Manure Management Effects on Surface and Groundwater

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Since 1992, manure application on cropland has been made on a farm of a swine farrow-to-finish production unit of 200 sow. Monitoring of the surface and groundwater has been made and the results show that most of the nutrient losses occurred as tile flow. Concentration of nutrients have been measured and the average of nitrate-N levels were slightly above the health recommended concentration, 13,8 mg/L compared to 10mg/L. Leaching from commercially fertilized crop ground are generally slightly higher than the value found. The phosphorus concentration averaged 0,6 mg/L. The nutrient losses from runoff was not significant as very little occurred. Testing on groundwater was also done. The results show that higher nitrate concentrations could be measured the years after fall application had been done and when the overapplying manure. The average concentration in ground water for the 3 rates and the two years samples is 13,6 mg/L.

The application rates of nutrients from manure were: for 1992, 157 kg/ha of N and 48 kg/ha P; for 1993, 215 kg/ha of N and 137 kg/ha of P and finally for 1994, 198 kg/ha and 122kg/ha de P. The manure treatments on the plots consisted of no manure, the application rates presented, 2 times the application rates and the final one was 3 times the application rates.

A possible relationship between low facility dust and endotoxin levels and improved growth rates in pigs reared by Isowean(SM).

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Dust concentrations and total and respirable endotoxin were measured in 2 types of pig-rearing facilities: an isolated nursery and nursery within a conventional farm. Dust and endotoxin concentrations were significantly higher in the conventional nursery compared with the isolated nursery. Pigs in the isolated nursery had significantly higher body weights and larger thymus glands, spleens and cervical lymph nodes than animals reared in the conventional farm. It is suggested that there may be an association between environmental facility contaminants and growth rate.

Water use and drinker management: a review.

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The importance of water intake for pigs is presented and the wastage done, the water intake of pigs, the drinking behavior and the types of drinkers are discussed. In order to reduce to a minimum the wastage, the management of nipple drinkers is necessary and the height of the nipple has to be varied with the animal body weight and can be determined for nipples mounted at a 90 degree angle using the following relationship: 15 * BW^0,33 cm (where BW is the body weight in kg). For downward mounted nipple the height is determined in cm using 18 * BW^0,33 which represents approximately 120% of the pig’s shoulder height. The height should be determined in order to accommodate the smallest pig in the pen. Flow rate should also be controlled in order to minimize the wastage. For nipple drinker, here are recommended values: for the nursery, 500 ml/min; for grow/finish, 700 ml/min; for gestation, 1000 ml/min and for lactation 1500 ml/min.

Means to reduce water wastage have to be considered as the excess manure produced has to be stored and subsequently spread. The extra water coming from spillage contribute only in more dilution of the nutrients in the manure. Useful management tips for nipple drinkers are presented here.

Availability of Residual Phosphorus in Manured Soils

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As manure is often applied to meet the nitrogen requirement of the crop, phosphorus is thus applied in excess and will stock in the soil. When agronomically and environmentally management systems are integrated by farmers, it become difficult to evaluate how P will decrease in the soil. The method discussed was used to evaluate the release of P for different soil types, management and fertility status. Such release would be done to the plants over the years and crops however using Fe-oxide strips (iron oxide) allowed to verify the P availability more rapidly. This method could be used to compared and find optimal crop management for different types of soil.

Investigation have to be done to find ways to lower the phosphorus level in soil where manure still have to be spread on land. Different crop systems on specific soils could be optimum in using the available P however, this evaluation process takes time if we consider only annual cropping experiments. The method developed seems to be an interesting approach to speed this evaluation.

Chronic exposure of pigs to airborne dust and endotoxins in an environmental chamber: technical note.

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A new experimental setup was developed to expose pigs to dust and airborne endotoxins in an environmental chamber. 2 pigs of 10 kg body-weight were housed in a chamber to measure inhalable and respirable dust gravimetric concentrations using area samplers. The respirable dust concentration was also measured using a TM digital microP respirable dust-measuring instrument. The endotoxin concentration was evaluated using the Limulus-assay and expressed as ng/m3 of air containing the inhalable or respirable dust or as ng/mg of inhalable and respirable dust. Feed flour dust was introduced into the chamber to obtain different concentrations of inhalable and respirable dust ranging from 3.62 to 76.66 mg/m3 and from 0.24 to 1.40 mg/m3, respectively. The endotoxin concentration was modulated by mixing the feed flour with Escherichia coli endotoxins before blowing it into the chamber. The endotoxin concentrations in the air containing inhalable or respirable dust ranged from 28.9 to 270.0 ng/m3 and from 2.22 to 36.38 ng/m3, respectively, depending on the amount of endotoxins added to the dust. It is concluded that this experimental setup could be used to study the significance of air contaminants in the development of pig respiratory diseases.

Ice Pressures in Liquid Manure Tanks

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The ice in manure concrete manure tanks present an additionnal load on the structure and ice thickness has to be determined for a given geographical situation in order to consider it in the design of the structure. Improperly design manure storage structures can fail and cause leakage and environmental contamination.

