C.H. Noller

Influence of nitrogen, phosphorus, and potassium fertilization on the mineral concentrations in Medicago sativa L. I. Seasonal changes 1

Abstract An established stand of Ranger alfalfa was topdressed with equal rates, but different combinations, of N, P, and K. Five harvests were taken and the material analyzed for cation concentrations. Phosphorus application significantly increased P concentrations in alfalfa, but had little influence on concentration of other ions. Potassium applications showed striking effects by significantly increasing K levels of the forage while decreasing Ca, Mg, Cu, Zn, Al, and Mo levels. Significant differences occurred among harvest dates for 14 of the 16 cations analyzed. Seasonal trends were evident for SiO2, Zn, Al, Co, and Na. Applied N, P, and K and available soil P and K were associated with cation concentration of alfalfa and these interrelationships are discussed.

Influence of nitrogen, phosphorus, and potassium fertilization on the mineral concentrations of medicago sativa L. II. Diurnal and day to day fluctuations 1

Abstract An established stand of alfalfa was fertilized with different combinations of N, P and K. The rate used per nutrient was constant for all combinations. The study was conducted to evaluate the effect of fertilizer application, diurnal change and period to period fluctuation on the mineral composition of alfalfa. Two experiments were conducted at different stages of morphological maturity. Experiment one (E‐1) was initiated when regrowth after an initial hay harvest was in the late‐vegetative to early‐bud stage. The second experiment (E‐2) was initiated when regrowth from E‐1 was approximately 20 cm tall. Phosphorus application significantly increased the P concentrations in alfalfa, but decreased the Cu levels in both experiments. Potassium applications significantly decreased the levels of Ca, Mg, Na, Cu, Zn, Mo and Co. Levels of all minerals analyzed in E‐1 were significantly different from period to period while only seven of the sixteen were significantly changed in E‐2. Period to period diffe...

Influence of NPK fertilization on calcium and magnesium in Poa pratensis L. with reference to dietary requirements of grazing cattle

Abstract A two‐year experiment was conducted on Edwards muck (Limnic Medisaprist) on the Pinney‐Purdue Agricultural Center at Wanatah, Indiana to study the effect of NPK fertilization on Ca and Mg concentrations in Kentucky bluegrass (Poa pratensis L.). Eight combinations of N‐P‐K fertilizer (0–0–0, 0–99–0, 0–0–372, 0–99–372, 168–0–0, 168–99–0, 168–0–372, 168–99–372 kg/ha), were applied each spring. Four cuttings were taken annually during the 1979 and 1980 growing seasons from a 1.5 m2 caged area. The Ca concentration in the forage ranged from 0.31 to 0.64% and the Mg concentration from 0.18 to 0.34%. Application of 168 kg/ha N and 99 kg/ha of P applied together resulted In the highest Ca concentration in the forage for each of the four cuttings. However, N and P applied alone had little if any effect on Ca concentration. The application of 372 kg/ha of K significantly decreased Ca (LSD ≤ 0.05) throughout the growing season. Magnesium levels in the forage were Increased by N fertilization and decreased b...