Merits Of Spray Irrigation At Eiffelton

Press, Volume CVI, Issue 31125, 30 July 1966, Page 8

Merits Of Spray Irrigation At Eiffelton

An Eiffelton fanner who has been spray irrigating for ten years believes that he has obtained an average annual return of 50 per cent on his capital investment.

Addressing a forum i on spray irrigation’ ® held in Christchurch this week, Mr J. R. ( Cocks, who was a 1 Nuffield scholar in 1 1964, said this figure , could only be an estim* - ate, but it was based r on 10 years* observa- t tion and experience, ’ and he believed it was t close to the mark. t Mr Cocks was one of three farmers who spoke on the s benefits of spray irrigation, t both from the point of view s of production, and financially. Mr Cocks farms a 400-acre t property comprising 220 acres t of heavy land and 180 acres < of light to medium land. His I programme, until a few years ] ago, had been one-third arable i cropping, one-third seed pro- I duction, and one-third grass- i land, but he said experience < ■ had gradually led him to vary ’ the programme to one of 45 1 to 50 per cent arable crops, 1 30 per cent seeds and 20 to ! 25 per cent grass. ! His irrigation plant is a ( direct-coupled unit capable of delivering two cusecs of water through up to 29 chains of 20ft pipes, mainly sin, and operating 30 to 40 sprinklers at 40ft intervals. The average pumping rate is 500 to 600 gallons a minute, pumping mainly from creeks, but there are also two bores on the light land, one of which yields 250 to 300 gallons a minute. “We apply three to four Inches of water at each irrigation, moving the plant an average of 70ft,” Mr Cocks said. “This involves three shifts a day of four to five hours’ duration." £6 An Acre Irrigation coverage has been obtained for all but 50 acres of the entire property at a capital cost of £6 an acre. Twelve months ago Mr Cocks purchased additional land, which is also being extensively irrigated by a second plant of slightly larger capacity, and the capital cost has been £7 an acre. This involved considerable diversion of existing creeks to give better reticulation, some realignment, and also complete removal of fences to improve design so that the entire layout, the planning of crop rotations, and every management decision, hinges round the use of the irrigation plant Discussing the question of where small seeds fit into ■R such a programme, Mr Cocks » said that for the last eight | years he had averaged 800 hours pumping a year, applying three to four inches of 2 water to 275 acres, but as his b appreciation of irrigation had grown, he was making greater use of it each year. For instance, two seasons ago, 453 acres were watered, and even during this last very favourable season, the homestead plant watered 331 acres. 5, These were total figures; in both cases 260 acres were watered, and up to 140 acres 0 of that area twice or more—u perhaps once as a seed crop and again for autumn-saved pasture. “We have now reached the ■ stage where irrigation is a 1 routine practice, and the more the rain helps us the better J we like it,” Mr Cocks said. - With few exceptions, all seed crops on Heatherlea are watered. Irrigating small seed crops had brought higher average yields. Since he began to apply ■ water to the light land block, ' Mr Cocks has raised his average yield of ryegrass by 15 bushels an acre. As well as achieving higher yields, he k has been able to devote a > greater area of that land to I seed production—even cocks- ■ foot seed production, where

previously this was not considered to be sound economically.

Giving an example, Mr Cocks told the forum that in 1964-1965 season, he turned the sheep back into 25 acres of ryegrass seed on a light land paddock that he was unable to water, not because he needed the feed, but because the seed crop had literally withered away. Two paddocks away, where he was able to apply water, he dressed 53 bushels of ryegrass to the acre, at that time worth 25s a bushel, and he also obtained 100 bales of straw to the acre. This was sold for 2s a bale.

“I would emphasise that this is an extreme case. It is the average over a number of seasons that really counts, but I cannot overstress the value of higher average yields in achieving maximum net profit,” Mr Cocks said. “It must never be forgotten that a 25 per cent increase in yield can mean a 100 per cent increase in profit, and a 25 per cent Increase in yield is not difficult to obtain with an irrigation plant. “We obtain full value for every penny we spend on

nitrogen. This was a breakdown point. In the past we did not always obtain full benefit from nitrogen, particularly on the light land in a dry year. Now we use it with certainty,” Mr Cocks said. Mr Cocks said he wished to point out that he considered the two key factors in attaining really high production in Canterbury were water and nitrogen, whether by way of clover pasture, or out of the bag, and this field warranted further research. Mr Cocks has found that spray irrigation has enabled him to close his paddocks later. This was what he termed another breakdown point “If we closed too early on the heavy land, we were in trouble,” he said. “If we closed too late, we could on occasions, seriously deplete the yields. If we grazed our cocksfoot too hard in the autumn, it could suffer in a dry spring. Now we know where we are going.” For example, he said, last year from an Hl paddock sown immediately after two wheat crops, the early August lambs were drafted before the paddock was closed for seed, and one third of them were taken at an aver-

