Crop production, nutrient recovery and hydrology following cattle feedlot manure application

Abstract

A field plot experiment was established on a sandy loam Typic Natrustalf, duplex soil in Northern NSW, Australia in 1997, to determine crop response, nutrient recovery, and impacts on surface and subsurface water flow following the application of feedlot manure and effluent. Over the three year study, treatments included a control, (nil manure), moderate annual manure applications (20-25t DM/ha applied every year), a high initial application (60 t DM/ha applied in year 1 only) and an inorganic fertiliser treatment (N, P, K applied every year). Both the moderate annual and high initial manure treatments received supplementary inorganic N fertiliser in years 2 and 3. Successive forage crops of sorghum ('Sorghum bicolour' cv. Super-Dan) and triticale ('Triticosecale spp'.cv. Madonna) were grown with highest total dry matter yields recorded by the manure and inorganic treatments. The highest recovery of N, P and S was in the inorganic treatment (63%, 48% & 32%) and K from the high initial manure treatment (269%). Supplemental N applied to the moderate annual manure treatment tended to increase nutrient recovery mainly through increased yield. Total cumulative surface runoff ranked in descending order was control>inorganic>moderate annual>high initial manure treatment. The high initial manure treatment also recorded the lowest total cumulative subsurface flow (95mm) compared to all other treatments (mean 150mm).