Economic Comparison of Liquid Manure Transport and Land Application

Abstract

A spreadsheet-based manure transport and land application decision tool, MANURE$HAUL, was developed to provide farmers, custom applicators, and others involved with manure management a manure cost and labor calculator for liquid manure systems using top-loading tank spreaders and nurse tanks. The manure hauling capacity was a function of the machinery set selected, manure tank capacity, and hauling distance. Manure transport and application costs were a function of spreader tank capacity and hauling distance. Representative 175-, 350-, 700-, and 1,400-cow dairy farms were compared to evaluate hauling time and machinery costs for a range of machinery sets, hauling distances, and nutrient values for the manure applied. Equipment ownership and operating costs were calculated for agitation, pumping, manure transport, land application, and incorporation. Equipment ownership and operating costs ranged from 0.32¢/L of manure hauled per year (1.18¢/gal) for a 175-cow dairy using a 11400-L (3000-gal) spreader with an average hauling distance of 1.6 km (1 mile) and broadcast application with tillage incorporation to 0.50¢/L (1.91¢/gal) for a 1400-cow farm with slurry injection and an average hauling distance of 6.4 km (4 mile) with two 34100-L (9000-gal) spreaders and four nurse trucks for over-the-road transport. Two nurse trucks supplying a tractor-drawn spreader became more cost-effective than two tractor-drawn spreaders alone at a hauling distance of about 4.8 km (3 mile). Injection application increased the number of days needed for manure application compared to a broadcast application with tillage incorporation, but when the time for tillage incorporation was included the total time needed for field operations with injection was less than broadcast with incorporation. Manure injection increased application costs about 6% compared to a broadcast application with tillage incorporation. When high soil phosphorus (P) levels restricted manure application rates to crop P removal rates, the credited nutrient value of the applied manure was reduced by 45%. The credited value of unincorporated manure with soil P constrained by crop removal was reduced by 60% compared to injected slurry with soil P at a build-up level. In each case the value of the manure nutrients applied exceeded the cost of agitation, pumping, transport, land application and incorporation.