Effects of Method of Applying Liquid Manure on Ammonia Emission (2001)

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Experiment & Measurement of Ammonia Loss

Scientists at the Pacific Agri-food Research Centre of Agriculture and Agri-Food Canada, in collaboration with Holland Hitch Ltd., have developed a new precision, high-speed implement for applying liquid manure into the soil of grassland, minimum-tilled crop land as well as conventionally tilled fields.

The new applicator, called Aerway SSD, applies slurry in narrow bands directly over surface openings made by its ground-driven aerator tines, in one operation. Compared to broadcasting with a conventional splash-plate applicator, the Aerway SSD applies manure more uniformly and with less exposure to the air. Compared to conventional injectors, SSD causes less soil disturbance, requires less power, can be used on stony land, and is available in wider units. Scientific evaluation of this new technology was started in 1999 in order to assess agronomic crop response, nutrient use efficiency, and ammonia loss relative to conventional manure application. This report summarizes first-year results of a study to compare ammonia loss from dairy slurry applied on grassland with the Aerway SSD, surface banding with drop-hoses and conventional broadcasting with a splash-plate.

EXPERIMENTS

Two trials (July 21 and August 17) were conducted on a 5-year-old stand of tall fescue and one trial (Sept. 1) was on a 2-year-old stand of orchardgrass. Manure application rates ranged from 70 to 115 kg ammonia-N/ ha and from 55,000 to 75,000 litres/ha. The splash-plate spread a 9-m wide strip; the SSD unit (also used for the drop-hose treatment) was 4.5 m wide. The bands of both the drop-hose and the SSD treatments were spaced 19 cm apart. The soil openings made by the Aerway SSD, set at 2.5 degree offset, measured 15- to 18-cm deep, 20-cm long and were spaced 20-cm apart in the row.

MEASUREMENT OF AMMONIA LOSS

There are different methods for measuring volatilization losses of ammonia following land application of manure. The micro-meteorological method uses small samplers mounted at different heights on towers located around the perimeter of a treated area. This method does not affect the airflow over the soil but large plots (at least 20 by 20m) are required. In contrast, the semi-open chamber technique, used in this study, does not require large plots so a larger number of treatments can be monitored at once. However, these chambers restrict airflow, reducing ammonia loss, and hence capture smaller amounts of ammonia than the methods that use either ventilated chambers or no chambers at all. Nevertheless, previous work has shown that the semi-open chamber can reveal relative differences among application technologies. Results from the micro-meteorological study will be summarized in a future report.

The ammonia in these chambers was trapped in sorption pads soaked in acid. Ammonia extracted from the sorption pads was quantified with a flow injection autoanalyser. Three chambers were used for each experimental plot. Ammonia samples were collected 1, 2, lete and 13 days after manure was applied.

Photos below show manure application with the SSD and splash-plate applicators at approx. 7,000 gal/acre (70,000l/ha).

Results

Trial 1 (See Table 1)

In Trial 1, ammonia losses for Day 1, Day 2 and total losses over the 13-day measurement period had the ranking: splash-plate > drop-hose > Aerway SSD. Total ammonia loss from manure applied with the Aerway SSD was 33% lower (significant at P

Table 1. Ammonia loss after application of dairy manure-slurry with different implements in Trial 1 started on July 21, 1999

.

Treatment

----Ammonia Loss(kg/ha)----

. Splash-plate Hose Aerway SE*
Day 1 3.95a** 3.19a 1.93b 0.33
Day 2 1.16a 1.07a 0.74a 0.04
Day 3-5 1.18a 1.31a 1.03a 0.18
Day 6-13 1.07a 1.29a 1.15a 0.04

** Treatment means in each row that are followed by the same letter are not statistically different at P*Y Standard error

Trial 2 (See Table 2)

In Trial 2, ammonia losses in Day 1 and total losses over the 14-day measurement period had the same ranking as in Trial 1: splash-plate > hose > Aerway SSD. After Day 1, emissions were low with no significant differences among treatments. Total ammonia loss over the measurement period was significantly (P

Table 2. Ammonia loss after application of dairy manure-slurry with different implements in Trail 2 started on Aug. 17, 1999

.

Treatment

----Ammonia Loss(kg/ha)----

. Splash-plate Hose Aerway SE*
Day 1 7.52a 3.30b 3.15b 0.60
Day 2 1.09a 0.90a 0.87a 0.10
Day 3 0.40a 0.27a 0.30a 0.06
Day 4-16 0.41a 0.48a 0.44a 0.09
Day 7-14 0.16a 0.12a 0.15a 0.02
Total (Day 1-14) 9.58a 5.07a 4.91a 0.77
** Treatment means in each row that are followed by the same letter are not statistically different at P* Y Standard error

Trial 3 (See Table 3)

Ammonia loss for all periods, and the total over all periods, was greater for the splash-plate than the Aerway SSD. Highest ammonia emissions were measured during this trial, probably due to the warm conditions that are conducive to volatilization of ammonia. Ammonia losses were significantly lower for the Aerway SSD than the splash-plate in all Periods (except Day 3-5), and for the entire period by 62%. Ammonia losses during the first day were 64% and 71% of the total measured over 13 day for the splash-plate and Aerway SSD applicators, respectively. Ammonia emission from the non-manured plots (control) over 13-day measurement period averaged 0.14 kg/ha.

Table 3. Ammonia loss after application of dairy manure-slurry with different implements in Trial 3 on Sept. 1, 1999

.

Treatment

----Ammonia Loss(kg/ha)----

. Splash-plate Aerway SE*
Day 1 8.59a** 3.67b 0.42
Day 2 1.58a 0.48b 0.03
Day 3-5 1.54a 0.40a 0.28
Day 5-13 1.50a 0.42b 0.14
Total (Day 1-13) 13.21a 4.97b 0.86

** Treatment means in each row that are followed by the same letter are not statistically different at P* Y Standard error

Observations & Acknowledgements

Some Observations

Results from the three trials showed significantly lower ammonia emission losses (33%, 47%, and 62%) for the Aerway SSD manure applicator compared with the splash-plate. Average reduction in ammonia emission loss by the Aerway SSD, over the three trials, was 47%.

Results for banding manure with the drop hoses were less consistent, but on average, intermediate between the splash-plate and the SSD.

  • Over half of the total amount of ammonia loss occurred during the first day in all trials; this proportion was greater for the splash-plate than the SSD.
  • Differences among methods were less apparent after Day2.
  • Results presented in this report are preliminary. Additional results using the micro-meteorological technique and from trials conducted in the year 2000 will be summarized in a future report.

ACKNOWLEDGEMENTS

We are grateful to the following people for their contribution to this project: F. Bounaix, A. Friesen, S. Briant, M. Schaber, X. Wu, C. Vanlaerhoven. We gratefully acknowledge the financial support by BC Investment Agriculture, Agriculture Canada Matching Investment Initiative and Holland Hitch Ltd.

L.J.P. van Vliet, S. Bittman, and E.A. Kenney

Pacific Agri-Food Research Centre, Box 1000, Agassiz, B.C. Canada V0M 1AO

Contact: Laurens van Vliet (604-796-2221 ext.223) or E-mail VanVlietL@em.agr.ca

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