REVERTED PHOSPHATE

Waipa Post, Volume 52, Issue 3705, 10 January 1936, Page 7

REVERTED PHOSPHATE

SPLENDID FERTILISER FOR CROPS. SUCCESS OF TRIALS. By mixing super and carbonate of lime together a few farmers some years ago discovered that marked„results could be obtained from this practice, particularly when the mixture was sown with rape or kale, and when sowing down grass. Taking the matter up, the Department of Agriculture carried out a number of trials in order to discover the reason for the better results, the correct quantities of super and carbonate of lime to mix together, and the most profitable quantities to use per acre with rape and kale crops. As a result of the trials (writes “Cultivator” in the Dominion) several important conclusions were reached. It was found that the addition of lime to the super improved the germination very materially, and that the yield per acre was increased. The highest yields were obtained by sowing down every coulter, as these crops required heavier fertilising than the usual 1 cwt or one bag per acre. The presence of the lime enabled farmers to sow increased quantities of super, to secure higher yields, and still obtain perfect germination. The lime cannot be regarded as a manure, however, but must be used in addition to the super. Super gives its correct response on soils of high lime content. When

soluble is applied it reverts to the citrate soluble form, and, owing to the fineness of its particles, is quickly distributed in the soil, where it readily becomes available as plant food. If lime is deficient the necessary reversion of the super in the soil will be affected. The addition of lime to the super brings about the necessary reversion before the super is applied to the soil. It is still in a highly soluble form and is in the correct form in which it is used by crops, that is, the citrate soluble form. Many farmers mix their own super and lime in varying quantities, and usually sow immediately they are mixed. Sometimes the mixing takes place in the drill. While these methods are giving fairly satisfactory results, the correct way is to mix and allow the mixture to stand several days before sowing, and to turn it several times while on the floor. Undoubtedly this involves additional work, and to use the proper heavier, quantity required by these crops.with the lime added is more difficult still, but it is well worth-while.

The introduction of reverted phosphate, which is Super 44-46 with a small and carefully calculated quantity of burnt lime added, has enabled farmers to overcome these difficulties. The trouble saved in mixing and handling more than pays for the small reduction in analysis. The mixture is fully matured and the proper reversion of the super takes place. Reverted phosphate is also in the proper free drilling condition when delivered, which is not always the case when farmers mix their own super and carbonate of lime.

By this means the sowing of heavier quantities of fertiliser which turnips, rape and kale require, is made easier, there being no mixing and no more handling of the super before the lime is added. The heavier quantity of reverted phosphate can be used with perfect safety to germination. In the case of turinps, rape and kale, the quantity recommended for use is two bags of reverted phosphate to the acre. On heavier soils or in districts of higher rainfall heavier quantities can well be applied.

A fact which should be borne in mind when sowing grass with these crops is that there are two crops to be fertilised. The turnips, rape or kale are drilled in and the grass is usually broadcast. It is necessary, therefore, to broadcast reverted phosphate for the grass as well as to drill it in for the root crop. This may be done when the final cultivation takes place before drilling. The use of lime is beneficial to these crops provided it is applied in worth-while quantities of half a ton on the light to medium soils, and one ton on the heavier soils, broadcast and worked into the ground during cultivation.