Farm Management Under Irrigation

New Zealand Journal of Agriculture, Volume 63, Issue 5, 15 November 1941, Page 389

Farm Management Under Irrigation

Four Basic Principles Are Essential to Success

LtiiiiiiiiiiiiHiiiiiiiiniiiiiii By iiiiiuiiiiiiiiiiiHiiiiimius

A. A. COPLAND,

| Instructor in Agriculture, E 1 Timaru. |

* I ’WO small irrigation schemes al1 ready operate in South Canterbury, but within a . year or so large areas will be reticulated in Canterbury following the completion of the big Rangitata Works. These works are costly undertakings for so small a country, but while the initial cost is necessarily high, it will be considered small when the future advantages are - taken into account. If, however, the greatest advantages are to accrue from irrigation, the fullest possible use must be made of the water. This can be done only if at the very start we realise that the irrigation schemes were constructed in Canterbury for the sole object of supplementing a low rainfall. Many farmers view irrigation as a drought remedy only—that is, that the farms will not be made dependent on irrigation, but that the present system of dry land farming which has been evolved to fit into a natural environment will carry on and that irrigation will be called on only to tide over an unusually dry period.

It cannot be stressed too strongly that irrigation must not be viewed and adopted merely as a standby in times of a drought, and the farmer must realise this if he is to get profit, from the use of water. In Canterbury the ultimate aim should be farms of high production dependent on the continual use of water. The intensive use of irrigation will so increase the carrying capacity of the land that the stage will be reached where the water, in effect, becomes the life blood of the farms.

There are four basic principles about irrigation which the fanner must remember.

(1 Good Pasture Is Keynote to Success

The first step towards success in irrigationand this applies equally to farming in general— the - establishment and maintenance of good : pastures. In pastoral or agricultural farming the good grass and clover paddock is the keynote to success. It carries and fattens the sheep, it builds and repairs the fertility. In just the same way as it is false economy to spend good time and money in cultivation and then sow poor strains of grass and clover, so it is false economy to irrigate poorly-established and runout pastures. The greatest returns from expenditure on irrigation will result if the water is used to grow grasses and clovers and not weeds. This question of good pastures is of paramount importance, and if the

farmer is really to succeed he must pay particular attention to this branch of his farming. New Zealand has grasses and clovers of unrivalled persistency and high production, but these seeds are only to be found in sacks bearing a certification tag and seal. These are the seedsand these —which will give high producing and persistent pastures. At the same time, the sowing of first-class seeds will not be a guarantee to success unless equal attention is paid to cultivation and their establishment. It is like making a, chain, every link must be sound and able to take its full share of the weight. Point No.' 1, then, in developing a farm for irrigation is a good pasture.

(2) Consistent Programme x Of Irrigation

After the pasture is sown the next step in management on the dry plains land is to ensure that the pasture is not allowed to suffer reverses through lack of moisture. Without irrigation this is entirely beyond our control, but with irrigation the water can be applied at will. At all times the pas- 1 tures must be fed with sufficient soil moisture; they must never be allowed to wilt, brown off, and burn up.

Heaviest growth is produced by grasses and clovers on light silt loams when the soil moisture is 20 per cent, or greater. Soil moisture surveys carried out in Canterbury during the last six or seven years have shown the moisture content to drop as low as 4 per cent., often for long periods, which must never happen on the pasture

lands when irrigation is available. This means, therefore, that the farmer must adopt a programme of irrigation that is consistent, or, shall we say; persistent. It is a faulty practice to irrigate a paddock and then leave it until the plants are burnt up and nearly dead before applying further irrigation. This

very common mistake arises through the fault of viewing irrigation as , a standby for a drought. The true value of irrigation lies in the initiation and maintenance of high production, together with the building up of the food supplies and fertility of our soils. Past , farming practices on these light lands have resulted in the draining out of the ' inherent fertility, thus lowering the productiveness of the farms. Farmers have capitalised on this . fertility, and now they must put it back. With irrigation, not only can the farms carry more stock, but by the maintenance of good pastures and clovers (the clovers are essential) and by the passing of these pastures back per medium of the stock to the soil, i. the farm lands can once again be built up. This can be done only by following a consistent programme of irrigation. Once a farmer begins to irrigate he must follow it through. The cultivation entailed in constantly renewing (pastures is expensive, not to mention the cost of seeds and manures. If some of this money is now spent on water and the farmer ensures that the paddock does not become droughtstricken, then not only will the pastures produce considerably greater quantities of feed, but they will also hold for very many years longer.

