Effect of Fertilizer Phosphorus Placement Depth on Winter Wheat Yield

Abstract

Field studies were conducted with winter wheat (Triticum aestivum L. ‘Centurk 78’) at nine locations in southwestern, central, and eastern Nebraska in 1982 and 1983 to determine the effect of phosphorus (P) placement depth (0, 5, 10, and 15 cm). As a comparison to these depths, seed placed P, soil surface placed P, and no P treatments were used. A rate of 11 kg P ha−1 was applied. Soil great groups were either Argiustolls or Argiudolls with surface soil Bray and Kurtz no. 1 P levels ranging from 4 to 9 mg kg−1 and pH values ranging from 5.5 to 7.5. Grain yield was increased by added P in both years though magnitude of response varied at different locations. A linear and quadratic response to depth was evident in both years, though variation occurred between locations. Optium depths of P placement for maximum grain yield occurred at 11.9 cm in 1982 and 10.4 cm in 1983. No differences between either the best depth (10 cm) and seed treatments or the surface and seed treatments were found, indicating that, depending on management situations, these methods of P application could be used interchangeably. Total P uptake was increased by P applications in a manner similar to grain yield. Phosphorus uptake of the seed treatment and the best depth treatment at several growth stages (Feekes' stages 2.0, 6.0, 10.0, 10.5, and 11.4) was compared. An early advantage (stage 2.0) of the seed treatment was not evident at harvest, indicating that early P uptake is not necessary for maximum yield. The number of heads and seed weight were both increased due to applied P in both years and seed weight responded linearly to depth in 1982. No effect on the seed number per head was found.

Managing Acute Phosphorus Loss with Fertilizer Source and Placement: Proof of Concept

“…Corn (Zea mays L.) P uptake from below 15 cm has been shown to be greater than P uptake from the 0-to 15-cm layer (Murdock and Engelbert, 1958). Wheat (Triticum aestivum L.) yield was shown to improve with P placed in the subsoil, with maximum yield occurring at roughly 10 cm below the soil surface (McConnell et al, 1986). They further showed that placement of P was critical to early uptake; however, early uptake of P was not critical to yield.…”

Managing acute phosphorus loss with fertilizer source and placement

“…Corn P uptake from below 6 inches has been shown to be greater than P uptake from the 0‐ to 6‐inch layer (Murdock and Engelbert, 1958). Wheat yield was shown to improve with P placed in the subsoil, with maximum yield occurring at roughly 4 inches below the soil surface (McConnell et al, 1986). They further showed that placement of P was critical to early uptake; however, early uptake of P was not critical to yield.…”

How changing root system architecture can help tackle a reduction in soil phosphate (P) levels for better plant P acquisition

“…This also matches observations of root proliferation in topsoils (0–30 cm) when fertilizers are strategically placed (McConnell et al . ). The exponential branching distribution ( G , the number of roots per cm) is described by where two variables define the branching structure, A (cm −1 ) denotes the maximum density distribution (i.e.…”