T. M. Harrigan

Predicting Suitable Days for Field Machinery Operations in a Whole Farm Simulation

Accurate information on the days suitable for field operations is important in the design, development, and selection of efficient machinery systems for crop production. The number of days suitable varies widely with climate, soil characteristics, and type of operation. This information is normally difficult to obtain for a given location. A model was developed to predict suitable day information from long-term weather records and soil characteristics of a location. This model forms a component of a farm model where it is used in the simulation of the timeliness, productivity, and costs of machinery systems in crop production. Optional output provides annual, long-term average, and 80% and 90% probable values for the days suitable each month. The model was verified to predict suitable day information similar to field observations for recent years in northwestern Indiana and similar to long-term historical data for a few other locations across the Midwest. The number of suitable days predicted each month was moderately sensitive to some soil characteristics and highly sensitive to the tractability coefficients used to determine a suitable day. Recommended tractability coefficients were developed for spring and fall operations on various soil textures. Usefulness of the model was further demonstrated by determining the 80% probable number of suitable days each month in central Michigan using conventional, mulch, and no-till systems on clay loam, loam, and sandy loam soils. Incorporation of the suitable day model into a whole-farm simulation model provides a useful research and teaching tool for studying the influence of weather on the days suitable for fieldwork, the performance of field machinery operations, machinery effects and interactions with other parts of the farm, and the economics of production systems.

Simulation to Evaluate Dairy Manure Systems

An existing dairy forage system model (DAFOSYM) was expanded to include submodels for manure production, collection, storage, and application to crop land. The original DAFOSYM simulated the growth, harvest, storage, and utilization of alfalfa and corn on a dairy farm over 25 years of weather. The revision allowed simulation of the quantity and nutrient content of manure produced as a function of feed composition and consumption, milk production, and animal growth. Nutrient losses in manure handling, storage, and application were subtracted to determine nutrients available for crop growth. The facilities, machinery, labor, and fuel required were modeled to determine the costs of manure handling. The integrated model provided a tool for evaluating and comparing the long-term performance and economics of alternative manure systems for dairy farms and their interaction with feed production. Manure systems using long-term storage with spreading, injection, or irrigation have greater direct costs to the farmer than the daily haul system commonly used in the upper midwest. If long-term storage systems are required to protect the environment, the annual net cost of manure handling will increase up to

SIMULATION OF DAIRY MANURE MANAGEMENT AND CROPPING SYSTEMS

65/cow for small (60 cow) and

TIME–MOTION ANALYSIS OF CORN SILAGE HARVEST SYSTEMS

45/cow for large (250 cow) dairy farms.

Net, Plastic, and Twine-wrapped Large Round Bale Storage Loss

The dairy forage system model (DAFOSYM) was expanded to include submodels for the prediction of suitable days under a range of soil and crop residue conditions, draft of a wide range of tillage and seeding implements, and scheduling of manure handling, tillage and planting operations. Through simulation, the long-term performance, costs and net return for three tillage and four manure handling systems were compared on 150 and 400-cow representative dairy farms in Michigan. The analysis included all factors of milk production including manure production, storage and application, tillage, planting, crop growth, harvest, feed storage, and feeding. Mulch-tillage was the most economical tillage system, returning

Economic Comparison of Liquid Manure Transport and Land Application

15 to

Draft relationships for tillage and seeding equipment

26/cow-yr over conventional tillage with a 30% reduction in machinery, fuel, and labor costs. The highest net return among manure handling systems was associated with short-term storage and daily hauling, but the economic advantage of this system diminished if credit was not given for the value of all manure nutrients when spread daily. Long-term manure storage concentrated labor for spreading in the spring and fall. This delayed tillage and planting and increased feed costs as much as

FIELD PERFORMANCE OF A LOW-DISTURBANCE, ROLLING-TINE, DRIBBLE-BAR MANURE APPLICATOR

24/cow-yr when manure hauling, tillage, and planting occurred in series. When labor and machinery were available for parallel field operations, manure handling method had little effect on the timeliness of tillage and planting.

Modeling Escherichia coli removal in constructed wetlands under pulse loading

Forage produced as corn silage is the primary feed for many dairies in the upper Midwest. Machinery costs in silage production represent a major cost of milk production. Many large dairy farms now use self–propelled forage harvesters with crop processors and truck–mounted dump boxes to transport chopped silage to bunker silos several miles from where the crop was grown. Farm managers, consultants, and others working with machinery management use equipment capacity information to estimate costs and select machinery to complete field operations within the time available. As new technology and information become available, a periodic study of on–farm activities is required to maintain current and useful information. A time–motion study of corn silage harvest on seven Michigan dairy farms was used to identify representative forage harvester throughput and cycle times, transport vehicle travel speeds, and time in maneuvering transport vehicles in the field and near storage. A typical harvester throughput ranged from 5.4 to 7.1 t–dm/h–row (6 to 7.8 ton–dm/h–row). When transport wagons drove alongside the harvester about 85% of the harvester cycle time was available for processing silage, and 15% for turning on the headlands and waiting for a transport vehicle. Truck– and tractor–drawn transport vehicles hauling to a bunker silo required about 7.5 min plus filling and road travel time for each cycle.

Soil electrical conductivity as a covariate to improve the efficiency of field experiments

Dry matter loss and quality changes were measured in large round alfalfa hay bales formed in a fixed chamber baler and stored six to nine months in East Lansing, Michigan. Four storage methods were compared: twine-wrapped bales stored in a shed on wooden pallets and twine, plastic, and net-wrapped bales stored outside on pallets. When removed from storage, twine and net-wrapped bales stored outside contained more moisture throughout than bales from the other two storage methods (p < 0.05). Dry matter loss averaged 6.0% in twine-wrapped bales stored inside and 9.6, 16.3, and 16.5% in plastic, net and twine-wrapped bales stored outside, respectively. Increases in neutral detergent fiber, acid detergent fiber, and acid detergent insoluble nitrogen concentrations were higher in the outer [10 cm (4 in.)] layer in net and twine-wrapped bales stored outside than in bales stored inside or wrapped in plastic (p < 0.05). Crude protein concentrations in the outer layer and all forage quality measures from the center of bales were similar across storage methods.