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Show V ESSENTIALS OF PLANT s Nitrogen, Phosphorus and Potassium Potas-sium Are Most Important. Sprlr-3 Plowing Under of Green Material Ma-terial in Orchard Interferes Greatly Great-ly With First Irrigation Two Eest Shade Crops. i (By R. S. HEKRICK, Colorado Experl- ment Station.) There are thirty-eight different chemical elements which are used to make up the growth of a plant. The following nine are .very essential for the proper development of the orchard or-chard plant: Carbon, hydrogen, oxygen, oxy-gen, nitrogen, sulphur, phosphate, potassium, po-tassium, calcium and iron. The three most important of these, and which are sometimes absent in available form, are nitrogen, phosphorus and potassium. A certain amount of nitrogen nitro-gen is required for the vigorous growth of the plant and is used principally in the formation of the woody part of the plant. Phosphorus Is not as essential in fruit growing as it is in the growing of grains, as It Is used to make up a large per cent, of the seed, but is, however, essential es-sential to aid the proper ripening of the fruit. Potassium aids in the mf proper coloring of the fruit and goes V to make up a large per cent, of the V ash of both the fruit and of the fruit J" wood. Many of our orchard soils are rich chemically in nitrogen, phosphorus and potassium, but oftentimes these elements are not available for the plant on account of the poor physical physi-cal condition of the soil; we mean that it lacks humus. By humus we mean the complete decay of organic matter which can be obtained hy the plowing under of some green manure crop, such as alfalfa, clover, vetch, oats, rye, etc. Jn the east where experiments have been run with clean cultivation versus sod for orchard soils, the results re-sults were found to be in favor of the clean cultivation. Clean cultivation culti-vation versus a rotational shade crop lias been tried in Colorado and the results were in favor of the shade crop rotation. In the east, cover crops are used, which means the sowing sow-ing of the seed in late summer and the plowing under of the green manure ma-nure crop the next spring or in the y1 early summer. Our conditions are J such that this method does not work 1 well, the greatest trouble being that .v". the spring plowing under of a great mass of green material interferes greatly great-ly with the first summer irrigation, as jt sometimes causes the soil to puddle and thereby causing the leaves to turn yellow. By shade crops is meant the sowing of the seed in the spring of the year, thus shading the soil during du-ring the summer from the sun, and the plowing under of the green crop either the following fall or the next fall, depending on whether , an annual, biennial or perennial crop is grown. Nearly all of the Colorado orchard soils are very poor In humus content' and this is the principal reason why thpy are so poor physically, that is, they are hard to work when it comes to . irrigation and cultivation, Such soils do not take water readily nor do they hold it after they have been k irrigated. .Humus in the soil will do A. away to a large extent with these troubles and can be obtained by the plowing under of barnyard manure, but on account of the scarcity of it, the orchardists will have to rely to a great extent, on the growing and the plowing under of a shade crop. Shade crops are divided into two classes, viz. leguminous and non-Iegum-inous. The legumes are plants like alfalfa, al-falfa, clovers, etc.; the non-legumes are the grains, like oats. rye. barley, etc. For orchard soils which possess a hard under soil there is no plant like alfalfa. This is not hard to handle if it is not allowed to go to seed and Is plowed under in the fall of the second year. It is well to sow oats, about one-half bushel to the ' ncre. with the alfalfa for a nurse crop. The oius should he cut before they go to seed and they can be harvested for food. Alfalfa can be sown later than clover with good results, but. as a rule. it. is better to sow all shade crops in the orchard as early in the spring as possible. Mammoth red clover clov-er makes a very good orchard shade crop, but sometimes It is hard to get the clover to grow well at first unless un-less it has the proper amount of moisture. mois-ture. This is one reason why clover is not always a success in peach orchards, or-chards, as sometimes the clover requires re-quires more water than is good for the peach trees. In growing anything in the orchard, one must remember that the trees are the first consideration and the crop of second importance. Far this renson do not over-irrigate the trees in order to get a good stand of clover, etc. |