(3) Control Stock On the Pasture

k The third important principle is that a plant lives not only by its roots but also by its leaves ,which perform the dual function of breathing and manufacturing plant food. This principle must be kept in mind when stocking the paddock. If too many sheep are crowded on to a pasture and left on too long,..the plants are severely pun-

ished, and inevitably they are weak' ' ened and lose vigour. A continuation of this practice results in their complete ruination. This overstocking of pastures occurs too often under irrigation, and again one is forced to the conclusion that it is the result of using irrigation as a drought measure only. The following is a common practice, and is essentially .wrong. Because of drought conditions more prolonged and severe than usual, the farmer becomes short of feed. He turns to irrigation as a way out, and the paddock is ditched and • irrigated. Immediately the grass begins to show green is just at a stage when it is recovering from a severe setback and requires careful nursing—on go the stock and they stay on. < A little later it may

rain, and the farmer is. through the drought, but the paddock is also through. A good pasture of ryegrass will stand heavy stocking, but. this stocking must be controlled and never at any stage carried to the extreme. As with a horse after a hard day’s work, a pasture requires a spell to build up, rejuvenate, and so make itself ready to carry on. While it is not my intention to discuss topdressing or the details of pasture management, it will be realised that if high production is called for, an adequate manurial programme must be carried out. What is taken out in the form of phosphate and other plant requirements must be put back.

(4) Gradual and Thorough Development

The development of a farm should be gradual and thorough. The farmer should start, say, with a small portion of his farm, having first prepared it for irrigation and sown it down. , If he now continues;to irrigate and carefully manages this pasture he will be growing more feed than he had in the past. He can then increase the number of his stock, but at the beginning and until he has gained considerable experience with irrigation, the farmer should always err on the conservative side. , With' the increased number of stock he will not be out of pocket for expenses for irrigation.

The whole aim is to bring about the change-over to irrigational farming gradually, using the gradual increase in stock and other returns to offset the cost of establishing the pastures, constructing races, and laying out the pad- . docks for watering. , This, means that in this development under irrigation the increases in acreage should coincide with the increase in stock or the equivalent of stock in extra crop for sale. At the same time, as more grass comes under irrigation, lucerne must be established so that hay can be cut to carry the stock through the winter. At present, one of the greatest difficulties facing the Canterbury farmer is shortage of feed in January, February, and early March. With irrigation, this gap can readily be bridged, but unless attention is paid to the winter feed problem the farmer will not receive the benefit, as his stock-carrying capacity is limited to that period of the year when his feed position is lowest. For this reason, a correct balance must be maintained between the area of pasture irrigated and the area of lucerne established to give the winter hay. . t Followed along sound lines and followed 1 consistently, irrigation cannot but help greatly to increase returns from farming, and at a profit. Irrigation in Canterbury is as yet in its infancy, but in every case at Redcliff and the Levels where the farmer has made consistent use of the water he has benefited greatly.

Conclusion Irrigation is the means of high production, but if this is to be achieved certain principles must be remembered. (1) A good pasture is the most valuable asset on the farm.. The pasture paddock is the manufacturer., of 95 per cent, of our stock foods. Its efficiency depends upon its composition. If greatest returns are to be obtained from irrigation every care must be taken to establish good pastures. It does not pay to water weeds. (2) Irrigation must be followed through; adequate soil moisture must be kept up to the plant at all times. (3) A pasture must be controlstocked and not overstocked. (4) Irrigation development must be gradual, a steady and thorough build-ing-up programme.