Successful Trials With Reverted Phosphate

Poverty Bay Herald, Volume LXIII, Issue 18918, 21 January 1936, Page 10

Successful Trials With Reverted Phosphate

DY mixing super :unl carbonate oi lime 1 ogcther :t lew .farmers some N'eiiis ago discovered that matked i(* sell;; couM In' obtained from this practice, particularly vvlien t ln- mixlitre was sown with rape or kale, anil when sow inn down grass.

Taking the mat tor up, the Department id Agriculture carried out n 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 protitable quantities to use pur acre with rape and kale crops. As result of lire trials several important conclusions were readied. .It was found that the addition of lime to the super improved the germination very materially and that the yield pei acre was increased. The highest yields were obtained by sowing down every coulter; these crops required heavier fertilising than the usual 1 ewt. or one bag pur acre. The pro senee 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, how ever, but must be used in addition to the super.

Super gives its correct response on soils of high lime content. When super is applied il reverts to the citrate soluble form, and, owing to the lineness of its particles, is quickly distributed in the soil, where it readily becomes available as plant food.' If lime is deficient, the neces J

sary reversion of the super in the soil will be effected. The addition of lime to the super brings about the accessary 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 ares mixed'. Sometimes the mixing takes place in the drill. While these methods are giving fairly satisfactory results, the correct way is to mix aid allow the mixture to stand several’ lays before sowing, and to turn it several times while on the floor. Undoubtedly this involves additional work, and lo use the proper heavier quantity required by these crops witlii the lime added is more diflicult still, but it is well -worth-while. The introduction of reverted phosphate, which is super 44-40 with a small and carefully calculated quantity of burnt lime added, has en iibled 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 fanners mix their own super and carbonate of lime.

By this means the sowing of heavier quantities of fertiliser which turnips, rttj'le and kale require, is made easier, there being no mixing and on more handling of the super be fore the lime is added. The heavier quantity of reverted phosphate can be used with perfect safety to germination. In the ease of turnips, rape, and kale, the quantity recommended for use is two bags of reverted phosphate to the acre. On heavier soils or

in districts bf'higher rainfall heavier quantities can well he applied. A fact which should be borne in mind when sowing grass with these .wops is that there are two crops to be fertilised. The turnips, rape or

kale are drilled in and the grass :i; usually broadcast. II is necessary therefore, to broadcast reverted phos-

phate for the grass as well as to drill P in fur the root crop. This may be done when the final cultivation takes place before drilling.

The use of lime is benolieial 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 mu! worked into the ground during cultivation.