Effect of treatment and application technique of cattle slurry on its utilization by ley: II. Recovery of nitrogen and composition of herbage yield

Abstract

The effect of slurry treatment and application technique on theutilization of nitrogen and on the composition of herbage was investigated onley in a 3-year field experiment on clay loam in southwestern Finland and onfine sand and Carex peat in northern Finland. Untreated, aerated or separatedslurry (liquid fraction) was applied on ley after the first cut by broadcastspreading, band spreading or injection into the ground. The application rate ofslurry was 33 to 62 Mg ha−1 and that ofammoniacalnitrogen about 80 kg ha−1. The highest recoveryofapplied nitrogen was achieved with injection. The apparent recovery of theammoniacal nitrogen of injected slurry varied from 23% to 50%, whereas that ofbroadcast and band-spread slurries was from 16% to 33% and 17% to 38%,respectively. However, injection did not result in any higher dry matter yieldthan the other application techniques, because it damaged the grass sward.Separation seemed to somewhat increase the recovery of slurry nitrogen, excepton peat soil, but the effect was significant for the apparent recovery ofapplied total nitrogen on clay loam in one year, only. Supplementing slurrywith 50 kg ha−1 of inorganic fertilizer nitrogenon clay loam increased both dry matter yield and nitrogen recovery by about onethird. Large amounts of potassium applied in cattle slurry raised the potassiumcontent and lowered the contents of magnesium and sodium in herbage on peatsoil. The reduction in calcium content was not significant. On clay loam, whichhad a higher potassium content than the peat, the general effect of potassiumapplied in slurry was weaker, but injection led to a higher potassium contentand lower contents of calcium and magnesium in herbage than surfaceapplications.