Effect of Broadcast versus Banded Phosphorus Application on Fate of Applied P in Soil and in Snowmelt Water Flow
IPNI-2014-CAN-4RC07
01 Apr 2014
Project Description
Objective:
To determine the fate of phosphorus (P) applied as broadcast versus banded application method to a prairie soil. The agronomic and environmental benefits of a key aspect of 4R Nutrient Stewardship, right fertilizer placement, will be revealed in this research. Timing of application and the effect of rate of applied phosphorus is also covered. Information developed from the project will be used to promote the phosphorus fertilizer placement strategy that contributes to enhanced crop utilization of applied fertilizer P and reduced losses of Pin surface run-off water. Specifically, the fate of phosphorus following application will be determined through a series of chemical and spectroscopic P speciation techniques applied to soil and water. Soil phosphorus fractions in soil, and phosphorus forms and content in snowmelt run-off water will be assessed as a function of phosphorus fertilizer placement.
2014-2015 Workplan:
A farm field will be selected in the Dark Brown soil zone of southern Saskatchewan to represent a typical undulating cropped prairie landscape. A replicated experiment will be set up with spring applied treatments that include 1) no P fertilizer, 2) P fertilizer added at recommended rate (20 kg P205/ha) placed with the seed at seeding time in spring, 3) P fertilizer at recommended rate (20 kg/ha) banded at 10 em depth prior to seeding, 4) P fertilizer applied at recommended rate (20 kg/ha) as a broadcast application with incorporation, 5) P fertilizer applied as broadcast fertilizer without incorporation at 20 kg/ha, 6) P fertilizer applied as broadcast fertilizer without incorporation at double rate 40 kg/ha and 7) P fertilizer applied as broadcast fertilizer without incorporation at quadruple rate 80 kg/ha. There will be four replicates of each treatment for a total of 28 plots. The same experiment will be set up at two locations: upslope and low slope positions of the landscape to provide a contrast in surface curvature, soil properties (pH, organic matter content, carbonate content) effects on fate of the added phosphorus. Therefore, the experimental site will contain a total of 52 plots. The cropping sequence used will be a pulse cereal-oilseed (short-season soybean-wheat-canola) rotation.
Measurements that will be made in 2014-2015 are initial soil nutrient status of the two locations, soybean straw and grain yield, phosphorus concentration, uptake and recovery in each of the plots. In the fall of 2014 after harvest, each plot will be sampled to assess soil extractable available phosphorus, resin exchangeable phosphate, water soluble phosphate and other nutrients in the soil profile. Intact slabs (0-15cm) of surface soil will then be removed from selected treatment plots and frozen. In the phytotron facility at the University of Saskatchewan, the frozen slabs will be placed in insulated boxes and snow placed on the surface followed by a simulated spring thaw. Surface and sub-surface water from the simulated snowmelt will be collected and analyzed for total P, particulate P and soluble (<0.45 micron) reactive orthophosphate concentration. An assessment of P speciation in the water using spectroscopy will be made.