The effect of fertilizer nitrogen, phosphorus and potassium on the calcium, magnesium and phosphorus status of pasture cut for silage

Abstract

Physiological problems in some Fife dairy herds were thought to be associated with mineral imbalance in grass cut for silage. Consequently trials at two sites were conducted to study the effects of three levels of nitrogen and phosphorus and two levels of potassium on yield and composition of pasture cut for silage.Nitrogen increased yield of herbage and reduced its clover content whereas phosphorus and potassium had little effect on yield or clover content. Herbage clover content and calcium concentration declined over the period of the experiment. Mean concentrations of calcium, magnesium and phosphorus were 5-8, 1-7 and 3-4 g/kg respectively. Concentrations of these minerals varied more with time of cutting and with season than with level of applied phosphorus and potassium.Nitrogen tended to reduce calcium concentration in mixed herbage and to increase magnesium concentration in the grass component; it did not affect herbage phosphorus concentrations, but narrowed the calcium-phosphorus ratio in the second cuts. Applied phosphorus increased herbage phosphorus concentration only at the site with the lower soil phosphorus status. Potassium tended to reduce magnesium concentration in clover and, at one site, in mixed herbage; it also tended to reduce herbage phosphorus concentrations in second cuts.Mineral uptake was increased by applied nitrogen. Mean annual uptake of calcium magnesium and phosphorus was 34, 10 and 20 kg/ha respectively.The effects of treatments on concentration and balance of these minerals are discussed in relation to ruminant requirements and maintenance of suitable levels of the minerals in the soil.It is concluded that normal applications of NPK fertilizer are not detrimental to satisfactory mineral balance in pasture.

Application of Different Rates of N:P:K Fertilizer on the Growth and Yield Components of Upland Rice in Rice-Soybean Intercropping System

“…However, 400 kg N:P:K gave consistently the highest leaf area index of soybean at 6 and 8 WAP in both cropping seasons. This is consistent with studies by [28,29,30,31,32], who reportedly established that increasing the fertiliser rate statistically increased the leaf area index of soybean while it is in disagreement with the finding [33] who noted a decrease in leaf area index of soybean as a result of an increase in Nitrogen fertiliser application. The interaction of soybean and fertiliser consistently showed significant differences in the leaf area index of sole soybean in both years (Table 9).…”

The effect of rejuvenation of Aspen Parkland ecoregion grass–legume pastures on dry matter yield and forage quality

“…The interaction effects of year × site, year × fertilizer and treatment × fertilizer were all significant (P < 0.05) over the 3-yr period. Due to non-homogeneity of variances (Bartlett's test, Steel et al 1997) between site-year, and treatment × year interactions, the experiment was analyzed separately for each site-year combination. Whole plot and split-plot means were tested for differences using Fisher's protected LSD test (Steel et al 1997).…”

“…Forage Ca content was also lower in samples from the second and third years at the unmanaged DNC site. Applying N fertilizer to grass-legume swards reduces the Ca concentration of mixed forages due to a depression in the legume content of the mixed pasture (Rodger 1982). However, burning increased Ca content of forage at Pathlow (Gray Wooded site) from 6.4 g kg -1 in year 1 to 12.1 g kg -1 in year 3.…”