Manure Application Methods Research Articles

Swine Manure Injection with Low‐Disturbance Applicator and Cover Crops Reduce Phosphorus Losses

Injection of liquid swine manure disturbs surface soil so that runoff from treated lands can transport sediment and nutrients to surface waters. We determined the effect of two manure application methods on P fate in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] production system, with and without a winter rye (Secale cereale L.)-oat (Avena sativa L.) cover crop. Treatments included: (i) no manure; (ii) knife injection; and (iii) low-disturbance injection, each with and without the cover crop. Simulated rainfall runoff was analyzed for dissolved reactive P (DRP) and total P (TP). Rainfall was applied 8 d after manure application (early November) and again in May after emergence of the corn crop. Manure application increased soil bioavailable P in the 20- to 30-cm layer following knife injection and in the 5- to 20-cm layer following low-disturbance injection. The low-disturbance system caused less damage to the cover crop, so that P uptake was more than threefold greater. Losses of DRP were greater in both fall and spring following low-disturbance injection; however, application method had no effect on TP loads in runoff in either season. The cover crop reduced fall TP losses from plots with manure applied by either method. In spring, DRP losses were significantly higher from plots with the recently killed cover crop, but TP losses were not affected. Low-disturbance injection of swine manure into a standing cover crop can minimize plant damage and P losses in surface runoff while providing optimum P availability to a subsequent agronomic crop.

Environmental and Economic Comparisons of Manure Application Methods in Farming Systems

Alternative methods for applying livestock manure to no-till soils involve environmental and economic trade-offs. A process-level farm simulation model (Integrated Farm System Model) was used to evaluate methods for applying liquid dairy (Bos taurus L.) and swine (Sus scrofa L.) manure, including no application, broadcast spreading with and without incorporation by tillage, band application with soil aeration, and shallow disk injection. The model predicted ammonia emissions, nitrate leaching, and phosphorus (P) runoff losses similar to those measured over 4 yr of field trials. Each application method was simulated over 25 yr of weather on three Pennsylvania farms. On a swine and cow-calf beef operation under grass production, shallow disk injection increased profit by $340 yr(-1) while reducing ammonia nitrogen and soluble P losses by 48 and 70%, respectively. On a corn (Zea mays L.)-and-grass-based grazing dairy farm, shallow disk injection reduced ammonia loss by 21% and soluble P loss by 76% with little impact on farm profit. Incorporation by tillage and band application with aeration provided less environmental benefit with a net decrease in farm profit. On a large corn-and-alfalfa (Medicago sativa L.)-based dairy farm where manure nutrients were available in excess of crop needs, incorporation methods were not economically beneficial, but they provided environmental benefits with relatively low annual net costs ($13 to $18 cow). In all farming systems, shallow disk injection provided the greatest environmental benefit at the least cost or greatest profit for the producer. With these results, producers are better informed when selecting manure application equipment.

Manure Application under Winter Conditions: Nutrient Runoff and Leaching Losses

Winter application of manure is commonly practiced in the northeastern and north-central U.S. Potential nutrient losses from winter-applied manure are difficult to predict due to uncertainty in weather forecasting and limited knowledge on soil-nutrient-hydrology interactions during the winter. The objective of this study was to extend the understanding of nutrient cycling and transport processes associated with manure application methods during winter months. Specifically, the influence of manure position within the snowpack on nutrient losses was examined using a laboratory approach. Dairy manure was applied either before, midway through, or upon completion of an artificial snowfall. Runoff and leachate were subsequently collected throughout a snowmelt event and rainfall simulations. Manure application prior to the snowfall increased the losses of total N and NH4-N in snowmelt runoff and resulted in larger losses of both N and P in runoff during the rainfall simulation. Manure application on top of the snow reduced the amount of NH4-N losses but increased the losses of organic N, DRP, and total P in snowmelt runoff. The results of this research show that the relative position of manure within the snowpack plays a significant role in the fate of N and P from winter-applied manure.

