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Show Fertilizing Through Irrigation Wafer Using the irrigation system to spread fertilizer fer-tilizer is an appealing idea and it has certain merits, but it is no panacea. Certain complicating com-plicating factors severely se-verely limit the use of this practice. Be sure you can satisfy sat-isfy the following exacting exact-ing requirements before you decide to put fertilizer fer-tilizer in your irrigation irriga-tion stream or through your sprinkler system: 1. Select fertilizer thit will dissolve quickly quick-ly and completely in the water. This usually eliminates' phosphates, potash, and trace element ele-ment materials. 2. Make sure the fertilizer fer-tilizer you add will not form a precipitate with the minerals contained in the water. This is particularly serious it you apply fertilizer through a sprinkler system. sys-tem. 3. Avoid losing the fertilizer into the air as a gas. This is a critical problem if an hydrous or aqua ammonia ammo-nia is added to water that has a high pH. It can happen also in some situations when these materials are on the soil surface. 4. Make sure the irrigation ir-rigation system distributes distri-butes the water evenly. The distribution of fertilizer fer-tilizer cannot be any more uniform than the distribution of water. 5. Don't allow the water wa-ter to run off from the area being irrigated. When fertilizer is dissolved dis-solved in the irrigation water, it will move off the field in the runoff. This can present a pollution pol-lution problem. In contrast, con-trast, fertilizer that is "spread directly onto the soil surface will generally gener-ally move into the soil and not be lost in runoff. Of course, if there is soil erosion, fertilizer in the eroding soil will go off in the runoff. 6. Make sure the fertilizer fer-tilizer is of a kind that does not corrode the irrigation ir-rigation equipment. Nitrogen fertilizers are the most feasible for water application. Of various nitrogen fertilizers, fer-tilizers, urea seems to offer certain advantages in meeting the requirements. require-ments. Often it is advisable ad-visable to apply nitrogen two or more times during dur-ing the growing season. Injection into the irrigation ir-rigation water could facilitate fa-cilitate fertilizer application appli-cation topastureorturf. Also, application in irrigation ir-rigation water can prevent pre-vent crop damage from ground equipment. Nitrogen Ni-trogen needed on grain or corn during the growing grow-ing period is a good example. The fertilizer can be added to the irrigation ir-rigation stream and eliminate moving equipment equip-ment through the crop. We discourage the use of anhydrous ammonia or aqua ammonia through sprinkler systems. sys-tems. If the pH of the water exceeds 8, losses of ammonium into the air will be high. This is particularly critical in hot weather. In addition, ammonia applied in an irrigation stream can pass into the air from the soil surface. Since the superphosphates superphos-phates do not dissolve readily, phosphoric acid is more suitable for water application. But phosphoric acid is corrosive. cor-rosive. Since crop phosphate phos-phate needs can be satisfied sat-isfied with only one application ap-plication in two or three years, it usually pays to spread it directly on the land. Potash fertilizers are generally more soluble than the phosphates, but some commercial grades of potash are not soluble enough to be satisfactory. Furthermore, Further-more, potash is rarely needed in the dry areas of the West. Where it is needed, it usually is more practical to spread with ground applicators.. ap-plicators.. Trace elements applied ap-plied to irrigation water usually form precipitates precipi-tates in the water. Since I they are not needed 'more often than once in years, they can be applied ap-plied directly to the soil. Trace elements, potash, po-tash, and phosphates can be applied in irrigation water if a water conditioner condi-tioner is inserted into the stream ahead of the fertilizer nutrients. Use of a water conditioner, however, is expensive and may not be economically econo-mically feasible. When we consider the complications involved in meeting the exacting requirements for satisfactorily satis-factorily applying fertilizer fer-tilizer in irrigation water, wa-ter, we recognize that it is no panacea. Frequently, Fre-quently, it is much easier and more practical prac-tical to spread the fertilizer fer-tilizer with ground equipment. This is especially es-pecially true with phosphate, phos-phate, potash, and the trace elements. |