Many farm­ers would tell you that their pas­ture is some form of peren­nial rye­grass and clover.

Matamata Chronicle - - Rural Delivery - BY SUE ED­MONDS

But when tak­ing a close look at many pas­tures to­day you might be hard put to find the clover among the rye­grass. The clover seed went in with the grass seed, so where has it gone?

Part of the prob­lem may well be the pH lev­els. Clover thrives in sweet soils and there­fore re­sponds well to reg­u­lar ap­pli­ca­tions of lime. And when it pro­lif­er­ates in pas­ture it not only pro­vides a pre­ferred food source for an­i­mals, but it also does what clover does best, it takes ni­tro­gen from the air and tucks it away in nod­ules on its roots. Thus it ben­e­fits not only it­self, but also the soil and other pas­ture plants around it. But if urea is fre­quently ap­plied, then the clover gets dis­cour­aged and dis­ap­pears. As Dr Jim Crush of AgRe­search com­mented, clover is quite happy to switch off its bi­o­log­i­cal ni­tro­gen fix­a­tion and use fer­tiliser ni­tro­gen for growth, but clover can­not tol­er­ate shad­ing from ni­tro­gen fer­tiliser boosted grass growth. So of­ten the farmer puts on more urea to com­pen­sate, spend­ing money on a prod­uct which na­ture would have pro­vided for him, if the pH of the soil and sward man­age­ment had been right. Dave Mug­geridge of Tat­u­anui, who now ap­plies lime to his whole farm at 400kg/ ha ev­ery year, knows the pH of his soil is now at least 6.3, and the clover is thriv­ing ev­ery­where. He’s still a ‘ con­ven­tional’ farmer, but any urea used ( no more than 33kg/ ha/ yr) is only when the wrong weather slows down his pas­ture growth in mid- sea­son, and he needs some grass in a hurry. The sward in his pas­tures grows tall and very thick. There are none of the bare patches be­tween plants which are so of­ten seen else­where and al­most no weeds, be­cause there isn’t room for them to get es­tab­lished. And it’s not just the clover that is be­ing looked af­ter. Dave long ago re­alised that rye­grasses grow up­ward, putting out leaves at in­ter­vals along a stem. But he also found that there are never more than three grow­ing leaves on any stem, while those be­low them are dy­ing off. At this stage the pas­ture has reached its max­i­mum stand­ing crop and, although the rye­grass keeps on grow­ing, there will be no fur­ther in­crease in yield. Thus to get the best value from rye­grass, it needs to be eaten down, prefer­ably while there are only three leaves, or be­fore the lower leaves die off. This means that his cows get the best nour­ish­ment from it, and the pas­ture does not waste en­ergy re­plac­ing old leaves with new leaves. This en­ergy is bet­ter spent grow­ing the first leaves in the next crop of grass. This graz­ing strat­egy also means the clover does not suf­fer dam­ag­ing shad­ing from tall grasses. Jim Crush con­firmed that the key to main­tain­ing clover in pas­tures, es­pe­cially ni­tro­gen- boosted pas­tures, is get­ting them grazed be­fore the clovers are shaded out. By keep­ing his pH up, Dave can keep his urea bill down.

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