age of 331 b. The paddock was watered, and eventually yielded 47 bushels an acre after suffering heavy rain damage in the windrow. The paddock received lewt of nitrogen. Mr Cocks harvested one paddock of Timothy for five consecutive seasons, and drafted two-thirds of the lambs and the ewes before closing for seed each year. This same practice applied equally to white clover seed production. This sort of thing was not considered possible before irrigation. It had also been possible to plough a proportion of the spring cropping ground as late as September, and even October. Mr Cocks said all this meant that he could make management decisions he would not otherwise have made, even though he did not always have to use the plant. In 1958, one watering of barley undersown with Government Stock cocksfoot, both lifted barley yields and saved the cocksfoot from dying during a dry spell. Mr Cocks said reliable establishment of seeds after crop'on the peaty

loam, was a serious problem years ago. Now it was no longer a problem. Mr Cocks said it was usual practice to water the cultivated ground thoroughly, work the paddock again, then drill, but on the light land, he often drilled first, then watered. Moderate crops of turnips had been grown with ryegrass seed established in this way immediately after a grain crop. He said he was also able to establish seed, plus turnips on the light land with absolute certainty, after a very short summer fallow, so eliminating yet another break-down point

The ryegrass paddock mentioned earlier was sown with turnips in the very dry autumn of 1964 at the normal time and watered after drilling. The whole district waited until the middle of February to drill, but the rain still failed to materialise. The excellent crop of turnips that he obtained enabled him to sell a large quantity of hay at drought prices. By watering some grass paddocks in the spring, Mr Cocks said he had been able to maintain his sheep on a smaller area, thus making more land available for cropping and seed production. Watering of seeds had brought about more autumn

feed and better clover content in the resulting pasture, particularly when these paddocks were watered again after harvest. Irrigation had given considerable scope for management in obtaining maximum results from seed and crop production, and at the same time carrying maximum numbers of sheep. Mr Cocks said however, that all his achievements had not been plain sailing. “We have made mistakes, mainly in watering too late,” he said, “or in not watering when we should have. “We have blown up our plant, run over a few pipes, tried pumping minced eel through our spray line, and we have often come home wet and bedraggled. My wife considers that an irrigation plant offers a greater variety of excuses as to why we are late for meals, than anything else on the farm. “But it has all been worth while. We have achieved greater financial security, and certainly greater peace of mind.” Since he started irrigating, Mr Cocks has kept a full record of costs, and these are summarised as follows:Fuel including oil: 2s 6d an hour. Repairs, including replacements, new pump, charts, drain cleaning: 2s 6d an hour.

An average rate of pump-' ing 1-1/3 inches an hour this equals 3s 9d an acre inch. Overtime: 10 hours a week > at 10s an hour, when pumping lOOin a week: Is an acre inch. Truck running, shifting t plant with tractor: 6d an acre inch. Actual depreciation taking value of plant at purchase and value of plant today, £llO a year: 2s an acre inch. Total: 7s 3d an acre inch. Producing a chart showing theoretical cost, Mr Cocks gave the following figures: Fuel and repairs 3s 9d per acre inch. Total labour: 5 hours a day at 9s pumping 20 inches a day 2s 3d per acre inch. Truck running 6d an acre inch. Depreciation: £l6O, or 4s an hour, equals 3s an acre inch. Total 9s 6d an acre inch. Mr Cocks, in presenting a tentative programme for the coming year estimated his irrigation costs at £550, which would equal 21s an acre on the area capable of being irrigated, the application being 3in to 4in. Over the whole farm (which is not all covered by irrigation) the cost would be £1 5s 7d an acre. He estimated the irrigating hours at 1250 but said that 1000 would probably be more realistic. However, he did not want to under-estimate. The estimated cost gave a slightly lower operating cost than the previous figures because of the greater capa-city-acreage pumping rate of at least 1J cusecs; greater utilisation (say, 1000 hours a year thus lowering fixed costs), and less truck running. Optimum Use Mr Cocks said he thought this plant would be better applied to 300 acres, which although raising the average annual cost to nearly £2 an acre would enable the plant to effectively serve the whole farm. In other words, he said, for optimum use, one should think in terms of a cusec to 150 acres. On the financial aspect of irrigation, Mr Cocks said he thought it had raised his gross returns by £5 an acre over the whole farm and that he had obtained an average annual return of 50 per cent on capital investment This could only be an estimate, but he believed it was close to the mark. These results, and the entire design and layout depended on provision and use of a given quantity of water in relation to a given area of land, and raised Important questions concerning our present water legislation. He concluded by saying he thought that irrigation as an adjunct to a mixed farming system had tremendous I potential.