Foliar N applications on wheat (Triticum aestivum L.) have increased grain protein. Foliar N timing evaluations have been minimal. The objectives were (i) determine the optimal timing of foliar N for increased grain protein of hard red winter wheat (HRWW) and spring wheat (HRSW), (ii) evaluate effect of foliar N on grain yield, and (iii) determine relationship of grain protein to foliar N application and grain yield. Foliar N was applied at Feekes stage 10.0 (boot) or 10.8 (postpollination) on two cultivars of HRWW and HRSW each year from 1995 to 2000. The foliar N rate (33.7 kg N ha−1) was applied as 1:1 solution of urea ammonium nitrate (UAN) and water. Fertilizer N for a 3360 kg ha−1 grain yield goal was broadcast as UAN after planting. Soil type was Estelline silt loam (fine‐silty over sandy or sandy‐skeletal, mixed, superactive, frigid Calcic Hapludoll). Postpollination foliar N gave the highest grain protein during all years. Grain yield was significantly reduced 5% by boot stage foliar N for HRSW. Neither timing application significantly reduced HRWW grain yield. All wheat data were pooled to relate grain yield level and protein response to foliar N. Grain protein and yield from plots without foliar N were inversely related (r2 = 0.57). Postpollination foliar N increased protein 70% of the time when yield goal was exceeded compared with only 23% when it was not. These results show that postpollination foliar N gave higher grain protein and was most effective when planned yield goal was exceeded.

The effects of nitrogen (N) management systems on Rose and Arapahoe hard red winter wheat (Triticum aestivum L. Emend. Thell.) were measured. Nitrogen fertilizer rates of 0,55,110, and 165 kg N ha -1 were surface broadcast as a full N rate application atpreplant or were split-applied as two half N rates applied in the fall and spring. Supplemental N was also applied as a foliar spray treatment after anthesis at either 0 kg N ha -1 or 33 kg N ha -1 as a diluted urea-ammonium nitrate solution. The grain yield of Arapahoe was generally higher than Rose across treatments, but protein was slightly lower. Splitting the N application lowered yield somewhat in both varieties compared to the entire N rate applied at preplant, but grain protein increased by nearly 0.8% with the split application over the preplant application. Grain protein also increased up to 1.6% with a late season foliar N application despite some leaf damage compared to no foliar N. Grain yield was correlated to many agronomic parameters measured throughout the growing season, but grain protein was correlated only to shoot N concentration in samples harvested at the soft dough stage (Feekes stage 11.2).

et al., 1990; Stark and Tindall, 1992; Wuest and Cassman, 1992;Knowles et al., 1994). Other researchers have mea-Foliar N applications on wheat (Triticum aestivum L.) have insured increases in grain protein concentration from apcreased grain protein. Foliar N timing evaluations have been minimal.plications of late-season N either as foliar sprays or dryThe objectives were (i) determine the optimal timing of foliar N for increased grain protein of hard red winter wheat (HRWW) and spring topdress fertilizers even though early-season N applicawheat (HRSW), (ii) evaluate effect of foliar N on grain yield, and tions were more than sufficient for potential grain yield (iii) determine relationship of grain protein to foliar N application (Pushman and Bingham, 1976; Westcott, 1998). and grain yield. Foliar N was applied at Feekes stage 10.0 (boot) or Research reports investigating the influence of foliar-10.8 (postpollination) on two cultivars of HRWW and HRSW each applied N on wheat grain protein concentration are not year from 1995 to 2000. The foliar N rate (33.7 kg N ha Ϫ1 ) was applied Plant Sci. Dep., South Dakota State Univ., Box 2207A, Brookings, quired nutrient recommendations for N, P, K, and Cl for a SD 57007. Received 13 Dec. 2001. *Corresponding author (anthony_ bly@sdstate.edu).Abbreviations: HRSW, hard red spring wheat; HRWW, hard red winter wheat; UAN, urea ammonium nitrate. Published in Agron.

High pH, electrical conductivity (E.C.), and extractable Na levels in the residue remaining after aluminum was extracted from bauxite were greater than can support vigorous plant growth. These caustic properties must be ameliorated so that vegetation could be established on the surface of large disposal ponds. Fresh residue was added to 14 field lysimeters of dimensions 3 m long x 3 m wide x 1 m deep. Internal drainage was enhanced in some lysimeters and restricted in others. Gypsum applied at the rate of 7.5% of the weight of the top 15 cm of residue in selected lysimeters. These management issues were studied to determine how their influence would lower chemical properties to support vegetation. Residue samples were removed annually for 5 years after the lysimeters were established to determine changes in pH, E.C., and extractable Na and Al over time. Plant species C. dactylon (bermudagrass), Atriplex nummalari (oldman saltbush), and Atriplex canescens (fourwing saltbush) were planted either as seeds or transplants beginning the third year after lysimeter establishment. Residue pH, E.C. Na, and Al decreased annually, but more gradually in restricted drainage. Species survival in the enhanced drainage treatments was more vigorous with gypsum amendments beginning in the third year after lysimeter establishment. This coincided with a decrease in the mean pH below 9.5 and decrease in mean E.C. below 10 dS/m. Extractable Na and Al did not seem to influence survivability. Survival of seeded and transplanted C. dactylon was greater than the two Atriplex spp. each year. This study proved that the caustic properties of this residue could be lowered enough to support vegetation, but not without appropriate drainage. The addition of gypsum amendments and appropriate amounts of supplemental water would accelerate the timeframe for vegetation establishment probably at a level commensurate with the application rate of both inputs in a well-drained system.

No abstract