Liquid manure as a grassland fertilizer. III. The effect of liquid manure on the yield and botanical composition of pasture, and its interaction with nitrogen, phosphate and potash fertilizers

Abstract

In a preliminary study of the use of liquid manure as a fertilizer for grassland in the summer, Castle & Drysdale (1962) obtained important increases in yield, an increase in the clover content of the sward and a reduction in the number of dicotyledonous weeds. In another experiment (Drysdale, 1964) liquid manure applied in February resulted, in July, in twice the content of clover that was obtained from a corresponding application of nitrogen and potash fertilizers. There have been a few reports in the literature of an increase in clover where liquid manure was used (Hendrick, 1915;Gisiger, 1950), but in general experiments have shown a depression of clover (Dusserre, 1933;Wheeler, 1958;Voisin, 1960) particularly with undiluted urine.The experiment reported here was designed to investigate in detail the effect of liquid manure on the yield of herbage and on the content of clover in the sward, and also the interaction between liquid manure and nitrogen, phosphate and potash fertilizers.EXPERIMENTAL,The trial was sited on a free-draining light to medium loam soil adjacent to the site of earlier experiments which showed a marked response to fertilizers containing nitrogen and potassium, but a negligible response to phosphorus. A sample of soil taken in January 1961 had the following analysis: pH 5-91, available P 2 O 6 6 mg./lOO g. and available K 2 O 20 mg./lOO g.A mixture of 20 lb. perennial rye-grass (S 24) and 3 lb. white clover (S 100)/acre was sown in May 1960 and produced an even sward with a good but not excessive development of clover. TreatmentsThe treatments applied were as shown at foot of next column.The fertilizer nitrogen was applied as 'NitroChalk' (21 % N), the phosphate as superphosphate (20-5 % P 2 O 6 ) and the potash as muriate of potash (60%K 2 O).The applications of liquid manure and fertilizers 22 were made in five equal dressings, the first in April and then after each of five cuts except the last. At each application the liquid manure treatments were applied first and were followed by the dry fertilizers.The liquid manure consisted of cow urine diluted with about three times its weight of water and was collected and stored during the winter. The mean contents of nitrogen in 1961, 1962 and 1963 were 0-32, 0-25 and 0-20% N and the corresponding values for potassium were 0-53, 0-42 and 0-37 % K; phosphorus was less than 0-01 % P. The weight of liquid manure to be applied was calculated to supply the correct weight of nitrogen. This entailed the application of potassium contained in the liquid manure and since it was not feasible to have liquid manure of constant potassium content there were small variations in the amounts of potassium put on at each application. The total weights of liquid manure and the nitrogen and potassium supplied per year in the liquid manure are shown in Table 1. Design and methodsSince this experiment was planned to investigate the interaction between liquid manure and Liquid manure LMO

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

“…However, it is relevant first to discuss the effects of the various fertilizers on the yields of herbage dry matter. Contrary to the results from an earlier experiment at this Institute (Drysdale, 1965), liquid manure gave, on average, slightly smaller yields of mixed herbage dry matter than inorganic fertilizers when both were applied in quantities calculated to supply the same weights of nitrogen and potassium. At combined nitrogen and potassium rates of 225 and 289 kg/ha respectively the mean annual yield of dry matter was 9-69 t/ha from liquid manure and 11-OOt/ha from ammonium nitrate plus a potassium fertilizer.…”

“…As in the earlier experiment (Drysdale, 1965), the clover contents of the mixed herbage and the clover dry-matter yields were greater with liquid manure than with any of the three inorganic nitrogen fertilizers, but the differences between the treatments were smaller. Thus, at the 225 kg nitrogen/ha rate the weighted mean clover content of the herbage dry matter over the 3 years was 9-7% with liquid manure and 2-4% with the ammonium-nitrate fertilizer.…”

“…As in the earlier experiments (e.g. Drysdale, 1965) the liquid manure consisted of cow urine diluted with washwater which was collected during the winter and stored until required. Before each application the liquid manure was analysed for nitrogen and potassium content and the weights required to supply nitrogen at rates equivalent to 45 and 90 kg/ha were calculated.…”

“…The present 3-year experiment was planned cow urine plus water, as a grassland fertilizer. For to investigate this hypothesis and also other factors example, Drysdale (1965) reported that similar which might contribute to the higher clover content weights of nitrogen and potassium applied either of herbage receiving applications of liquid manure, as conventional dry fertilizers or as liquid manure gave almost identical yields of herbage dry matter.…”

The effect of potassium deficiency on growth and N2‐fixation in Trifolium repens

“…Legumes are important in agriculture due to their ability to reduce atmospheric N 2 symbiotically within their root nodules, thus making it available for plants. It is well documented that legume growth and nitrogen (N) accumulation are extraordinarily responsive to K supply (Blaser and Brady 1950, Drysdale 1965, Duke and Collins 1985, Mengel and Steffens 1985. The impact of K deficiency on N 2 fixation is, however, not well understood.…”