A study of the interaction of P, K, S, Mg, Mo, and B fertilisers, and ground limestone, applied to grass-clover pasture

Abstract

Results are presented of two multi-factorial field experiments on permanent pasture with six fertilisers and ground limestone. The trials were carried out at Marton Experimental Area and at Invermay Research Station, Mosgie!. Treatments were: -high versus low rates of ground limestone, muriate of potash, and double superphosphate; and some against nil rates of elemerrta'l sulphur, magnesium carbonate, borax, and sodium molybdate.All treatments except limestone and sodium molybdate were applied annually by 'top-dressing.The main effects and two-factor interactions of these seven treatments on yield, concentration of nutrients in the pasture, herbage composition, and soil quick tests, were determined with considerable accuracy. Yields were affected by negative LMo, LP, LMg, MgP, and LMoB, and by positive LK, SK, and BP interactions. The negative interactions were the results of two or more treatments acting in the same direction. Heavy liming increased the availability of molybdenum and of phosphorus as measured by plant uptake and dry matter yields. Magnesium carbonate slightly raised soil pH and acted simiilarly to lime on molybdenum availability. It did not increase phosphorus concentration in plants, but it increased the yield responses on the low phosphorus plots at Marton. Positive interactions generally resulted from simultaneous corrections of deficiencies or toxicities. At Marton yield responses to muriate of potash were increased by an adequate supply of sulphur and by heavy liming. Borax raised yields occasionaHy on the high phosphate plots, but tended to depress yields on the low phosphate plots. The concentrations of N, P, K, Ca, Mg, Na, Mn, Mo, B, and eu in the pasture were influenced by treatments, many interactions taking place.The results of these trials indicate rhe importance of balancing fertiliser and lime applications correctly to give maximum returns; they also indicate new lines of investigation in the fie1d of soil fertility and pasture growth.

Fertiliser and lime effects on some southern North Island hill pastures

“…This, combined with the extremely heterogeneous nature of the hill slopes involved, resulted in a rather imprecise definition of individual site responses to Mo and ON. The herbage nutrient values obtained indicate that herbage levels ofK, Mg, Cu, and Mn were not limiting legume vigour; however, N and P levels were low, and indicate possible deficiencies (Wells 1970, McNaught 1970, During et at. 1960, Andrew & Hegarty 1969.…”

Effect of potassium fertiliser., soil magnesium status, and soil type on uptake of magnesium by pasture plants from magnesium fertilisers

“…Of course, if dolomite increases the proportion of clover to grasses, it will increase Ca concentrations in the mixed herbage, but this can occur only if the soil pH is too low for optimum growth, especially if clovers are molybdenum-deficient, if clover growth has been restricted by true magnesium nutrient deficiency, or if insufficient phosphate has been used (During et al 1960: see Marton Interaction, Tables 12 and 16) .…”

“…In this context, McNaught's (1960) experiment is largely irrelevant, as it was carried out in the absence of grazing animals, under grossly exaggerated and artificial conditions with drastic and rcpeated crop removals and use of unbalanced fertiliser designed deliberately to produce a soil with extremely severe potassium deficiency. The primary purpose of that experiment was to demonstrate the differences between plant families or genera in their adaptation to potassium deficiency, not to show the effects of K fertiliser on levels of other cations under practical farming conditions.…”

Effects and interactions of phosphorus and sulphur on a mown white clover/ryegrass sward

“…The multi-rate factorial trial design allowed conclusions to be drawn regarding optimum nutrient rates and indicated that the S content of SSP was more than adequate (in relation to the P content) in conditions similar to those of the trial on the Lismore soil (Lammerink 1962). During et al (1960) presented results from two multi-factorial field trials examining the interplay of various fertiliser and lime treatments on pasture growth; many nutrient and lime interactions, both positive and negative, were observed, emphasising the importance of balancing fertiliser and lime applications correctly to give maximum returns. McNaught (1973) and Middleton(1973Middleton( ,1980Middleton( , 1983 have also emphasised the importance of nutrient balance in pastures.…”