Response of grain amaranth (Amaranthus cruentus L.), to method and rate of cattle kraal manure application at Kadawa and Samaru in Nigeria

Field experiments were conducted between June and October 2010 wet season at two different locations. The first was at the Horticultural Research Garden of the Institute for Agricultural Research (IAR), Samaru in the Northern Guinea Savanna agro-ecological zone and the second experiment was conducted at the Research Farm of the Irrigation Research Sub-Station (IRS), Kadawa in the Sudan Savanna agro-ecological zone also of the Institute for Agricultural Research, Ahmadu Bello University, Zaria, Nigeria to evaluate the response of grain amaranth growth and green edible vegetable yield components to three methods of cattle kraal manure application (broadcasting, side banding and spot placement incorporated) and five rates of cattle kraal manure application (0, 5, 10, 15 and 20 t ha-1), using the variety ?Pure branch?. The experiment was laid out in a randomized complete block design (RCBD) and replicated three times. Cattle kraal manure application rates significantly (p > 0.05) increased growth of green edible vegetable yield characters of grain amaranth except stem girth at Samaru. Growth and green edible vegetable yield characters were generally not influenced by methods of cattle kraal manure application except for plant height, number of leaves per plant at 12 WAT at Samaru, and plant fresh weight at 12 WAT at Kadawa and dry weight at 4 and 12 WAT at Samaru and 12 WAT at Kadawa. Application of cattle kraal manure of 10 t ha-1 to Amaranthus cruenthus gave the highest mean values which were comparable to those of 15 and 20 t ha-1 rates for all the characters measured such as plant height, number of leaves, leaf area, fresh and dry weights. Thus, the finding suggests that 10 t ha-1 should be recommended to farmers growing Amaranthus in the Northern Guinea and Sudan Savanna of Nigerian agro-ecologies.

Leaching of Salmonella enterica in Clay Columns Comparing Two Manure Application Methods

Transfer of zoonotic bacterial pathogens through intact soil columns was monitored in an outdoor lysimeter over 36 d. Manure spiked with Salmonella enterica serovar Senftenberg was applied to either the soil surface or injected 0.08 m into the soil to compare leaching associated with the two manure application methods. The highest concentrations of S. enterica (up to 60,000 S. enterica CFU/mL) were detected on Day 1 in the first drainage samples, with measurable but declining concentrations persisting for 10 to 36 d depending on replicate columns. The total recovery of leached S. enterica in drainage samples ranged from 0.08% to 13.8%. When comparing the two application methods, there was no statistically significant difference in the leaching concentration of S. enterica at each sampling time during the study period. In addition, comparison of enumerations by selective plating and real-time polymerase chain reaction yielded similar concentrations of S. enterica, indicating that mainly viable and culturable cells were leached from the columns. When the experiment was terminated, the fluorescent dye Acid Yellow was applied to four selected columns and the distribution of dye and size of active (dye-stained) pores were measured with a digital camera and visualization software. The profiles showed that the area covered by active pores ranged from 0.1% to 3.6%. The relatively small fraction of active pores in the soil profile was consistent with the evidence of rapid transport of S. enterica and chloride in the columns.

Greenhouse Gas Emissions Measured 24 Hours after Surface and Subsurface Application of Different Manure Types

Greenhouse gas (GHG) emissions from agricultural activities such as land application of livestock manure cannot be ignored when assessing overall emissions from anthropogenic sources. The magnitude of these emissions is influenced by management practices such as manure placement during land application. The objective of this work was to compare GHG fluxes resulting from the surface and subsurface application of liquid and solid manure. For this comparison, all measurements were made 24 h after application using a static chamber method. The results showed that subsurface application significantly increased carbon dioxide equivalent (CO2-e) fluxes for both solid and liquid manure. The overall CO2-e fluxes from injected treatments were 3.2 times greater than CO2-e fluxes from the surface-applied plots, mainly due to a pronounced increase in N2O fluxes, which was likely caused by increased denitrification rates. The CO2-e fluxes from liquid manure applications were also greater than the CO2-e fluxes from solid manure applications, probably due to greater levels of ammonium available for nitrification and subsequent denitrification. Methane (CH4) fluxes were negligible for all manure types and application methods 24 h after application. For this particular study, measured specific fluxes (total flux per kg N applied) remained relatively constant with application rate, indicating that GHG emissions from manure applications were approximately proportional to the amount of manure applied.

