Covered storage reduces losses and improves crop utilisation of nitrogen from solid cattle manure

Abstract

A 2-year study was carried out to examine the effects of solid cattle manure storage method on (1) total carbon (C) and nitrogen (N) losses, (2) first-year and residual manure dry matter (DM) and N disappearance after litterbag placement on grassland, and (3) apparent herbage N recovery (ANR) after a single surface application to a sandy grassland field. About twelve tonnes of fresh (FRE) manure taken from a litter barn were stored per treatment as stockpiled (STO), composted (COM) and covered (COV) heaps for 130 days, and total C and N losses were estimated. Thereafter, patterns of DM and N disappearance from FRE, COM and COV manures were monitored using litterbags with three mesh sizes (45 μm, 1 mm and 4 mm). Herbage ANR from these manures was measured at application rates of 200, 400 and 600 kg N ha−1. During the storage period, only about 10 % of the initial Ntotal was lost from the COV heap, whereas these losses were 31 % from the STO heap and 46 % from the COM heap. The respective Ctotal losses were 17, 59 and 67 %. After field placement, overall manure DM and N disappearance rates from all mesh sizes of the litterbags were in the order: COV > FRE > COM (P < 0.05). Independent of N application rate, total herbage ANR was the highest from COV and the lowest from COM manure over two growing seasons (23 vs. 14 %; P < 0.05). Including the N losses during storage, an almost three times higher herbage ANR (20 vs. 7 %) of the manure N taken from the barn was observed by using COV versus COM manure. In case of FRE manure this ANR fraction was 17 %. It is concluded that COV storage reduced storage C and N losses to a minimum. After field application, manure stored under this method decomposed faster and more N was available for plant uptake, especially when compared to COM manure.