Valtcho D. Zheljazkov

Application of high Cu compost to Swiss chard and basil

A greenhouse container experiment was conducted to evaluate the effect of high Cu compost on basil and Swiss chard productivity, and the accumulation of As, Ca, Fe, Hg, K, Mg, Na, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, S and Se in growth medium and plant tissue. The Cu content of the compost was over 1200 mg/kg, much higher than Canadian standards for type B compost quality. The treatments consisted of control soil (0% compost), and 20, 40 and 60% (by volume) of high Cu compost added to soil. All compost application treatments (20, 40 and 60%) resulted in increased dry matter yields in Swiss chard and basil. Addition of high Cu compost influenced basil plant development. Plants from the 20 and 40% treatments had higher numbers of buds and flowers. There were no differences between the control and 60% compost treatments with respect to flower initiation. Addition of 20, 40 and 60% compost to the soil resulted in increased EXCH fractions of Cu, but not of Mn and Zn. Compost additions resulted in increase in the HNO(3) extractable, CARB, FeMnOX, and in OM fractions of Cu, Mn and Zn in soils. Compost application increased soil pH and EC, soil HNO(3) extractable Ca, K, Mg, P, Na, B and Pb, but did not alter soil HNO(3) extractable Cd, Co, Cr, Mo, Ni, Se. Increased rates of compost application decreased tissue Ca in basil, tissue Na in both plants, increased tissue K, Mg in both plants, but, did not alter tissue P, Co, Cr, Mo, Ni of either plants, and B in basil. Tissue As, Hg, Pb, and Se from all treatments were under the detection limits of VGA-AAS (for As, Hg, Se) and ICP (for Pb). Compost additions altered basil oil chemical composition. Copper in the essential oil of basil was below 0.25 mg/l. In conclusion, the addition of high rates of relatively immature high Cu compost may not always increase Cu concentration in plants and in plant oils.

Comparison of Three Digestion Methods For the Recovery of 17 Plant Essential Nutrients And Trace Elements from Six Composts

A comparative investigation for recovery of 17 elements by using three digestion methods (nitric acid, nitric/perchloric acid and dry ashing) in six mature composts was conducted. The elements measured were Ca, Fe, K, Mg, Na, As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se and Zn. Two of the composts were prepared from mixtures of racetrack manure and sewage sludge. Another compost was developed from a mixture of food waste and straw with the addition of nitrogen fertilizer. The remaining three were MSW (municipal solid waste) composts from the Lunenburg Regional Recycling and Composting Facility, Nova Scotia, prepared in 1995, 1996 and 1997, matured, and used in the subsequent year. There were no significant differences between the three digestion procedures in the recovery of Ca, K, Na, and Hg. HNO3 digestion provided the highest recovery of As, Mo, Ni and Se, HNO3/HClO4 provided the highest recovery of Co, while dry ashing provided the highest recovery of Mn. For Cd and Pb, both HNO3 and HNO3/HClO4 provided similar and better recovery than dry ashing. For Cr, higher values were obtained by using dry ashing or HNO3/HClO4 digestion, while for Mg, HNO3 and dry ashing provided similar and better recovery than the HNO3/HClO4 digestion procedure. For Cu and Zn, HNO3 was superior to HNO3/HClO4 digestion, while dry ashing was not significantly different from the other two procedures. For Fe, dry ashing provided better recovery than HNO3. Element recovery depended not only on the digestion procedure, but also on the type of compost. Overnight presoaking of the compost samples in concentrated nitric acid at room temperature prior to heating did not improve the element recovery. The results show that when comparing the three methods, nitric acid digestion is sufficient for the recovery of the greatest number of elements in various composts.

Aromatic plant production on metal contaminated soils.

Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha(-1) for Cd, 660 g ha(-1) for Pb, 180 g ha(-1) for Cu, 350 g ha(-1) for Mn, and 205 g ha(-1) for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (<1 microm) particles, although there were larger particles (1-5 microm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

Wool-waste as organic nutrient source for container-grown plants.

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO(3)-N and NH(4)-N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.

Influence of seeding date and harvest stage on yields and essential oil composition of three cultivars of dill (Anethum graveolens L.) grown in Nova Scotia

Experiments were conducted in two locations in Nova Scotia, Canning and Truro, during 2001 and 2002 to determine the effect of seeding date and harvest stage on productivity and composition of essential oil from Anethum graveolens L. ‘Mesten, Dukat’ and ‘Hercules’. Delayed seeding generally reduced yields and altered the concentration of some essential oil components. Both dill seed and dill weed oil from this study had compositions similar to commercially available oil and reported dill oil compositions. The seed oil had moderate to high carvone content (17.9–64.0%) as is desired for the international market. Carvone content in oil increased as the plants matured. Lower yields and essential oil yields were obtained from cv. Hercules compared with the other two cultivars. Herbage yields and essential oil content were typical for the plant species; seed yields were below average, but there is potential to increase these yields through different seeding dates, harvest dates and investigation into optimum nu...

