Effects of sodium and potassium fertilisers on the composition of herbage and its acceptability to dairy cows

✍ Scribed by Chiy, Paul C; Al-Tulihan, Abdul-latif A; Hassan, Mohammed H; Phillips, Clive J C

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 272 KB
• Volume: 76
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199802)76:2<289::aid-jsfa959>3.0.co;2-l

✦ Synopsis

Fertilisation of herbage with Na can increase acceptability to cows, but the inÑuence of fertiliser rate and fertilisation by K is unknown. In experiment 1, ten cows were grazed on pasture plots that had just been fertilised with 0È132 kg-Na ha~1 (current Na) and had received 0È64 kg-Na ha~1 in the previous grazing season (residual Na). Herbage Na concentration increased in proportion to current Na from 2É7 to 4É9 g-Na kg~1 dry matter (DM) and also increased with increasing residual Na from 2É2 to 4É5 g-Na kg~1 DM. Herbage K concentrations were low (10 g kg~1 DM at 0 kg-Na ha~1) and were only slightly reduced by Na fertiliser. Herbage Mg and Ca concentrations and DM digestibility were maximum at 66È99 kg-current-Na ha~1. Cows grazed current-Na-fertilised plots to a lower height and spent more time grazing them. In experiment 2, pasture plots received no fertiliser, low and high isomolar and independent applications of Na and K or a combination of the two. The herbage was more mature than in experiment 1 and Na concentration of the herbage without Na fertilizer was high (5 g kg~1 DM). Na fertiliser, therefore, only slightly increased Na concentration, more in clover than in grass, and had little e †ect on K concentration. K fertiliser increased K concentration from 16 to 20 g kg~1 DM and reduced Na concentration to 3É5 g kg~1 DM. Sodium fertiliser, therefore, only increased the acceptability of herbage to cattle when herbage Na concentrations were initially low (less than 5 g kg~1 DM) and were increased substantially by the application of the fertiliser.

1998 SCI.