Location: Northwest Irrigation and Soils Research
Project Number: 2054-12000-012-001-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Mar 1, 2020
End Date: Feb 28, 2025
Objective:
Develop recommendations for optimal manure application rates and timing (annual or biennial; few years or several years of manure application), on the basis of yield potential, crop quality, soil quality, disease pressure, and nutrient uptake. To monitor the long term effects of historical manure application on soil nutrient status and cycling.
Approach:
The study is currently being conducted on two adjacent 2.5 acre sprinkler irrigated fields at the USDA ARS NWISRL station in Kimberly, Idaho. The soil type is Portneuf silt loam, which is the most commonly farmed soil type in Southern Idaho.
The current crop rotation was wheat-potatoes-barley-sugar beets from 2013-2019. Both fields will be planted to sugarbeet in 2020. The crop rotation starting in 2021 will likely consist of corn-winter canola-sorghum sudangrass-winter wheat or rye. Treatments continuing on one field will include timing (manure application every year or every other year (before grain)) and rate (8, 16, and 24 ton/acre, dry weight basis). Additional fertilizer treatment (chemical fertilizer applied at agronomic rates based on UI fertilizer guides) and a control treatment (no nutrient source applied) will also be included, for a total of 8 treatments (2 timings x 3 rates + 1 fertilizer trt + 1 control trt). Treatments will be replicated 4 times in a randomized complete block design, for a total of 32 treatments per field. The second field will have no manure/fertilizer applications.
The manure source will be a partially dried dairy manure that has been stockpiled at least one year, representing a dairy manure source that is commonly applied to fields in Southern Idaho. Triplicate manure samples will be analyzed by a Minnesota Department of Agriculture certified manure testing lab for moisture, soluble salts (EC), pH, organic matter, carbon (C), and most agronomic nutrients. Manure is applied in the fall to specified treatment plots by pre-weighing the amount of manure equivalent to the treatment rate, and applying the manure using a small-plot manure spreader from the USDA ARS Kimberly station. Manure is incorporated on the same day as application to avoid ammonia volatilization losses.
Response variables will continue to include soil tests and plant analysis. Soil tests will include 1) spring comprehensive soil test prior to fertilization and planting for individual plots at 0-12 and 12-24 inch depths, 2) pre-sidedress nitrate test in mid-June, individual plots at the 0-12 inch depth and 3) post-harvest deep core sampling down to a 72 inch depth (divided into 1 foot increments). Soil analysis will be conducted at the USDA-ARS research laboratory and UI Analytical Sciences Lab in Moscow, Idaho.
