Nutrient source and tillage influences on nitrogen availability in a Southern Piedmont corn cropping system

Poultry (Gallus gallus domesticus L.) litter (PL) is a readily available nutrient source for crop production in the Southeast USA. Long-term PL application may alter availability of N and the effect may be dependent on tillage practice. Tillage [no till (NT) vs. conventional (CT)] and N source (PL vs. commercial fertilizer CF) effects on N availability and plant uptake were evaluated in years 9, 10, and 11 of a long-term cropping systems study at the United States Department of Agriculture, Agricultural Research Service, J. Phil Campbell Sr. Natural Resource Conservation Center, Watkinsville, GA, USA. Mineral N in the top 10 cm, measured in situ, varied each year and was influenced by time, tillage, and N source. In 2003 (year 9), soil mineral N content was greater in CT–CF (100 kg ha⁻¹) than in NT–PL (95 kg ha⁻¹) but in 2004 (year 10) and 2005 (year 11) it was lower in CT–CF (93 and 60 kg ha⁻¹) compared to NT–PL (140 and 71 kg ha⁻¹). Nitrogen mineralization rates were generally greater for PL than for CF treatments with the difference being almost 1 kg ha⁻¹ day⁻¹ in 2003. Mineralization rates were greater for NT–PL compared to CT–CF in 2004 and 2005. Across the three growing seasons, corn (Zea mays L.) aboveground biomass was consistently greater in the NT–PL treatment than in the NT–CF and CT–CF treatments. Correlation between aboveground biomass and N mineralization was greater for PL than for CF (0.75 vs. 0.48). Patterns of N mineralization and total soil mineral N indicated that the distribution of N through the growing season more closely matched corn N demand in PL treatments. Results indicate that improved N availability through the growing season, by combining NT and PL, can result in more profitable corn production in the southeast.     

Nutrient uptake and yield of sweet pepper as affected by stage of development and N form

Uptake of NO₃ ^‐, NH₄ ⁺, P, K⁺⁺, Ca⁺⁺ and Mg⁺⁺, as influenced by the stage of plant development and three NO₃ ^‐: NH₄ ⁺ ratios (1: 0, 1: 1, and 0: 1), was determined for sweet pepper (Capsicum annuum L. cv. ‘California Wonder'). Uptake was highest during fruit development and immediately after fruit harvest, indicating that fruit removal promotes nutrient uptake. When NO₃ ^‐ and NH₄ ⁺ were supplied in equal concentrations, NO₃ ^‐ was absorbed more readily. Each increment in NH₄ ⁺ decreased the uptake of K⁺, Ca⁺⁺, and Mg⁺⁺ by fruit tissue, while no significant effect on the N and P content of the fruit was observed. Ammonium nutrition reduced plant dry weight and fruit yield in comparison to NO₃ ^‐. Results from this study suggest that NO₃ ^‐ is the preferred N form, and that fertilizer application should be scheduled according to specific physiological stages to maximize nutrient uptake. Nutrient content of vegetative tissue was not indicative of potential yield.     

Effect of N‐form on growth and nutrient content of creeping bentgrass 1

Abstract

The primary nitrogen forms utilized by plants are ammonium and nitrate. Although the importance of nutrients other than nitrogen for proper turfgrass growth is well established, the amounts of these nutrients in the plant tissue in relation to the use of different N‐forms has not been clearly documented. This study was conducted under greenhouse conditions to determine the effect of N‐form and cutting regime on growth, macronutrient, and micronutrient content of creeping bentgrass (Agrostis palustris Huds. ‘Penncross'). Treatments consisted of 100% NO3^? (calcium nitrate), 100% NH₄ ⁺ (ammonium sulfate), and a 50:50 ratio of NH₄ ⁺:NO₃ ^?. Half the turfgrass plants were maintained at a height of 1 cm (cut), while the other half of the plants were not cut until the end of the study (uncut). The uncut 50:50 treatment yielded the highest shoot, verdure, and total plant dry matter, while the uncut NO₃ ^? treatment produced the highest root dry matter. The uncut NH₄ ⁺ treatment yielded the least shoot, root, and total plant dry matter. Plants of the uncut NO₃ ^? treatment had greater accumulation of macronutrients in the shoot and root tissue compared to plants of the NH₄ ⁺ treatment. The uncut NO₃ ^? and 50:50 treatments had higher total accumulation of micronutrients compared to the uncut NH₄ ⁺‐treated plants. The cut NO₃ ^? treatment resulted in the highest macronutrient and micronutrient contents in the root tissue in comparison to other cut treatments. The cut treatments had the highest percentage accumulation of nutrients in the verdure tissue, while the uncut treatments had the highest percentage accumulation of nutrients in the shoot tissue.     

