Pasture Grasses Need Additional Nutrients to Furnish Livestock Ample Protein Supply
JUST AS GRASS is feed for the cow so she can give us proteins as well as fat and water in her milk, so must fertilizers be fed to the grasses so they can make the parts of the proteins which the cow passes on to us.
Plants make energy feeds readily; but they make protein feeds with difficulty. Carbohydrates as calorie- giving foods are synthesized, or put together, from the simple elements in air and water. The plant does this mainly through the energy effects of sunshine while but little is taken from the soil. But when it comes to making the proteins, even the plants seem to have trouble in supplementing their mineral needs from the soil for this function. They have been struggling to get proteins for themselves much as we have, then, in getting protein supplements for feeding our dairy cows and other livestock.
Since cows and other animals can get proteins only according as their feeds pass to them the constituent portions of proteins (called amino acids); and since plants, as we know for legumes, cannot make proteins on many soils without soil treatments, we can look at fertilizers as if they were protein and mineral supplements for the growing grass and thereby better as such for the cow.
One can put fertilizer on the pasture either in the early spring or in the late summer. Late summer is a good time to put fertilizer on the pasture to make future grass better. This is a good practice where the summer is apt to be dry and followed by autumn rains. Renovation of an old pasture by discing, fertilizing, and reseeding can well be done at that season when the grass is dormant. Relatively complete fertilizers according to soil tests, will build their nutrient elements into the grass at this time when this crop is not being pushed by the increasing sunshine power (as is true in the spring) to use all this to make more plant bulk, mainly carbohydrates.
Instead, with the shortening of the daylight period, the carbohydrates are manufactured into plant proteins and other storage compounds for reproduction. These will be carried over for rapid growth during the next spring when the sunshine intensity and length of day are both increasing to build plant bulk rapidly. Fall-grown grasses are, then, protein-rich feed for the cow so she too can build up a protein reserve on which to go into the winter.
Spring treatment as a top dressing is also good practice. The addition of nitrogen deserves attention then. Phosphorus, however, is taken more slowly. It is better when put into rather than on top of the soil. It should be down where the roots find it later in the moist soil. This does not move downward on its own solubility as the nitrogen does. It must be put down. Grass is just like corn and other summer crops. Its roots cannot feed in the dried surface soil.