Evaluation of Factors Affecting Emergence of Winter Wheat Planted with Seed‐Banded Nitrogen Fertilizers

Abstract

Nitrogen use efficiency by cereal crops may be increased by the placement of fertilizer with the seed; however, high N concentrations often cause injury and reduce both germination and emergence. Two studies were conducted under controlled greenhouse conditions to evaluate factors affecting emergence of winter wheat (Triticum aestivum L.) planted with seed‐banded N fertilizers. Soil from the Ap horizon of a Palouse silt loam (fine‐silty, mixed, mesic Pachic Ultic Haploxeroll) was used in both studies. Two N materials (ammonium nitrate and urea) were banded with the winter wheat seed (‘Stephens’) at N rates of 0, 11, 22, 33, 44, 55, and 66 kg ha−1, and placed in soils at soil matric potentials of −0.15, −0.25, and −0.35 MPa. The tolerance of five winter wheat cultivars ‘Daws’, ‘Hill 81’, ‘Nugaines’, ‘Peck’, and Stephens to sulfur‐coated urea (SCU) materials SCU‐10, SCU‐20, and SCU‐30 was evaluated in a separate study. Nitrogen rates of 0, 50, 100, and 150 kg ha−1 were used at a soil matric potential of −0.20 MPa. In the first study significant N source × water potential (P < 0.0003) and water potential × N rate (P < 0.0001) interactions were observed. In the second study, significant N source × N rate × cultivar (P < 0.0001), N source × N rate (P < 0.0001), and N source × cultivar (P < 0.0001) interactions were found. The N source, N application rate, soil‐water potential, and winter wheat cultivar main effects were all significant for winter wheat emergence. Ammonium nitrate reduced winter wheat emergence 5 to 26% less than urea when comparable quantities of N were placed with the seed. Winter wheat emergence decreased as soil‐water potential decreased (became more negative). These studies demonstrated how the evaluated factors are interrelated with regard to winter wheat emergence. Consequently, guidelines routinely used for seed‐banded N fertilization that only consider N application rate should be modified to also consider N source and soil moisture.

Effect of Seed-Row Placement of Conventional and Polymer-Coated Urea on Winter Wheat Emergence

“…Two of the four varieties in this study experienced significant delays and reductions in overall emergence with increasing PCU rate. Mahler, Lutcher, and Everson (1989) also found differences in final emergence among five winter wheat cultivars sown with SCU fertilizers of different release rates in soil with the same m as that used in this study. All cultivars experienced linear declines in emergence with increasing SCU rate; however, the slope of the decline varied among cultivars and ranged from 3.7 to 5.4 kg N per percentage reduction in emergence (Mahler, Lutcher, and Everson 1989) compared to 6 (for Paladin) or 15 (for Bauermeister) kg N per percentage reduction in emergence with PCU in the present study.…”

“…Seedrow placement of N fertilizer would reduce energy requirements compared to alternative placements (deep band, beside the seed row, or below and beside the seed row) in reducedor no-tillage cereal production systems. However, in-row placement of conventional N fertilizer can inhibit germination and reduce the emergence of cereal crops because of low osmotic potential effects and, in the case of urea-based fertilizers, damage caused by ammonia gas evolution (Severson and Mahler 1988;Bremner and Krogmeier 1989;Mahler, Lutcher, and Everson 1989).…”

Winter wheat response to nitrogen fertilizer form and placement in southern Alberta

“…The major benefit of banding urea versus seed placing urea is that banding separates the seed from the fertilizer, thus decreasing seedling injury from ammonia toxicity and allowing for higher rates of N application. Decreased emergence and crop yield occur frequently when urea is seed-placed under dry seedbed conditions and low seedbed utilization (Mahler et al 1989). Lafond et al (2001) speculated that N banded as urea fertilizer in early fall on Black soils may be lost.…”

Influence of Different Methods and Time of Phosphorus Fertilizer Application in Wheat Under Arid Condition

“…Some contradictory result was found in low P soil, where P was applied in row placement gave better result than that of mixed with seed and broadcasting (Peterson et al, 1981). In another study it was reported that high doses of P fertilizer mixed with seed have a negative effect on germination (Mahler et al, 1989). This negative effect is higher in light textured soils and in conditions where there is limited moisture.…”