Differential response of some cool season grasses to nitrogen, phosphorus and lime

Abstract

In a greenhouse experiment, yield and nutrient up take responses of seven cool season grasses to fertilization were compared on a red yellow "campo cerrado" soil, chosen because it was extremely deficient in N, P and lime. There was a significant variation between yieldsof species at low levels of fertility, and there was also a wide variation between species in magnitude of response to fertilization. Where no N was applied, Bromus uruguayensis Arech., B. auleticus Trin. and tall fescue (Festuca elatior var. arundinacea) yielded most, whereas orchard grass (Dactylis glomerota L.), rye grass (Lolium multiflorum Lam.) and harding grass (Phalaris tuberosa var. stenoptera) yielded the least (Fig. 1). Tall fescue, rye grass and B. uruguayensis were outstanding in their ability to utilize applied N for increased growth. B. auleticus was the species that responded least to applied N. In the uptake of N, there were less differences between species than in yield, except B. auleticus which took up less N where 200 kg/ha was applied than where 100 kg N/ha was applied (Fig. 5). Where no P was applied, tall fescue, rye grass and tall oat grass (Arrhenatherum elatius L. Presl.) were the three highest-yielding species, while E. uruguayensis, B. auleticus, harding grass and orchard grass grew least where no P was applied (Fig. 2). Applying P produced the greatest increase in tall fescue and rye grass and smallest increases in orchard grass, tall oats and B. auleticus. There was no difference in P uptake among the species where no P was applied (Fig. 6). At the 200 kg P/ha level, tall fescue, rye grass and orchard grass took up the most P. The two brome grasses took up least. At the 400 kg P/ha level, the relative positions of the species were the same except that orchard grass dropped below harding grass and tall oat grass. Where no lime was applied, B. uruguayensis and tall fescue made the most growth (Fig. 3). Applications of lime produced the greatest increases in tall fescue, rye grass and harding grass. B. uruguayensis made the least increase with the first increment of lime applied, and B. auleticus decreased with the second increment of lime applied. The uptake of Ca plus Mg was highest in B. uruguayensis where no lime was applied. At the 1000 kg Ca/ha level, B. uruguayensis and rye grass took up the most Ca and Mg, and tall oat grass and orchard grass took up the least. At the 2000 kg Ca/ha level, B. uruguayensis took up the greatest amount of Ca plus Mg, with rye grass and tall fescue next; orchard grass and B. auleticus took up the least. The interactions between varying levels of N and P, N and lime, and P and lime on the yield of two grasses are given in Tables 2, 3 and 4. The interactions between the nutrients differ between species. Table 5 indicates how two grass species vary in their response to Ca and Mg alone and in combination; responses to other treatments shown were similar.