production, making the production in short rotation sustainable. The biomass element that determines the energy released during oxidation is carbon (C). Biomass C content is usually 45% to 50% (by oven-dried mass) ( Schlesinger, 1991 ), but it may vary
( Keightley, 2011 ). Carbon sequestration has become increasingly important in light of climate change and the ability to estimate the C stock of agricultural land could be important for gauging offsets to C emissions. The objective of this study was to
Plastic mulch is commonly used by commercial producers of cucurbits because it increases soil temperature, reduces weed pressure, retains soil moisture, and increases earliness of harvest ( Lamont, 2005 ). Compared with bare ground systems, black
Texture and color are the main quality attributes of black table olives ( De Castro et al., 2007 ). Mafra et al. (2007) reported that the stage of ripening of olive fruit is determinant for a final product with adequate firm texture because
manually until a uniform column formed. Each tube was placed in a black PVC sleeve with a bottom cap drilled with holes for drainage. Sod pieces (10 cm in diameter) of seashore paspalum ( Paspalum vaginatum Swartz) cultivars Salam, Excalibur, and Adalayd
Bean common mosaic necrosis virus (BCMNV) includes four African strains, BCMNV-NL3, -NL-5, -NL8, and -TN1, previously considered to be members of the bean common mosaic virus (BCMV) group. Many bean cultivars resistant to BCMNV-NL8 were found to be susceptible to the other strains of the virus. `California Light Red Kidney' (CLRK) and `Carbon', resistant to BCMNV-NL8, were crossed with the susceptible cultivars Sanilac or Black Turtle 2 (BT-2). In plants of F1, F2, and reciprocal backcross populations involving CLRK × `Sanilac' or BT-2 × `Carbon', the resistance to BCMVN-NL8 was determined to be conferred by a single dominant factor. The same factor was detected in BCMNV-NL8-resistant `Great Northern 1140' and `IVT-7214, when crossed with the susceptible cultivar Stringless Refugee or BT-2.
Biological production of sulfide (S2-) in soil has been reported to depend on system redox potential and on the concentrations of available sulfate (
Biodegradable mulches made from kraft paper coated with polymerized (cured) vegetable oils were compared to black polyethylene mulches for promoting the growth of watermelon in northern Florida. Data from three spring growing seasons have been collected. Yields of watermelon planted on paper-soy oil and paper-linseed oil mulches were similar to those obtained for the control polyethylene mulches. This was the case where the paper-oil was cured before field application as well as when the paper-oil was applied to the field wet and curing took place in situ. Paper-oil mulches containing carbon black effectively blocked nutsedge growth, while nutsedge pierced and grew through the black polyethylene mulch. Degradation of the buried tucks were more rapid initially for paper-soy oil than paper-linseed oil mulch, but both lasted long enough to hold the mulch in place until spring harvests (≈2.5 months). In conclusion, paper coated with polymerized vegetable oil appears to be an effective substitute for polyethylene mulch for growing watermelon in Florida, although drawbacks include messiness in handling oily paper, slower application speeds, higher initial costs than polyethylene, and variability in rates of curing and degradation depending on soil and weather conditions.
Carbon dioxide concentrations measured within and above a strawberry plant (Fragaria × ananassa) canopy were significantly higher during enrichment with carbonated water or 900 kg CO2 ha-1 hr-1 applied as gas. Both sources were applied to the base of the plants through drip irrigation tubing under a black polyethylene mulch (0.025 mm) covering or over bare unmulched soil. Mulch affected the concentrations at the top of the strawberry canopy differently for the two sources of CO2 enrichment. Carbonated water was found to reduce the pH of the calcareous soil at the research site (pH 8.2) during and between irrigations. The greatest single pH reduction was 2.6 pH units during irrigation measured in mulched soil; significant soil pH reductions were detected as long as 28 days after irrigation underneath the mulch. Soil pH “duration” below pH 7.4 was 70% greater considering mulch and carbonated water vs. no mulch and carbonated water irrigation.
Leaf blackening of Protea neriifolia is a common postharvest problem which renders flowers unsalable. Previous reports suggest that depletion of carbohydrates in source leaves caused by transfer of carbohydrates to the strong flower sink may be a major cause. Flowering stems of P. neriifolia were harvested in California under standard conditions and shipped to Baton Rouge, La. Upon arrival, the stems were re-cut (1 cm.), the number of leaves counted and the diameter and height of the flowers measured. Stems were transferred to 1 liter deionized distilled water containing 50 ppm hypochlorite, and 0.5% sucrose or no sucrose, and placed in a growth chamber (25°C) either with 12 hrs light (120 μmol/m2/s), or 24 hrs darkness. Number of leaves 10% black, flower diameter and height, and carbon exchange rates were measured every two days over a 16 day interval. Soluble and insoluble nonstructural carbohydrates were determined and assimilate export rate was estimated for each sampling day. Stems placed in the light maintained healthy foliage while those in the dark had 77-l00% of their leaves 10% black by day 8. Flower and leaf quality in the fight treatment were superior with addition of sucrose to the vase solution. Influence of treatments on carbohydrate metabolism in relation to leaf blackening and flower development will be discussed.