Determination of ammonia and greenhouse gas emissions from land application of swine slurry: A comparison of three application methods

In this study, the comparison and monitoring of the initial greenhouse gas (GHG) emissions using a flux chamber and gas analyzer from three different liquid manure application methods at a swine farm in Kentucky were carried out. Swine slurry was applied to farmland by row injection, surface spray, and Aerway injection. Ammonia and GHG concentrations were monitored immediately after application, 72 and 216 h after application. The results showed that the initial ammonia flux ranged from 5.80 mg m −2 h −1 for the surface spray method to 1.80 mg m −2 h −1 for the row injection method. The initial fluxes of methane ranged from 8.75 mg m −2 h −1 for surface spray to 2.27 mg m −2 h −1 for Aerway injection, carbon dioxide ranged from 4357 mg m −2 h −1 for surface spray to 60 mg m −2 h −1 for row injection, and nitrous oxide ranged from 0.89 mg m −2 h −1 for surface spray to 0.22 mg m −2 h −1 for row injection. However, the Aerway injection method seemed to create the highest gas (GHG) concentrations inside the monitoring chambers at the initial application and produced the highest gas fluxes at subsequent sampling time (e.g., 72 h after application). Nevertheless, the surface spray method appeared to produce the highest gas fluxes, and the row injection method appeared to emit the least amount of greenhouse gases into the atmosphere. Gas fluxes decreased over time and did not depend on the initial headspace concentration in the monitoring flux chambers.

Case Study: On-Farm Evaluation of Liquid Dairy Manure Application Methods to Reduce Ammonia Losses

<h2>ABSTRACT</h2> The volatilization of NH₃ from land-applied manure is not only a loss of valuable N, but also an air quality concern because NH₃ plays a role in the formation of airborne particulate matter, which can be a health hazard. The relative differences in potential NH₃ losses from land application of liquid dairy manure were determined via 3 methods: surface application, Aerway incorporation (shallow incorporation with a rolling tine aerator), and subsurface injection. Liquid manure was applied at a rate of 190m³/ha on 4 farms with average N and P application rates ranging from 28 to 130kg N/ha and 6 to 36kg P/ha, respectively. Average NH₃ concentrations were measured with passive samplers for 3 d after manure application and ranged from 0.03 to 0.21mg NH₃-N/m³ There were main effects of sampler height, day, and application method. The greatest NH₃ concentrations occurred during the first 48h after manure application. Concentrations of NH₃ measured at 1m (averaged over 48 h) indicated that surface and Aerway applications had the greatest concentrations (0.16 and 0.17mg NH₃-N/m³, respectively) whereas subsurface injection of manure resulted in a 67% decrease in NH₃ concentration, which was similar to the control plots (0.06 and 0.04mg NH₃-N/m³, respectively). Subsurface injection was the best method of liquid manure application for minimizing NH₃ losses.

Assessing manure management strategies through small-plot research and wholefarm modeling

Plot-scale experimentation can provide valuable insight into the effects of manure management practices on phosphorus (P) runoff, but whole-farm evaluation is needed for complete assessment of potential trade offs. Artificially-applied rainfall experimentation on small field plots and event-based and long-term simulation modeling were used to compare P loss in runoff related to two dairy manure application methods (surface application with and without incorporation by tillage) on contrasting Pennsylvania soils previously under no-till management. Results of single-event rainfall experiments indicated that average dissolved reactive P losses in runoff from manured plots decreased by up to 90% with manure incorporation while total P losses did not change significantly. Longer-term whole farm simulation modeling indicated that average dissolved reactive P losses would decrease by 8% with manure incorporation while total P losses would increase by 77% due to greater erosion from fields previously under no-till. Differences in the two methods of inference point to the need for caution in extrapolating research findings. Single-event rainfall experiments conducted shortly after manure application simulate incidental transfers of dissolved P in manure to runoff, resulting in greater losses of dissolved reactive P. However, the transfer of dissolved P in applied manure diminishes with time. Over the annual time frame simulated by whole farm modeling, erosion processes become more important to runoff P losses. Results of this study highlight the need to consider the potential for increased erosion and total P losses caused by soil disturbance during incorporation. This study emphasizes the ability of modeling to estimate management practice effectiveness at the larger scales when experimental data is not available.

Assessing manure management strategies through small-plot research and wholefarm modeling

