A comparison of the effects of liquid manure (urine and water) and nitrogen fertilizers applied to a grass-clover sward on soils of different pH value

Abstract

SummaryIn a 3-year plot experiment on a perennial ryegrass plus white clover sward the pH of the soil on the main plots was adjusted to, and maintained as nearly as possible at, target levels of 5·25, 6·00 and 6·75 by applying either sulphur or lime. Within the main plots the effects on herbage yield, clover content and crude-protein content of applying four fertilizers were compared at nitrogen rates of 225 and 450 kg/ha annually. The fertilizers were liquid manure (urine plus water), prilled urea, a urea solution and an ammonium-nitrate fertilizer. The applications of the urea and the ammonium-nitrate fertilizers were accompanied by dressings of a potassium fertilizer which supplied the same weights of potassium as in the liquid manure. On average the smallest yields of dry matter and crude protein were associated with the lowest soil pH with no significant interactions between pH and fertilizer treatment. The liquid manure gave slightly smaller total yields of mixed herbage dry matter than the other fertilizers, particularly at the low nitrogen rate. The herbage from the liquid manure treatment had a higher clover content and produced a greater total yield of clover dry matter. The effects of the liquid manure on the clover agree with those noted in previous experiments, but no evidence was found that these effects resulted from the liquid manure increasing the pH of the soil and improving the conditions for clover growth. Similarly, no proof was obtained that the clover effects were due to the nitrogen in the liquid manure being wholly in the ammonium form. However, the value of liquid manure as a fertilizer for grassland was demonstrated clearly.

Fertilization and Mowing Effects on Unimproved Mixed‐Species Hayfields in Quebec, Canada

“…Grass yields were not different when inorganic or manure fertilizers were applied in both hayfields, suggesting that similar yields can be obtained when decomposition coefficients and N‐loss factors are used to match inputs of manure N to inorganic N fertilizer. Our results are consistent with yields reported in grasslands that received the same N input from manure and inorganic fertilizer even though the P and K loadings differed (Min et al, 1999a, 1999b; Estavillo et al, 1996; Castle and Reid, 1987). The manure‐fertilized plots increased the P and K concentrations slightly compared to unfertilized plots in the Bromus – Poa hayfield, but statistical differences were not found in the Pleum – Lolium hayfield.…”

Effects of Cattle Slurry on the Growth Potential and Clover Proportion of Organically Managed Grass-Clover Leys

“…Other studies have shown less negative effect on the clover content by slurry than from an equivalent inorganic N fertilization (Dilz & Mulder, 1962;Castle & Reid, 1987;Chapman & Heath, 1987;Nesheim et al, 1990). The negative effect of inorganic N on clover may be offset by applying suf cient amounts of potassium (Chapman & Heath, 1987).…”

An analysis of environmental and economic implications of nil and restricted grazing systems designed to reduce nitrate leaching from New Zealand dairy farms. II. Pasture production and cost/benefit analysis

“…Numerous studies have shown that N applied as slurry or manure can reduce the clover content of a sward (Drysdale 1966;Castle & Reid 1987;Chapman & Heath 1988;Nesheim et al 1990;Estavillo et al 1996). Barr (1996), however, noted that even under high N use as fertiliser (400 kg N ha" 1 yr" 1 ) clover could persist, provided the sward is not permitted to re-grow more than 1200 kg DM ha" 1 between grazings.…”