The effects of stocking rate and nitrogen fertilizer on the productivity of irrigated perennial pasture grazed by dairy cows. 1. Pasture production, utilization and composition

Abstract

The effects of stocking rate and nitrogen (N) fertilizer on the productivity of irrigated perennial pasture grazed by dairy cows was studied for 2 years at Kyabram, Victoria. There were ten treatments: five stocking rates ranging from 4.4 to 8.6 cows ha-l at both 0 and 224 kg N ha-1 year-1 . Although weeds did not invade the pasture, increases in stocking rate resulted in reduced daily pasture growth, and this was related to the level of residual pasture after grazing. Annual pasture production in both years declined by 0.394 t DM ha-1 for every additional cow per ha. The levels of the herbage minerals, N, P, K, Ca, Mg and Na were adequate from an animal health point of view at all stocking rates, at least in the short term. The response to N fertilizer declined from 17 to 3 kg DM kg-1 N applied, as stocking rate increased from 4.4 to 8.6 cows ha-1, and it appeared that this response was due mainly to an increase in the growth of the grasses. Apart from the stocking rate responses, which are specific to the Kyabram environment, a number of relations were found, which showed how residual pasture after grazing, pasture allocation and pasture utilization at a single grazing, influenced pasture intake. Providing allowances are made for pasture type and the level to which any particular pasture type can be grazed, these relations could be expected to give a reasonable assessment of pasture intake in other environments.

Effect of high rates of nitrogen fertiliser on perennial ryegrass growth and morphology in grazed dairy pasture in northern New Zealand

“…Although no ryegrass measurements were made on these farmlets, the average increase in total herbage accumulation on farmlet HS400 was only 1% greater than the increase in herbage accumulation on farmlet HS200 and so N response was lower than on the corresponding lowstocked farmlets. A lesser response to increasing rates of N at higher stocking rates was also reported by Stockdale & King (1980) who suggested it was because of lower average pasture residuals limiting regrowth at high stocking rates.…”

Scope to improve phosphorus (P) management and balance efficiency of crop and pasture soils with contrasting P status and buffering indices

“…Farm-gate data for 339 enterprises and an additional 437 records data for specific products were drawn from a number of sources (Ayers et al 1977a, b;Southwood et al 1976;McCaskill and Cayley 2000;Chapman et al 2003;Li et al 2006;Simpson et al 2010;Burkitt et al 2007;Russell 1960;Cannon 1969;Morley et al 1969;Curll and Smith 1977;Lloyd Davies et al 1998;Waller et al 2001a,b;Holst et al 2006;McGregor 2010a,b;Stockdale and King 1980;King and Stockdale 1980;Cowan et al 1995;Curll 1977;Carter and Day 1970;Ovens et al 2008;Weaver et al 2008;Bell 2009). For the 339 enterprises, there were 159 farm-gate budgets for beef, 78 for dairy, 28 for mixed cropping and grazing, 7 for cropping and 67 for sheep.…”

Identifying management strategies to improve sustainability and household income for herders on the desert steppe in Inner Mongolia, China

“…Some research shows that increasing stocking rate can improve pasture utilization and pasture quality in farm system (Baker and Leaver, 1986;Fales et al, 1995;Holmes and Parker, 1992;Macdonald et al, 2008;Stockdale and King, 1980), but most research shows that continuous higher stocking rate leads to reduction of the net income of herders and this impacts the development of all animal husbandry practices (Eigenraam et al, 2000;Jia and Wang, 1994;Michalk et al, 2003;Rittenhouse and Roath, 2002;Tilman and Downing, 1994;Tilman et al, 1996). It is difficult to find the effect of stocking rate on animal production and economic benefits (McCollum et al, 1999), but values for the vegetation and soil are easier to find based on the condition of the grassland.…”