Plot-scale experimentation can provide valuable insight into the effects of manure management practices on phosphorus (P) runoff, but whole-farm evaluation is needed for complete assessment of potential trade offs. Artificially-applied rainfall experimentation on small field plots and event-based and long-term simulation modeling were used to compare P loss in runoff related to two dairy manure application methods (surface application with and without incorporation by tillage) on contrasting Pennsylvania soils previously under no-till management. Results of single-event rainfall experiments indicated that average dissolved reactive P losses in runoff from manured plots decreased by up to 90% with manure incorporation while total P losses did not change significantly. Longer-term whole farm simulation modeling indicated that average dissolved reactive P losses would decrease by 8% with manure incorporation while total P losses would increase by 77% due to greater erosion from fields previously under no-till. Differences in the two methods of inference point to the need for caution in extrapolating research findings. Single-event rainfall experiments conducted shortly after manure application simulate incidental transfers of dissolved P in manure to runoff, resulting in greater losses of dissolved reactive P. However, the transfer of dissolved P in applied manure diminishes with time. Over the annual time frame simulated by whole farm modeling, erosion processes become more important to runoff P losses. Results of this study highlight the need to consider the potential for increased erosion and total P losses caused by soil disturbance during incorporation. This study emphasizes the ability of modeling to estimate management practice effectiveness at the larger scales when experimental data is not available.

Evaluating the use of gel-based sub-sampling for assessing responses of terrestrial microarthropods (Collembola and Acari) to different slurry applications and organic matter contents

Microarthropods show considerable small-scale spatial variation, which on statistical grounds demands the use of numerous samples per experimental unit to obtain a representative density estimate. To avoid the identification of all individuals in these samples a sub-sampling technique is desirable. Due to various factors, existing sub-sampling methods perform sub-optimally when working with soil microarthropods. As an alternative, this study evaluated a gel-based sub-sampling method. The method was applied in a practical situation comparing effects of two existing methods of slurry manure application (injection of control slurry and the superficial application of slurry to which an additive was added) on soil inhabiting springtails and mites. In the experiment, special attention was paid to the mediating influence of soil organic matter content. The gel-based sub-sampling data showed a Poisson distribution, supporting randomness. Furthermore, none of the identified specimens showed morphological damage, strongly suggesting that neither gel-suspension nor amylase treatment had damaged the integuments of the specimens. Therefore, gel-based sub-sampling seems to offer an efficient and safe tool for sub-sampling microarthropods. Of the two slurry applications studied, the surface application of the slurry manure with the additive resulted in the highest abundances of microarthropods, with an average of 17,890 individuals m −2 in broadcasted fields, compared to 11,486 individuals m −2 in the slit injected fields. A positive correlation between microarthropod abundance and the organic matter content of the soil was found for the fields that were slit injected with unamended slurry. The specially prepared slurry treatment did not show the latter correlation, probably because of the a priori relatively high organic matter content of most fields receiving this treatment. The relative dominance of surface dwelling species in the superficially applied slurry with additive suggests that the microarthropods responded in particular to the method of slurry manure application rather than to slurry manure type.

Effects of slurry application methods on soil faunal communities in permanent grassland

We studied the effects of two slurry manure application methods, broadcasting manure slurry (MB) and manure slit injection (SMI), on soil faunal communities 1 week and 4 or 5 weeks after application in the spring of 2002 and the summer of 2003. No effect on total numbers of Enchytraeidae and nematodes was found. Enrichment opportunistic nematodes (CP1) significantly decreased in the MB treatment, resulting in a significantly higher Maturity Index. In the SMI treatment the Maturity Index was unchanged. Effects of manure application methods on earthworms depended on soil moisture and season. Under wet conditions abundance of earthworms, especially epigeic earthworms, decreased significantly in the MB treatment. In the summer of 2003 total earthworm numbers, and the fraction of epigeics, decreased after SMI. Due to the drought in this period, abundances of epigeic earthworms were already low and possible significant effects of the different manure application methods were therefore hard to interpret.

EFFECT OF PROPAGATION METHODS AND ORGANIC FERTILIZATION ON GROWTH AND CHEMICAL CONSTITUENTS OF OCIMUM BASILICUM L.,' SWEET BASIL.'

Two filed experiments were carried out during the twosuccessive years of 2004 and 2005) to study the effect ofpropagation methods (seedlings from seeds and terminal cuttings)alone or with using organic manure fertilizer such as farm yardmanure ''FYM'' or poultry manure ''PM'' at rates 0, 10, 20 and 30m3/ fed. on growth and chemical constituents of sweet basilplants. The obtained results indicated that, all growth parametersi.e., plant height, number of branches/plant, number ofinflorescences/plant, fresh weight of herb/plant and number ofroots as well as volatile oil percentage, oil yield per plant and perfeddan, N, P and K % and total carbohydrate contents in the herbwere significantly increased as methods of propagation such asterminal cuttings and organic manure application of poultrymanure. The best results were obtained from poultry manure atrate of 20 m3/fed. or farm yard manure at rate of 30 m3/fed. Alsocultivate terminal cuttings combined with organic manurefertilization gave the best results than seedlings combined withorganic manure fertilization. Terminal cuttings combined withpoultry manure gave the best results than other combines. Themaximum increment in the studied growth parameters andchemical constituents as well as yield and its component wereobtained by cultivate with terminal cuttings using medium rate 20m3/fed. from poultry manure or high rate 30 m3/fed. from farmyard manure at rate of 30 m3/fed. fertilization.

