FARMER AND STOCKBREEDER.

Auckland Star, Volume LVII, Issue 103, 5 May 1926, Page 19

FARMER AND STOCKBREEDER.

(Specially Written .for tfc*— Auckland Star.")

NORTHERN PASTURES.

TOF-DRESSIXG ESSENTIAL.

(By PLOUGHSHARE.)

There is no doubt -about the value of of top-dressing to farmers of the Auckland province. There are no soils that do not respond to the application of suitable manures, and no operation that yields a more certain profit. Every year sees an increased use of manures, even on the unploughable hill-country, and there is no question about the efficacy of the practice. The benefits to.be derived are, -_efcourse, -well known, Trat may, with, advantage, be summarised. First, there is an increased yield of grass and clover, due largely to*the stimulation of the latter. Second, there is a vast improvement in the health and vigour of the herbage, and consequently in the health and vigour of the,stock grazing on it: Third, there is a marked suppression of weed-growth, and even of such invaders as bracken-fern. By far the largest proportion of the manures used are phosphatic, owing to the fact that our soils are notably deficient in this element. Even were tliis not the case, phosphates would still be all-important, by reason of the fact that they sensibly improve the feeding-value of "the herbage. Of the phosphatic manures available, superphosphate is the most largely used. This material -is. prepared from rock phosphates by treating the latter with sulphuric acid, a process that converts the insoluble, phosrhates into soluble. Saper can be used under almost 4 ,any. conditions, - and- for almost any purpose; its solubility renders it very efficient as a stimulant, •while, contrary" to the belief of .some," it is not washed out of the soil by the action of rain. It is known, how-ever.'-that in certain soils that are markedly deficient in lime, there is an clement of risk in that some of the phosphates may become converted into insoluble compounds instead of *" the reverted phosphate of lime that is used by the plants.. Some peaty soils, and certain of the volcanic soils come under this head. In such cases it is better to use lime first, or apply basic _slag. Some fanners make a practice of mixing limp and super, and this is a convenient method, but it is not always clearly understood that a cwt. of mixed lime and super is by no means as efficient as a cwt. of super. It is the super that does the work, while the lime is merely an insurance. .. ..• Basic super is a form of super consisting of phosphate that is insoluble, but is more readily available to plants than is. the insoluble phosphate found in untreated rock. It is hardly so effective as ordinary super, but -where lime is very deficient it is the . safer Of tie two, '"j

Pertinent Points. Nauru rock phosphate is not widely used owing to its insolubility. Under average conditions it is very slow in action, and despite its high analysis, is hardly such a good proposition as super or slag. Where the rainfall. i 9 high, and on moist sourish land, it may, however, be quite effective. A mixture of super and Nauru rock is often very successful. / Basic slag has for manj years been held in high esteem. By reason of its lime content; it i 3 better than super .for sour soils. Slag is particularly valuable for sweetening an old pasture and improving its feeding value. It is most effective in districts with a high rainfall, and on heavy, soils, but though its ■phosphate is. not" readily soluble, it is by no means slow acting. Bonedust is not widely used by reason of its high price, but is. one of the best manures for building up a light soil. A mixture of super and bonedust is particularly effective on the light loams such as abound throughout the Waikato. However, it is generally more profitable to invest in either :super or slag.. ■ Lime has "many advocates, and there is little doubt that nearly all the soils of this province are benefited by its application, more especially where super is largely used. . It is seldom, however, that lime in itself produces very .marked results: this is because phosphates are the most urgent need. Where finance is a consideration, it is better to put. the money ;intp phosphatic manures first; of the" two forms' the ground limestone is to be recommended; there is no particular virtue in the burnt lime a3-a manure for grass land. Potash plays an important part in the : plant-economy, and there i 3 little doubt that on the lighter classes of soil its: use is distinctly advantageous. It must be remembered, however, that phosphates are. the " first consideration, and it is only when - we have built up the supply of them that the need for potash occurs. - - . , . For old.turf.that requires sweetening, kainit 'is to be recommended j the salt in it appears v tb'have , a decidedly;beneficial "effect.' But for general purposes the 30 per cent potash salts are probably the best buying. A suitable mixture -would be 4 cwt potash, salta and 2* cwt super. Nitrogen, or ammonia (a nitrogenous compound) is not recommended -for «»eneral use. Apart,from its high cost, it is generally recognised" that the best means of securing -it is by stimulating the clovers with phosphatie dressings. The tame to apply must depend very largely on circumstances. Iα our mild climate almost any. time of "the year is effective, biit - there is little douibt that to reap the. full benefit an autumn application is the best. Where tlii3 is not possible, however, any time up to the beginning of Angust is quite suitable.

In the northern parts of. the province, nanure applied early in March will give i useful amount of autumn feed. It ie leeessary to Tise super. The growth in he following spring will not, of course, >c so great as from a late dressing.