Scientific Agriculture, 



148 



[August, 1908. 



even on a hillside, provided the contour 

 of the land is considered when striking 

 the drills. The distance apart of these 

 furrows depends on the kind of soil and 

 the fall. If the newly-sown land is of a 

 clayey nature, and very dry, the furrows 

 may be 6 to 9 feet apart, as the water 

 will spread out in a lateral direction. 

 With a steeper fall, or more porous soil, 

 the furrows must be closer together. 

 The furrows can be made by an ordinary 

 plough or a cultivation and should be 

 parallel. All dead furrows or " clean 

 outs" should be ploughed in before the 

 cross furrows are made. Having suc- 

 ceeded in bringing a supply of water to 

 the highest point in the main channel, 

 the next object is to get it into the soil. 

 To distribute it evenly to each furrow, 

 short lengths of pipe or turfs are neces- 

 sary. Sluice-boxes or pieces of board, con- 

 taining an inch auger hole, are also 

 useful. Care must be taken not to rush 

 too big a stream down to the furrows at 

 first, or the soil may " slicken," or become 

 puddled, and prevent percolation. In 

 watering maize or sorghum, water is best 

 applied down every alternate furrow to 

 germinate the seed, and then down every 

 row when the plants are growing well. 



Frequent surface cultivation is a most 

 essential operation after furrow irriga- 

 tion. The settler who, when asked why 

 he did not use more horsehoe and less 

 water, replied, " I can't sit down to 

 irrigate, but have to walk to cultivate," 

 explained a too common cause of failure 

 amongst irrigators. 



When the soil commences to crack 

 after irrigation, it is time to cultivate, 

 not irrigate. On clay soils the surface 

 may be cracked and yet the subsoil may 

 be saturated. For fruit-trees, wait until 

 the soil is almost too dry to " ball " 

 when squeezed in your hand before 

 watering again. Surface cultivation des- 

 troys the crust, fills up cracks, and by 

 preventing undue evaporation ensures 

 the necessary even degree of moisture. 

 A good rule in irrigating is never to run 

 water more than once over the same 

 surface. Give a good soaking, and when 

 dry enough for horse-work, stir the soil 

 weekly. With this treatment a 4-inch 

 watering will last two months, whilst 

 without cultivation it will only last a 

 few weeks. 



In all cases where the subsoil is not 

 porous, underground drainage i-s abso- 



lutely necessary where irrigation is 

 practised. A heavy fall of rain falling 

 after an irrigation may, in the absence 

 of drainage, do considerable harm, as 

 the soil becomes waterlogged and air- 

 tight. With crops of oats or rape the 

 leaves turn red and growth is stunted, 

 but with lucerne or fruit-trees more 

 disastrous effects follow. The roots 

 decay, encouraging the attack of " white 

 rot," or " mal-di-goma," or the plants 

 may be drowned for want of air. Under- 

 ground drains, which may be filled with 

 stones, tea-tree, logs, or any available 

 material, take up less room than surface 

 drains, and, if properly made, are more 

 effectual. In many cases where trouble 

 has occurred with alkaline salts in the 

 soil or water, it has been due to a neg- 

 lect of this important factor. With 

 underground drainage, a heavy fall of 

 rain tends to leach out the excess of 

 salts ; whereas on uudrained, flat clay 

 lands the excess moisture has to escape 

 by evaporation, and the secretion of 

 surface salts is therefore increased. 



On an irrigation area, heavy manur 

 iug, or correct rotation of crops, is neces 

 sary. If an irrigated acre of land pro 

 duces 20 tons of green-stuff every year 

 it is evident that it must become ex 

 hausted sooner than land that occasion 

 ally misses a crop owing to drought 

 Most agricultural returns are more o 

 less affected by the rainfall, but whilst 

 rain is often a remote probability, syste 

 matic irrigation is an absolute certainty. 

 Several profitable crops of strawberries 

 and cauliflowers could have been ob- 

 tained, and many a milk cheque in 

 creased, by the practice of these methods 

 during the past few months. A dressin 

 of lime, in conjunction with drainag 

 and watering, will convert many a sou 

 swamp into a luxuriant fodder patch 

 and if the feed is not required imme- 

 diately when grown, it can be easily 

 converted into ensilage. 



The application of water by the furrow 

 system followed by frequent cultivation, 

 with provision for drainage and rotation 

 of crops, are the necessary principles of 

 " wet farming," which must be practised 

 by all farmers on any large or small 

 irrigation scheme to obtain profitable 

 and permanenc results. — Agricultural 

 Gazette of New South Wales, April, 1908, 

 Vol. XIX., Part 4. 



