For the last decade, Argentinian CAFO’s have been increasing in number and size. Poultry farming showed remarkable growth and brought to light the absence of litter and nutrient management plans. Land application of poultry litter is the most common practice, but there is insufficient data to support recommended agronomic rates of application.
In this study, we developed the first comprehensive physiochemical characterization of poultry litter to accurately state average nutrient concentrations and data variability to support development of future litter best management practices. Simultaneously, we estimated the crop fertilization potential of poultry litter in Entre Rios Province.
Entre Rios Province contributes 51% of total Argentinian broiler production, holding over 2,600 chicken farms. Thus, the Ministry of Agriculture Industry contacted integrated broiler farmers, which all seemed to share a modern production protocol related to housing conditions, feed ration, and bedding management, and who were willing to participate in the sampling project. A sampling protocol was written following recognized literature sources (Zhang and Hamilton) and hands-on training sessions were developed with producers in charge of poultry litter sampling. A total of 55 broiler farms were sampled with 3 replicates per farm.
The following parameters were selected for analysis: organic matter, total nitrogen, ammoniacal nitrogen, organic nitrogen, phosphorus, potassium, calcium, magnesium, sodium, zinc, copper, electrical conductivity, pH and moisture content. Analytical procedures were stated with a certified local lab following recommended methods for manure analysis. A survey was also conducted at each sampling farm to assess variability on bedding age and material.
The average stocking density was 11.3 chickens/m2. The number of flocks grown on the litter before house cleaning ranged from 1 to 11 with an average of 4.7. However, 47.3% of the farms' litter had less than 5 flocks while 52.7% presented 5 or more flocks. There was no significant correlation between the physiochemical parameters measured and bird density, nor with the number of flocks raised on the litter.
Table 1. Litter Type
|Litter Type||Farms (%)|
|Woodchips + rice hulls||21.82|
While total nitrogen (TN) and phosphorus means were comparable to normal values reported in U.S. literature (Britton and Bullard; Zhang et al.), the variability of data was significant. Table 2 shows a summary of the most relevant analytical results obtained.
Table 2. Physical and Chemical Average Litter Composition (Dry Basis). SEM*: Standard Error of the Mean
|Mean||SEM*||St. Deviation||C.V. (%)|
|Organic matter (%)||79.13||0.62||4.61||5.82|
|Total nitrogen (%)||2.96||0.05||0.38||12.86|
|Electrical conductivity (mmhos/cm)||8.63||0.49||3.66||42.48|
|Moisture content (%)||31.50||0.63||4.65||14.78|
The coefficients of variation were especially high for phosphorus, sodium and electrical conductivity. This could be a critical factor governing poultry litter land application rates that promote neither phosphorus loss via surface runoff nor buildup of salts or sodium in the soil profile.
Raising over 359 million chickens annually, broiler litter value in Entre Rios Province would surpass 51 million dollars if it were fully used as commercial fertilizer substitute. Based upon the average nutrient content, 51,100 tons of nitrogen, 17,100 tons of phosphorus and 23,600 tons of potassium would be available; enough to fertilize 349,000 hectares of corn based upon crop nitrogen requirements whilst a plan based upon phosphorus would supply 629,000 hectares. Other critical factors like storage duration of litter outdoors, land application method, and the availability of litter nitrogen will impact the final calculation of plant available nitrogen (PAN), which is generally assumed to be 50% of TN when surface applied (Chastain et al.). Entre Rios farmers sow around 245,000 hectares of corn annually, hence 71% of the planted area could potentially be fully nitrogen fertilized using broiler litter instead of commercial fertilizer.
These results showed that while there is strong potential for litter land application at agronomic rates in Entre Rios, individual litter samples properly taken and analyzed are still needed to sustain environmentally sound nutrient management plans due to the large variability of the analytical results.
The information presented will be utilized as input data for developing draft Broiler Farms’ Nutrient Management Plans that will serve as a model for other Argentinian CAFO. Currently, laboratory results from Buenos Aires Province hen farms are being analyzed.
Roberto Maisonnave, President at AmbientAgro - International Environmental Consulting
Karina Lamelas, Director of Poultry and Swine Production at Ministry of Agriculture (Argentina). Gisela Mair, Ministry of Agriculture (Argentina). Norberto Rodriguez, Ministry of Agricultrue and University of Tres de Febrero (Argentina).
Britton, J. and G. Bullard. 1998 Summary of Poultry Litter Samples in Oklahoma. Oklahoma Cooperative Extension Service. CR-8214.
J. Chastain, J. Camberato and P. Skewes. Poultry manure production and nutrient content. Poultry Training Manual. Clemson University. http://www.clemson.edu/extension/camm/manuals/poultry_toc.html
Maisonnave, R.; Lamelas, K. y G. Mair. Buenas prácticas de manejo y utilización de cama de pollo y guano. Ministerio de Agroindustria de la Nación Argentina. 2016.
Zhang, H. and D. Hamilton. Sampling animal manure. Oklahoma Cooperative Extension Service. PSS-2248.
Zhang, H.; Hamilton, D. and J. Payne. Using Poultry Litter as Fertilizer. Oklahoma Cooperative Extension Service. PSS-2246.
Dr. Jorge Dillon and Ing. José Noriega (SENASA)
Ing. Agr. Juan Martin Gange and Lic. Corina Bernigaud (INTA)
Ing. Agr. Alan Nielsen and M. Vet. Juan Nehuén Rossi (Granja Tres Arroyos)
Lic. Pablo Marsó (Las Camelias)
Sra. Nancy Dotto (Soychú)