Availability of Macronutrients to Field Crops from Alternative Manure Systems

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This chapter review the situation on the availability of macronutrients, nitrogen (N), phosphorus (P) and potassium (K) by field crops. The importance of ammoniacal N is presented, this N portion is rapidly used by the crop and its availability is close to fertilizer N. Method and time of manure application are also discussed. To improve N utilization by the crop, the contact of manure to air while spreading should be lowered to a minimum and spreading time should be as close as possible to the time the plant is going to need N. Long term ammonia release after spreading is discussed along with methods to measure the N availability in manure. P availability to crops is also discussed and is considered to be as available as fertilizer P, a value of about 40%. Part of the phosphorus in the manure is organic P and represent 5 to 15% of the total P in the manure. More research is needed to evaluate if the availability of 40% is really valid. Long-term manure P contributions to soil should still be evaluated by soil P tests. As for K, its availability is considered as high as for fertilizer K.

Recirculation of filtered air in pig barns.

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Recirculating air filtration systems were tested to reduce dust and bacteria levels inside the feeder barns of a hog farm in the Fraser Valley of British Columbia. Design of the air filtration systems had to be reconciled with the existing structures and ventilation system in the barns. Multiple fabric filters and a high-voltage, plate-type electrostatic precipitator were selected as dust collection devices for the grower and finisher barns, respectively. Each barn was partitioned into two halves with one serving as the experimental unit equipped with the air filtration system and the other as the control unit. Recirculation air flow rate was set at 20 air changes per hour which lies between the summer and winter ventilation rates. Monitored parameters included air quality indices (respirable and inhalable dust levels, bacterial counts, and ammonia level), environmental and operating parameters (temperature, relative humidity, filter pressure drop, and air flow rate), and animal performance (average growth rate, carcass grading, and necropsies). Visits to the farm were conducted regularly once a week during the first 9 months and subsequently once every two weeks during the rest of the 18-month period of the study. The air filtration systems effectively reduced dust levels and aerial bacteria counts inside the pig barns although their efficiency was dependent upon air recirculation flow rate, location, size, and number of inlets and outlets, and humidity. Although the effect on indoor ammonia level was indeterminate, air filtration resulted in reduced prevalence of enzootic pneumonia and atrophic rhinitis among the pigs. It also accelerated animal growth as evidenced by an increase in average daily mass gain which translated to a shorter number of days to market. Air filtration showed no significant effect on the temperature and humidity inside the barn. The electrostatic precipitator exhibited higher dust removal efficiency during winter and spring time and was almost as effective as the fabric filter during the other seasons of the year. In terms of bacteria reduction, the electrostatic precipitator was consistently more effective than the fabric filters.

Structural Design of Liquid Manure Tanks

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Improperly design manure storage structures can fail and cause leakage and environmental contamination. This publication review the parameters that have to be considered for concrete manure storage conception to assure maximum lifetime of the structure.

Transport of Nitrogen, Phosphorus and Disease Organisms from Manure into Surface and Groundwater.

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This chapter, the factors that can have an impact on water quality are reviewed particularly for contamination of ground and surface water by nitrate, phosphorus and disease organisms. The focus is made on potential contamination as a result of manure application on land. The first step is to present the unbalanced nutrients ratio N:P:K of the swine and dairy manure (2:1:1,5 and 4:1:3 respectively) compared to the need of heavy yielding corn (7:1:7) for example. This would suggest not to use N as the limiting factor but rather to use P and supplement for the other nutrients. However the availability of nutrients is difficult to assess particularly for N as many losses can occur depending on the climatic conditions and also on the spreading method as NH3 can be emitted directly as gas, nitrification can occur and nitrate can be lost by leaching and denitrification can also occur resulting in N2O and N2 as gaseous emissions. N deposition can also come from the atmosphere, quantity which is difficult to evaluate. The survival of different pathogenic bacteria depends on different factors for example: soil pH, soil water and organic matter contents, soil texture, temperature and others. It is thus difficult to predict the bacteria becoming as a general trend. The transport of the contaminant is dependent of their concentration in the soil and also on the water flow available to move them. The application rate of the manure and also the number of years of repeated manure applications have a direct effect on the nitrate potentially available for leaching. So the higher are the rates and the more years the manure is applied, the higher are the risks for leaching contaminants in water. Manure spreading the closer to the crop growing period lower also the risk for nitrate leaching. Injection rather than surface application lower the risk of leaching. Some paths are given for further research particularly on the availability of nitrogen and other nutrients in the manure, the transport of those nutrients that can become contaminants under certain circumstances and the more information on disease organisms and the factors affecting their transport.

Many elements are presented in this review. Some conclusions can be drawn from this information and they are that specific factors increase the risks for leaching of contaminants and degradation of water quality and they are: high application rate; application done a long time before the growing season; manure applied directly on soil rather than injected particularly during rainy periods.