Effect of distillation waste water and plant hormones on spearmint growth and composition

BACKGROUNDnDistillation waste water (DWW) is a by-product from steam distillation of essential-oil crops; and currently, it is discharged into streams and rivers. The effects of DWW from 13 essential-oil crops, extracts from two alkaloid-containing species, and three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) were evaluated on productivity, essential-oil content and composition of spearmint (Mentha spicata L.) cv. Native.nnnRESULTSnSpearmint plant height was increased by the application of GA3 and Melissa officinalis DWW but suppressed by the application of Rosmarinus officinalis and Tagetes lucida DWW. Generally, MJ, GA3 and M. officinalis and Mentha arvensis DWW increased dry yields. The concentration of L-carvone in the oil ranged from 550 g kg(-1) (with Monarda citriodora DWW) to 670 g kg(-1) (with T. lucida DWW). M. citriodora DWW reduced the concentration of L-carvone in the oil by 23% relative to the control.nnnCONCLUSIONnResults suggest that DWW from essential-oil crops may affect monoterpene synthesis in M. spicata and, hence, may have a direct effect on the essential oil composition. DWW from essential-oil crops may be used as a growth promoter and modifier of the essential oil composition of spearmint.

Comparison of Five Digestion Procedures for Recovery of Nutrients and Trace Elements in Plant Tissue

ABSTRACT Comparison of five digestion procedures for recovery of nutrients and trace elements in plant tissue were examined. The objectives of this study were to compare five digestion procedures: AOAC (dry ashing), two nitric acid, (NA1, commonly used and NA2, our modification), and two aqua regia (AR1, commonly used and AR2, our modification) procedures for recovery of 15 plant nutrients and trace elements in corn, swiss chard, thorn apple, and barley flour (certified material). Generally, the recovery of various elements depended on the digestion procedure used and the plant species. In most instances, NA2 recovered more phosphorus (P), potassium (K), sulfur (S), and manganese (Mn) than the AOAC or the two AR procedures. Also, overall NA2 recovered more K and magnesium (Mg) than NA1. Extractants AR1 and AR2 recovered more iron (Fe) than the two NA procedures, and the same as the AOAC. The AR2 recovered very similar concentrations of nutrients as the AOAC; and in corn tissue, AR2 recovered more zinc (Zn), chromium (Cr), nickel (Ni), copper (Cu), and boron (B) than the AOAC. The AOAC recovered less S and B than the other procedures tested. For instance, in barley flour, AOAC recovered eight to nine times less S, while in corn tissue AOAC recovered around three times less S than the NA procedures. Overall, there are three important findings: (1) NA procedures may be used for recovery of most elements in plant tissue; (2) AR2 procedure is comparable to the official AOAC method for recovery of nutrients and trace elements in plant tissue, and (3) the official AOAC method used in Canadian plant testing laboratories may underestimate the concentration of S and B in plant tissue.

EFFECT OF PLANTING DATE, NITROGEN RATE, AND HYBRID ON SUNFLOWER

Sunflower is a potential crop for the southeastern United States for production of cooking oil or biodiesel. In 2007, we evaluated the effect of planting date (PD, 20 April, 20 May, and 20 June), nitrogen (N) application rate (0, 67, 134, and 202 kg ha−1), and hybrid (‘DKF3875’, ‘DKF2990’, ‘DKF3510’, and ‘DKF3901’) on sunflower productivity and oil profile in four Mississippi locations, Newton, Starkville, and two sites in Verona. There was a trend of increased oleic acid concentration with earlier planting dates, especially in hybrids with lower oleic acid concentration. Earlier planting dates of ‘DKF3901’ and ‘DKF2990’ (the hybrid with the lowest oleic acid) actually had 200 to 300 g kg−1 higher concentration of oleic acid when grown in Mississippi vs. the original seed of the same hybrids used for planting and produced at a more northern latitude. This and a recent study in Mississippi suggest that modern hybrids could provide ample yields even when the N fertilization is relatively low.

Reduction in phosphorus availability in poultry and diary manure by mineral amendments

Abstract Phosphorus (P) loading of soils from the repeated application of manure and the associated loss of P to water systems is a serious and increasing problem in todays agricultural landscape. The hypothesis of this study was that the application of mineral amendments to manure might reduce P availability in manure and soil without affecting crop productivity. An incubation experiment was conducted to evaluate the ability of aluminum sulfate, ferric chloride or calcium hydroxide at 100 and 200 g kg−1 of manure to reduce phytoavailable (Mehlich-3 extractable) P in liquid dairy, laying hen and broiler chicken manure. Mehlich-3 extractable P was reduced from 59 to 97% in all manure treated with aluminum sulfate and ferric chloride. The calcium hydroxide treatment resulted in a Mehlich-3 extractable P reduction ranging from −17 to 51%. A container experiment was then carried out to examine the effect of soil with pre-treated manure on timothy (Phelum pretense L.) growth and soil P levels. Timothy yields in all dairy manure treatments were 45–57% lower compared to an N–P–K control, but were not lower compared to the untreated manure control. Dairy manure + aluminum sulfate (200 g kg−1) reduced water-extractable P by 82% relative to the N–P–K control. All other manure and amendment treatment combinations were not statistically different from the N–P–K or the untreated soil controls in terms of water-extractable P, Mehlich-3 extractable P or grass yield. Significant reductions in Mehlich-3 extractable P were observed with the aluminum sulfate or ferric chloride amendments, while varied results were observed with the calcium hydroxide amendment. Results suggest that the use of manure amended with aluminum sulfate or ferric chloride has little effect on growth or P accumulation by timothy. Overall, this study demonstrated that mineral pre-treatment of manure can reduce the extractable P content of the manure and soil without negative effects on plant growth.