potential. During one test, soil water potential was intentionally lowered to levels drier than ideal for potato to emphasize soil wetting and drying patterns. Over the 26 locations in the grids, the soil water potential averaged ?33 J kg^?1 over a six week period, with sprinkler irrigations evenly rewetting the upper 0.2 m of the hill. On average, the driest locations were the top of the hill, directly under the hill, and below the furrow with wheel track compaction. Ideal sensor locations for monitoring soil water status and scheduling irrigations are offset 0.15 m from the center of the hill and 0.1 to 0.2 m deep. Sensors installed in silt loam soil responded within four hours to wetting and within 12 hours to drying, the shortest increments of time measured.  相似文献   

Potato tuber stem-end fry color determination     

Clinton C. Shock  Tim D. Stieber  James C. Zalewski  Eric P. Eldredge  Michael D. Lewis 《American Journal of Potato Research》1994,71(2):77-88

Precise measurement of tuber stem-end fry color is necessary to determine the fry quality of potatoes (Solanum tuberosum L.). Changes in fry color as influenced by small variations in measurement location, delays between slicing and frying, and delays between frying and measuring were examined. Variations in time between frying and measurement, and variations in the location of measurement contributed more to changes in observed color than delays between slicing and frying. The standard visual method for determining stem-end fry color was compared to objective methods using a Photovolt reflectance meter. Photovolt reflectance readings of two types of transverse stem-end tuber slices were compared with those from longitudinal strips. All methods produced closely related re-sults. Optimum sample size and applications for each method are discussed.  相似文献   

Soil quality relationships with tree growth in exotic forests in New Zealand     

Craig W. Ross  Michael S. Watt  Roger L. Parfitt  Robyn Simcock  John Dando  Graham Coker  Peter W. Clinton  Murray R. Davis 《Forest Ecology and Management》2009

Quantitative information on the relationships between site quality and plantation productivity (dominated by the exotic species Pinus radiata) is required to achieve goals for sustainable forest production. Soil quality is a key component of site quality. A nationwide study of soil quality measurements is reported for 35 representative forest sites, covering a wide range of climatic and edaphic conditions found throughout New Zealand's plantation forest estate, representing most of the soils used for plantation forestry in New Zealand. The objectives of the study were to find the most important soil properties that discriminated among eight New Zealand Soil Orders and determine relationships between Soil Orders and early tree growth rates for P. radiata and Cupressus lusitanica. Soil physical and chemical properties were measured to identify key soil indicators of soil quality related to tree productivity. Tree growth was measured after four years on small plots planted at very high stand density (40 000 stems ha⁻¹). A factorial design was used to examine the influence of three factors on tree productivity: two species, P. radiata D. Don (ectomycorrhizal) and C. lusitanica Miller (endomycorrhizal); with and without fertilizer; and low or high disturbance (soil compaction and/or topsoil scalping by machinery). Carbon content, Phosphorus (P) retention, and soil physical properties that index the degree of soil compactness were strongly correlated to Soil Order. These properties are similar to soil quality factors that correlated with tree growth. Discriminant analyses of soil quality parameters by Soil Order clustered soils based on P retention (phosphate absorption capacity), subsoil Carbon (C), and subsoil air capacity (volume % of voids at 10 kPa matric potential). Allophanic Soils and Podzols clustered (from plots of first versus second canonical variates) separately from the other Soil Orders, which were somewhat clustered on the second variate within a broad clustering on the first variate. Soil Orders were ranked for tree growth rates for both species: pumice Andisols > Inceptisols > tephric Andisols > Entisols > Ultisols > Spodosols (NZ classification: for P. radiata is Pumice > Brown > Pallic > Allophanic > Recent > Raw > Ultic > Podzol and for C. lusitanica Pumice > Pallic > Allophanic > Brown > Raw > Ultic > Recent > Podzol).  相似文献   

Nitrogen fertiliser effects on litter fall, FH layer and mineral soil characteristics in New Zealand Pinus radiata plantations     

Simeon J. Smaill  P.W. Clinton  L.G. Greenfield 《Forest Ecology and Management》2008,256(4):564-569

The effects of nitrogenous fertilisation on litter fall, FH layer and soil characteristics were investigated in replicated trials in six second rotation New Zealand Pinus radiata plantation forests. Four trial sites also incorporated three different post-harvest organic matter removal treatments. All sites were sampled in early 2002 and 2003. Fertilisation significantly increased the nitrogen content and decreased the carbon:nitrogen ratio of the litter fall. Fertilisation significantly increased the mass of the FH layer in the treatment plots, moisture content in the FH layer, the concentration of nitrogen in the FH layer and the pool of carbon and nitrogen stored in the FH layer. Fertilisation significantly increased the nitrogen concentration of the mineral soil, and decreased the mineral soil carbon:nitrogen ratio and pH. Several significant site × fertilisation interaction terms indicated that variations in the fertilisation regimes and site characteristics substantially influenced the effects of fertilisation. Fertilisation did not significantly decrease the relative differences between the organic matter removal treatments. The significant differences in the litter fall, FH layer and mineral soil characteristics strongly suggest that nitrogenous fertilisation has the capacity to significantly alter the forest floor environment, and may be able to increase carbon storage over the life of the rotation.  相似文献   