Rainfall timing and frequency influence on leaching of Escherichia coli RS2G through soil following manure application.

The time between swine (Sus scrofa) manure application to soil as a crop fertilizer, the first rainfall event, and the frequency of rainfall events should influence leaching potential of fecal pathogens. Soil microcosms were inoculated in the lab with a swine manure isolate of Escherichia coli, strain RS2G, expressing green fluorescent protein, to examine how timing and frequency of rainfall events influences RS2G leaching and survival in soil. Liquid swine manure inoculated with RS2G was applied to intact soil cores (20 cm in diameter x 30 cm long) 4, 8, or 16 d before the first rainfall event (50.8 mm over a 4-h period), and each core received one to three rainfall events. Manure application methods (no-till surface-broadcast, broadcast and incorporated, and tilled before broadcast) had no affect on leaching, although there was greater survival in soils when the manure had been incorporated. Most of the RS2G in the leachate appeared following the first rainfall event and RS2G leaching decreased with increasing time between manure application and the first rainfall, although leachates contained as much as 3.4 to 4.5 log colony forming units (CFU) 100 mL(-1) of RS2G when the first rainfall occurred 16 d after manure application. With increasing frequency of rainfalls there was a decrease in subsequent concentrations of RS2G in the leachate. There was no correlation between leachate RS2G and total coliforms or fecal streptococci concentrations. Soil RS2G numbers were 1 to 10% of the inoculum regardless of the length of time between manure application and the first rainfall. RS2G leaching was mostly influenced by the time between manure application and first rainfall event, and significant leaching and survival in soil was possible even if the first rain occurred 16 d after manure application.

Effect of rate, frequency and method of liquid swine manure application on soil nitrogen availability, cropperformance and N use efficiency in east-central Saskatchewan

A study was initiated in the fall of 1996 in the Black soil zone in east-central Saskatchewan (parkland region) to examine the soil and crop response to application of liquid swine manure at different rates, frequencies and methods of application. Low, medium and high rates of liquid swine manure (equivalent to approximately 100, 200 and 400 kg total N ha-1, respectively) were applied annually and in reduced frequency applications using injection and broadcast/incorporated placement over a 4-yr period. Crops grown during this period were Argentine canola (Brassica napus L.) in 1997, hard red spring wheat (Triticum aestivum L.) in 1998, hulless barley (Hordeum vulgare L.) in 1999, and Argentine canola in 2000. Under an annual application regime, a significant elevation of pre-seeding available N in the 0–60 cm soil depth and increased grain yield and protein content with increasing application rates of liquid swine manure were observed. Under a reduced frequency application regime, elevation of pre-seeding available N, grain yield and protein content observed in the year of application declined in the second year, and were significantly diminished by the third year. Cumulative N use efficiency (NUE) was highest (50–60%) for low annual application and lowest (10–30%) for high annual application rates that were injected. Generally, injection of liquid swine manure into the soil resulted in better enhancement of pre-seeding available N, higher grain yield and protein content, and better NUE than broadcasting and incorporation. Type of opener used to inject swine manure had no significant effect on either crop response or available N. This study showed that in the Black soil zone of the parkland region of Saskatchewan, annual application of low to medium rates (100 to 200 kg total N ha-1) of liquid swine manure are sufficient for high grain yield and grain protein, without leaving excess nitrates in the soil. In contrast, annual application of high rates (400 kg total N ha-1) of liquid swine manure has no agronomic advantage over the lower rates, but may result in higher residual nitrates in the soil, increasing potential for environmental pollution. Key words: Swine manure, N availability, manure management, N use efficiency

Influence of liquid manure application method on weed control in spring cereals

Summary Injection of liquid manure (slurry) into the soil is an alternative to the traditional surface application. By the injection method, it is possible to place nutrients closer to the crop sown, thus offering the crop a competitive advantage over weeds. This study compares the response in crop yield, weed density and weed biomass to injection vs. surface application of liquid manure through three growing seasons in barley and oats. The manure applications were combined with treatments of weed harrowing or herbicide spraying or no treatment at all. The levels of weed control and crop yield obtained by harrowing and herbicides were larger when slurry was injected compared with surface application. Without any weed control treatments, the injection method decreased the final weed biomass in barley. The influence of nutrient injection on yield and weed control seemed to be modulated by the time of emergence and the early growth rate of the crop relative to weeds. Thus, because of its early root growth and development, barley responded more quickly to the injection treatment than oats. Consequently, barley became a more competitive crop.