Effect of nitrogen form during the flowering period on zucchini squash growth and nutrient element uptake

Zucchini squash (Cucurbita pepo L. cv. Green Magic) plants were grown hydroponically with nitrate (NO₃):ammonium (NH₄) ratio of 3:1 until the onset of flowering when the plants were assigned to four NO₃:NH₄ ratio (1:0, 1:1, 1:3, or 3:1) treatments. Changing the original nitrogen (N) form ratio significantly affected plant growth, fruit yield, nutrient element, and water uptake. Growth of plants was better when NO₃‐N (1:0) was the sole form of N than when NH₄‐N was part of the N treatment. Fruit yields for plants fertilized with 1:0 or 1:3 N‐form ratio were double those of plants grown continuously with 3:1 N ratio. The largest leaf area and plant water use were obtained with 1:0 N ratio treatment Total uptake of calcium (Ca), magnesium (Mg), and potassium (K) decreased with increasing NH₄‐N proportion in the nutrient solution which suggest NH₄‐N was competing with these cations for uptake. The results also demonstrated that growers may increase fruit yield by using a predominantly NO₃‐N source fertilizer through the vegetative growth stage and by shifting the NO₃:NH₄ ratio during the reproductive phase.     

Nutrient accumulation in leaf tissue of rapid‐cycling brassuca oleracea responds to increasing sodium selenate concentrations

Brassica oleracea L. are important economic vegetables, and are capable of selenium (Se) enrichment to enhance human nutrition and health. Because Se enrichment may influence the nutrient balance of this crop, a study was done to test the effects of selenate‐Se on plant nutrients. Plants of a rapid‐cycling B. oleracea population were grown in nutrient solutions amended with Na₂SeO₄at 0.0, 3.0, 6.0, and 9.0 mg L^‐1. Leaf tissue was then analyzed for nutrient content. Boron (B) (P=0.01), iron (Fe) (P=0.01), and phosphorus (P) (P=0.01) content decreased, while Se (P=0.01), sulfur (S) (P=0.01), and potassium (K) content (P=0.01) increased with increasing selenate‐Se treatments. Significant quadratic responses were found for magnesium (P=0.01) and molybdenum (P=0.01). No significant differences in leaf fresh or dry weight were detected. Changes in plant nutrient content can be expected when Brassicas are enhanced for delivery of beneficial organic Se.     

A rapid method for the quantification of steroidal glycoalkaloids by reversed phase HPLC

Summary Methods were developed for clean-up of potato tuber extracts on solid phase extraction CN-cartridges and for analysis of steroidal glycoalkaloids by reversed phase HPLC. The alkaloids α-solanine, α-chaconine, α-solasonine and α-solamargine could be separated on C₈ or C₁₈ reversed phase columns using a mobile phase of acetonitrile/Tris-buffer (3∶2, v/v). The analysis time of tuber extracts containing these alkaloids was less then 4 min, if the pH of the mobile phase was adjusted to 7.4 and run at a flow rate of 0.5 ml/min.     

Single nucleotide polymorphism discovery of Pinus radiata with chromosome walking PCR method

In this paper, the basic principle of chromosome walking is presented and we used an actin gene of radiata pine (Pinus radiata) as an example to conduct upstream and downstream chromosome walking for EST sequences. The full genomic sequence (2154 bp) of the actin gene, including promoters 5′ UTR, CDS and 3′ UTR, was identified by chromosome walking. PCR amplification and DNA band sequencing from 200 unrelated radiata pine trees revealed a total of 21 SNPs for the actin gene, three in the promoter region, 15 in CDS and 4 in 3′ UTR. The results of this experiment provide a technical framework for SNPs discovery in none coding regions of candidate genes. __________ Translated from Acta Botanica Boreali-Occidentalia Sinica, 2007, 27 (8): 1571–1576 [译自: 西北植物学报]     

Gene for broad, contiguous dark stripes in cocozelle squash (Cucurbita pepo)

Alternating intense (dark) and light stripes on the fruits are a fairly common feature of Cucurbita pepo, a highly variable species encompassing various kinds of pumpkins, squash, and gourds. The intense stripes can be narrow and broken or broad and contiguous. Narrow, broken intense striping is conferred by allele l-1 ^St, which is dominant to allele l-1 for non-striped, lightly colored fruits and recessive to allele L-1 for non-striped, intensely colored fruits. Cocozelle-type squash often exhibit broad, contiguous intense stripes. The inheritance of this characteristic was studied by transferring it from cocozelle squash and preparing nearly isogenic lines having broad-striped, narrow-striped, and non-striped light-colored fruits. In the broad-striped near-isogenic line, the intense stripes averaged 37% wider than in its narrow-striped counterpart. The broad-striped line was crossed with the narrow-striped line, the non-striped light-colored line, and the non-striped intense-colored `Fordhook Zucchini'. Broad striping was dominant to narrow striping and to non-striped light and conferred by a single gene; it was recessive to non-striped intense. The gene for broad striping was found to be allelic to that for narrow striping and to that for non-stripe dintense and is herein assigned the symbol l-1 ^BSt. Dominance relationships at the l-1 locus were observed to be L-1>l-1 ^BSt >l-1 ^St >l-1. This revised version was published online in July 2006 with corrections to the Cover Date.