Swine waste lagoon effluent: its nutrient supplying potential and efficiency in corn production

Abstract

Field and laboratory investigations were conducted to evaluate the variability of nutrients in swine waste lagoons, to determine the effects of swine lagoon effluent on yield and nutrient concentrations of corn, and to study the downward movement of elements in surface applied effluent. Chemical analyses showed that elemental concentrations in effluent from the four lagoons varied. The lagoon that received the heaviest loading contained the highest concentrations of nitrogen, calcium, chloride, copper, manganese, phosphorus, potassium, and zinc.

Experimental results indicated corn grain yields were higher where 3.2, 6.4, 11.4, and 21.6 cm of effluent from a primary lagoon and 21.6 cm from a secondary lagoon as compared with the check treatment. Yield increases were explained by correction of either nutrient or moisture deficiencies. Plant analysis of corn ear leaf tissue indicated increased boron, manganese, phosphorus, and nitrogen concentrations and no difference in potassium, copper, and zinc concentrations from effluent application. Calcium and magnesium decreased with effluent application. This was attributed to dilution by increased growth and to the interaction between potassium and magnesium uptake.

Increases in electrical conductivity occurred in the lower depths where 21.6 cm of effluent was applied. The increase indicated downward movement of soluble salts. Of the exchangeable ions under study, only sodium increased in the surface soil with effluent application. It was concluded that continued application may lead to sodium buildups, unless it leaches from the soil. Biological and chemical analyses indicated that groundwater quality was unaffected in samples taken two months after final effluent application.