INTEGRATION OF LIQUID MANURE INTO CONSERVATION TILLAGE CORN SYSTEMS

Intensive cultivation and chemical fertilizer application resulting from traditional management practices insouthwestern Ontario, Canada, require high energy input and cause soil loss. Four field experiments were conducted overthree years in four mixed farms under notillage and minimum tillage corn (Zea mays L.) systems. The effects of fertilizersource and manure application timing, rate, and method on soil nutrient concentrations, corn grain yields, and groundwaternitrate concentrations were investigated. Three experiments included three basic treatments of fertilizer source: inorganic(chemical) fertilizer, liquid manure, and a combination of inorganic fertilizer and liquid manure. The other experimentincluded five treatments: preplant manure with and without incorporation by an aeration implement, sidedress manure withand without incorporation by a disc implement, and sidedress inorganic fertilizer.<br><br>Soil samples (0300 or 0600 mm depth) for analysis of soil nitratenitrogen (NO3N), phosphorus (P), and potassium(K) concentrations were taken periodically each year, including soil residual NO3N concentrations measured in the fall afterharvest. Weed biomass and corn grain yields were also measured. In general, higher NO3N concentrations were observedin those plots where nitrogen sources had been applied shortly before soil sampling. Trends of residual NO3N concentrationsvaried among experiments, and results were inconclusive. Twofold higher P concentrations were observed in the manuredplots than in the inorganically fertilized plots as a result of higher P2O5 inputs from swine manure. Farmers who apply liquidmanure to their notillage cornfields should be prepared for the possibility of additional weed pressure, especially usingpreplant manure application or sidedressing manure without a starter fertilizer. A 6% increased or comparative corn grainyield was achieved using liquid manure as a fertilizer source when weeds were not a problem. Considering the reduced riskof P runoff and the increased yield potential, the combined treatments, including preplant manure with sidedress inorganicfertilizer and starter fertilizer with sidedress manure, are recommended.

Cattle manure effects on structural stability and water retention capacity of a granitic sandy soil in Zimbabwe

The evaluation of soil aggregate stability and water retention is important in the assessment of soil management options. A 3-year study was conducted in 1999 to determine the effects of two cattle manure application methods on soil aggregate stability and water retention capacity of a sandy soil (Haplic Lixisol). Manure application increased soil organic C by 10–38% in the 0–10 cm layer. Compared with the control, manure management treatments increased the aggregate stability of soil as measured by the mean weight diameter (MWD) and aggregates between 2 and 10 mm (AGG2) indices from 0.243 to 0.733–0.926 mm, and from 27.3 to 128.3–148.3 g kg −1, respectively. The readily available water (RAW) capacity of the soil was significantly increased by manure addition, whereas the increase in AWC was not significant. The increase in water retention capacity in the soil was more affected at low suctions and this was related to the effects of manure on macroporosity. It was concluded that cattle manure was beneficial to the structural stability and water retention of this soil.

Using Linear Programming to Minimize Manure Storage and Application Costs in Pork Production

Various computer models have been developed to assist producers in planning manure and nutrient management programs. None of these models incorporates fixed costs associated with manure storage, hauling, and application. Current methods for calculating manure application rates require information such as nutrient content in manure, availability of nutrients for use as a fertilizer, and loss factors for different storage and application methods. The objective of this study was to develop a linear programming model that incorporates economic data on fixed and variable costs that can be linked to existing manure management computer models. An example with respect to swine (Sus scrofa) production is presented for various enterprise systems. As the size of the swine enterprise becomes greater than 150 sows, earthen lagoon storage and irrigation application becomes the optimal least cost method. Least cost storage and application costs for the 1200 sow operation was 63% of the least cost solution for the 150 sow operation. Within the same storage and application system, the 1200 sow operation had 77% of the per pig costs for a 300 sow operation. For enterprises with fewer sows, deep pit storage and injection application is the least cost choice.

Maize response to method and rate of manure application

Maize response to method and rate of manure application