Bovine Herpesvirus Type 1 (BHV-1) is an Important Cofactor in the Bovine Respiratory Disease Complex     

Clinton Jones  Shafiqul Chowdhury 《Veterinary Clinics of North America: Food Animal Practice》2010

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Delayed pasture germination allows improved rigid ryegrass (Lolium rigidum) control through grazing and broad-spectrum herbicide application     

Graeme J. Doole  Clinton K. Revell 《Crop Protection》2010

Eastern star clover (Trifolium dasyurum C. Presl.) is a new pasture legume developed for use in short phases between extended cropping sequences in Western Australian dryland agriculture. Its delayed germination provides an opportunity to obtain almost complete control of the highly-competitive crop weed rigid ryegrass (Lolium rigidum Gaudin) through non-selective herbicide application and/or grazing. Given the recent development of a commercial cultivar of eastern star clover (cv. AGWEST^® Sothis), a complex simulation model is used to evaluate its potential profitability relative to continuous-cropping and rotations employing a popular pasture, French serradella (Ornithopus sativus Brot. cv. Cadiz). The profitability of those sequences containing eastern star clover is robust to high initial ryegrass populations and increasing severity of herbicide resistance. Moreover, the weed control benefits accruing to this pasture's delayed germination are of sufficient magnitude to offset the low establishment cost and higher biomass production of French serradella. This highlights the value of eastern star clover to producers in the Western Australian wheatbelt and offers an additional trait that plant breeders and selectors can exploit when seeking to expand weed control options in land-use sequences.  相似文献   

Genetic Fingerprinting of Potato Varieties from the Northwest Potato Variety Development Program     

Sapinder Bali  Vidyasagar Sathuvalli  Chuck Brown  Rich Novy  Lorie Ewing  Jeanne Debons  David Douches  Joseph Coombs  Duroy Navarre  Jonathan Whitworth  Brian Charlton  Solomon Yilma  Clinton Shock  Jeff Stark  Mark Pavek  N. Richard Knowles 《American Journal of Potato Research》2017,94(1):54-63

The Northwest Potato Variety Development (NWPVD) Program has released 45 improved potato varieties since 1985. Thirty-four potato varieties, four breeding clones and two advanced selections from NWPVD Program, and six commonly-grown potato varieties were fingerprinted using 32 simple sequence repeat (SSR) markers and 12,808 single nucleotide polymorphism (SNP) markers. Of 32 SSR markers, 29 exhibited significant polymorphism across all the 46 potato clones studied. A total of 143 alleles were observed with an average of 4.6 alleles per SSR marker. These markers span all 12 chromosomes of potato, with a maximum of five markers from chromosome VIII and minimum of one marker from chromosome VI. The polymorphic information content (PIC) and expected heterozygosity (H_e) of the SSR markers ranges between 0.18 to 0.75 and 0.20 to 0.78, respectively. Based on PIC, H_e, and ease of scoring, we recommend a set of eight SSR markers: STG0016, STI0004, STI0012, STI0023, STI0030, STI0033, STM1016 and STM1104 for fingerprinting NWPVD varieties. Out of 12,808 SNPs, 88.8% resulted in reliable three cluster diploid calling of which 87.8% were polymorphic. Tetraploid calling resulted in 44.2% of SNPs of which 94.5% were polymorphic. Our study provided fingerprinting resources for the NWPVD varieties and can be used in issues related to intellectual property rights, ownership, trademark and diversity analysis.  相似文献   

A Case of Congenital Pericardio-peritoneal Communication in a Dog     

James M.  Clinton  V.M.D. 《Veterinary radiology & ultrasound》1967,8(1):57-60

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Etiopathogenesis, clinical manifestations, and management of canine silica urolithiasis     

C A Osborne  C W Clinton  K M Kim  C F Mansfield 《Veterinary Clinics of North America: Small Animal Practice》1986,16(1):185-207

Silica uroliths were first recognized in dogs in the mid 1970s. Currently available data suggest that dietary factors may play a role in their pathogenesis. Diagnosis is facilitated by their typical jackstone appearance but must be verified by quantitative analysis. Surgery is the only feasible method of treatment.  相似文献