Agronomic Application of Cattle Manue and Compost on Irrigated Cereal in Southern Alberta: A Field Study

 
 
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 Introduction | Study Methods | Findings | Conclusions | Acknowledgements | Publication | For More Information

Introduction

Land application is the most effective means of utilizing livestock manure. However, over-application of manure, relative to crop nutrient requirements, can lead to environmental problems. Of particular concern is the accumulation of excess nitrogen (N) and phosphorus (P) in soil and the potential degradation of surface and ground water quality. Several studies have examined the effects of over-application of manure in Alberta, but there is limited research on the agronomic use of manure in southern Alberta. The application of manure based on crop nutrient requirements is considered a beneficial management practice.

The purpose of this field study was to assess the effects of crop-based nitrogen (N) and phosphorus (P) application rates of cattle manure and compost on crop productivity and extractable soil N and P.

Study Methods

The 6-yr (2002–2007) field study was carried out about 2 km east of Lethbridge, Alberta on a clay-loam textured Orthic Dark Brown Chernozemic soil.

The experimental design included 10 treatments: control (CONT; no added nutrients), fertilizer N (F-N), fertilizer P (F-P), fertilizer N plus P (F-NP), N-based manure (M-N), P-based manure (M-P), three-times the P-based manure applied once every three years (M-3P), N-based compost (C-N), P-based compost (C-P), and three-times the P-based compost applied once every three years (C-3P). If necessary, supplementary N fertilizer was also added to the P-based manure and compost treatments. The source of manure and compost was from feedlot cattle. The treatments were replicated five times and arranged in a randomized complete block design. Individual plots were 6 by 8 m in size.

Soil samples were collected annually to a depth of 1.5 m in the fall from 2001 to 2007. The samples were air dried and ground (2-mm sieve) and analyzed for extractable nitrate N and extractable soil-test P (STP) contents.

Commercial N fertilizer was applied each spring (2002 to 2007) prior to seeding as banded urea fertilizer (46-0-0). Commercial P fertilizer was applied with the seed using 0-45-0 fertilizer. Manure and compost were applied by hand and incorporated immediately after application using disks. All nutrient sources were applied based on soil testing, fertilizer recommendations, and assumed nutrient availability in manure and compost. For example, it was assumed that 25% of organic N and 70% of total P in manure and 13% of organic N and 60% of total P in compost were mineralized during the first crop year after application. Residual nutrient carryover from manure and compost was taken into account in subsequent years.

The test crops were triticale in 2002, 2003, 2005, and 2006, and barley in 2004 and 2007. The site was irrigated using a solid-set sprinkler system. The plots were harvested at the silage stage.

Findings
Soil Extractable Nitrate Nitrogen

The average nitrate-N concentration among the plots ranged from 13.2 to 20.5 mg/kg in the 0- to 0.6-m soil layer and from 4.8 to 9.9 mg/kg in the 0.6- to 1.5-m soil layer prior to the start of the study in fall 2001. There were no treatment differences after the first crop year in 2002, but there were significant differences in each year after 2002. After six crop years, the nitrate-N content of the two treatments that did not receive N inputs (i.e., CONT and F-P) had the lowest amount of nitrate N in the soil profile in 2007. Nitrate N content decreased slightly after the first year and then remained relatively stable for the other treatments that received N. There was no net accumulation of nitrate N or continued depletion in the treatments that received N inputs. This suggests that the correct amount of N was applied to meet agronomic needs of the crop without over-application from the manure or compost.

Soil-test Phosphorus

Soil-test P concentration ranged from 9.2 to 14.9 mg/kg in the 0- to 0.15-m soil layer in fall 2001. Treatment effects on STP concentration were generally restricted to the 0- to 0.15-m soil layer. The N-based manure and compost treatments caused an increase in STP concentration with time. After six years, the STP concentration in the M-N treatment was eight-fold greater than the F-NP treatment, and the C-N treatment was ten-fold greater than the F-NP treatment. The two treatments without added P (i.e., CONT and F-N) had the lowest STP concentration and were less than the STP content at the start of the study. The P-based application treatments remained relatively constant with no accumulation or depletions in STP. Soil-test P concentration was also significantly higher in the 0.15- to 0.6-m soil layer. This suggests that a small amount of P did move into this layer. The STP concentrations tended to be the highest in the M-N and C-N treatments in the 0.6- to 1.5-m soil layer; however, the concentrations were not significantly different from the other treatments in the lower soil profile.

Even though most of the excess P applied in the N-based manure and compost treatments remained in the top soil layer (0 to 0.15 m), a small proportion of P did move into deeper soil layers. The accumulated STP caused by the N-based manure and compost treatments may increase the risk of P loss to surface runoff. It should be noted that when manure was applied based on N, the STP concentration increased to above the agronomic threshold of 60 mg/kg within only two years. The agronomic threshold is generally the level of STP beyond which most crops will no longer respond to added P.

Crop Yield

The CONT treatment consistently produced the lowest yield each year. The total six-year yield for the CONT was significantly less than the other treatments. The F-N and F-P treatments produced the next highest total yield and were significantly less than the F-NP treatment and most of the manure and compost treatments. The yields from the manure and compost treatments were not significantly different from the F-NP treatment. The manure and compost treatments generally provided similar yield, except that C-P yielded significantly less than the M-N and C-N treatments.


Conclusions

There was no net accumulation of nitrate N by any of the treatments. In contrast, the M-N and C-N treatments caused a rapid build-up of STP in the surface soil layer. Manure management, based on agronomic principles, can achieve optimum crop yield, but not necessarily prevent P build-up, when management is based on the N requirements of crops. Applying basic nutrient management principles (i.e., soil testing, crop nutrient recommendations, etc.) and using a combination of manure and commercial fertilizer can prevent N and P accumulation in soil and achieve optimum yield under irrigated conditions. Nitrogen-based management of manure and compost will cause P to accumulate in soil and this may increase the potential risk to surface-water quality.

Acknowledgements

Resources for this study were provided by Alberta Agriculture and Forestry. The manure and compost were provided by Agriculture and Agri-Food Canada.

Publication

Olson, B.M., McKenzie, R.H., Larney, F.J., and Bremer, E. 2010. Nitrogen- and phosphorus-based applications of cattle manure and compost for irrigated cereal silage. Canadian Journal of Soil Science 90: 619–635.

For More Information

Barry Olson
Alberta Agriculture and Forestry
Lethbridge, Alberta
Toll free 310-0000
Phone: 403-381-5884
Email: barry.olson@gov.ab.ca
 
 
 
 
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This information published to the web on August 4, 2015.