Background The control of N losses during one phase of the manure management chain (animal housing, manure storage and manure application) could enhance them in subsequent phases. Therefore, it is crucial to develop and evaluate effective measures that will reduce the losses throughout the whole chain and enhance crop N utilization after manure field application.

ObjectivesTo quantify the mitigating effects of three bedding additives, i.e. zeolite, lava meal and sandy farm topsoil (Fig. 1), on NH3 emissions during storage and after land application of cattle straw manures.To determine herbage apparent N recovery (ANR) after surface spreading of the manures on grassland.

(a) (b) (c)Fig. 1. Bedding additives: (a) zeolite (b) lava meal and (c) sandy farm topsoil

(a) (b)Fig. 2. Measurement of NH3 concentrations (a) during storage and (b) after land spreading of cattle straw manure

Material and methodsBedding additives were applied inside a naturally ventilated sloping-floor barn at rates proportionally to the daily straw dosage of 5 kg per livestock unit, i.e. 10% of zeolite, 20% of lava meal and 33% of sandy farm topsoil.

The trampled-down straw manures by the bulls were collected twice daily from the barn and stockpiled inside a roofed building as four separate heaps.

After storage, all the manures were surface-spread manually on cut grassland at an application rate of 400 kg N ha-1.

Herbage ANR was calculated with the N difference method.

NH3 emissions from the surface of each manure heap were determined by using a photoacoustic gas monitor (Fig. 2a).

NH3 concentration in the air above each plot was measured immediately after manure spreading by means of diffusion samplers (Fig. 2b) for 72 hours and corrected for the background concentration.

Bedding additives reduce ammonia emissions during storage and after application of cattle straw manure, and improve N utilization by grassland

G.A. Shah*, J.C.J. Groot, P.W.G. Groot Koerkamp and E.A. Lantinga

Results and discussionAll the additives reduced NH3 emissions by about 87% during storage and on average 69% after surface application to grassland (Table 1). This could be attributed to adsorption of ammonium (NH4

+) by all of the additives and possible formation of struvite salt by the lava meal.

The herbage apparent N recovery was increased from 11% (control) to about 26% by all of the additives (Table 2). This could be attributed to:I. The reduced losses of NH3 and other gaseous N compounds.II. Prevention of nitrification and subsequent nitrate leaching through NH4

+ adsorption.

‡‡ Untreated manure.† Means in the same column with different letters differ significantly (P < 0.05).‡Values in parentheses in the same column represent relative losses compare to the control.

‡ Untreated manure.† Means in the same column with different letters differ significantly (P < 0.05).

Conclusion

Use of the bedding additives not only reduced NH3 emissions impressively during storage and after field application, but also increased herbage ANR from the manures more than twofold.

*Organic Farming Systems Group, Department of Plant Sciences, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.

Phone: + 31 (0)317481192, E-mail*: ghulam.shah@wur.nl

Treatment Total of 3 cuts

DM yield N uptake ANR

(Mg ha-1) (kg ha-1) (%)

Zero 2.2 a† 43.1 a

Control‡ 3.6 b 87.6 b 11 a

Zeolite 5.1 c 148.2 c 26 b

Farm topsoil

4.9 c 141.7 c 25 b

Lava Meal 5.3 c 153.8 c 28 b

Treatment  

During storage After application

Total NH3-N emission

NH3 concentration

(g Mg-1 of fresh manure)

(µg m-3)

Control‡‡ 25.3a† (100)‡ 117.5a (100)Zeolite 3.2b (13) 30.1b (26)Farm topsoil

3.6b (14)29.4b (25)

Lava meal 2.7b (11) 50.9b (43)

TABLE 1: Total NH3 emission during 80 days of storage and average NH3 concentration during 3 days after application on grassland

TABLE 2: Total herbage dry matter (DM) yield, N uptake and apparent N recovery (ANR) over 3 cuts