Recovery of nicotine-free proteins from tobacco leaves using phosphate buffer system under controlled conditions.

Establishment of an effective, high-throughput processing system to recover protein from tobacco with no nicotine contamination is essential and vital to the development of value-added, alternative applications for tobacco farmers. We have successfully developed a mechanism capable of processing up to 60 kg of tobacco leaves per hour with phosphate buffer (Na(2)HPO(4)-KH(2)PO(4)) simultaneously added to stabilize the protein as the plant was being disintegrated. The optimal processing parameters were identified, including the ratio of buffer to leaf (BLR) at 4.75 (w/w), buffer pH 7.85, and buffer concentration 0.085 mol/L, achieving a maximum yield of soluble protein at 12.85 mg/g fresh leaf. Acetone at -20 degrees C was the most effective among all methods investigated to remove nicotine from protein; however, it also drastically reduced the recovery rate of protein (63.3%). Ultrafiltration was only able to remove about 50% of the residual nicotine, although the protein recovery rate was high (94.7%). The residual nicotine content inherent in the recovered protein was completely removed by rinsing the protein with 85% phosphoric acid at pH 3.5 for three times with a protein recovery of 94.5%. The pilot-scale operation provides a solid foundation for further scale-up to industrial production of nicotine-free tobacco protein that could bring added value to tobacco for nonsmoking applications.

Cropping systems for phytoremediation of phosphorus-enriched soils.

Eutrophication of freshwater bodies is frequently attributed to elevated phosphorus (P) concentrations in surface runoff from P-enriched agricultural soils. Forage and grain-cropping systems were compared for their effectiveness at remediating P-enriched soils. At each of four locations, one of three forage systems (Forage I = cereal rye silage and corn silage annually; Forage II = alfalfa; Forage III = annual ryegrass and corn silage annually) and the grain system (corn, small grain, and soybean rotation) were maintained for 3 yr on soils with five distinct initial soil P concentrations that were established by using four annual applications (1994-1997) of five different rates (0, 100, 200, 300, and 400 kg total P ha(-1) y(-1)) of poultry manure, dairy manure, or commercial fertilizer. Across all manure P treatments at all locations, the forage systems had greater removal of P than the grain system. Soil P concentration changes (2001-2004) did not reflect differences in crop P removal. Few significant reductions in soil P concentration were observed for either crop system. When reductions did occur, they were for the more highly enriched soil P treatments. No significant reductions in soil P concentration have occurred for the lowest manure P treatments. Considerable variability in crop P concentrations was observed among species at locations and among years produced. However, crop P concentrations did increase uniformly as soil P concentration increased, indicating that luxury consumption of P does occur in agronomic species produced on P-enriched soils.

Root-Knot and Root-Lesion Nematode Suppression by Cover Crops, Poultry Litter, and Poultry Litter Compost.

Experiments using soil-incorporated cover crops and amendments of poultry litter (PL) and PL compost to suppress root-knot (RKN) and root-lesion nematodes were conducted in response to increasing nematode populations in Maryland's potato production areas. Identical experiments were established in microplots infested with Meloidogyne incognita or Pratylenchus penetrans. Treatments consisted of 12 3-year rotational sequences comprising potato (year 1) and cucumber (year 2) followed by a moderately RKN-resistant or susceptible soybean cultivar, castor bean, grain sorghum, or sorghum sudangrass; PL or PL compost were amended to some of the RKN-susceptible soybean and sorghum sudangrass plots. In the third year of the rotation, potato followed by soybean was planted in all 12 treatments. The RKN-resistant soybean, castor bean, sorghum sudangrass, and fallow or tillage decreased the populations of M. incognita compared with microplots where RKN-susceptible soybean had been grown. However, RKN populations quickly recovered. Root-lesion nematode was reduced in the spring of 2001 following application of high rates of PL and PL compost in 2000. In the fall of 2001, sorghum sudangrass alone or in combination with PL or PL compost, grain sorghum, or fallow or tillage reduced root-lesion nematodes compared with either soybean cultivar. No treatment affected root-lesion nematode the following year. The use of cover crops and PL compost is an effective method to reduce nematode populations only if successively incorporated into rotational cropping sequences.

Verification of a European corn borer (Lepidoptera: Crambidae) loss equation in the major corn production region of the northeastern United States.

Field studies in Pennsylvania and Maryland were conducted during 2000, 2001, and 2002 to test the applicability of published yield loss relationships developed in central Pennsylvania for European corn borer, Ostrinia nubilalis (Hübner), management in warmer, longer season corn, Zea mays L., grain production regions of the northeastern United States. Both isoline hybrids and non-Bt lead hybrids were compared against Bacillus thuringiensis (Bt) hybrids to measure effects of the pest on yield. The European corn borer economic analysis model was used to make site-specific predictions of loss per European corn borer larva for comparison with measured yield loss per larva. Although the model did not predict loss per larva at a field level, it did predict loss at a regional level. The model predicted an overall percentage of yield loss per larva of 2.69+/-0.12% over the region, which was similar to the measured yield loss per larva of 2.66+/-0.59% for isoline hybrids and 3.08+/-0.51% for lead hybrids. The model, on average, provided a good prediction of percentage of yield loss per larva within the climatic zones of 1100-1700 degree-days (DD) (base threshold 12.5 degrees C). Our results suggest that the yield loss relationship developed in Central Pennsylvania, when matched to the timing of third instar second generation European corn borer stalk tunneling is adequate for major corn grain production zones of the northeast United States.