Unproductive Yams

Press, Volume CIII, Issue 30395, 20 March 1964, Page 6

Unproductive Yams

Can you tell ma: (1) What is attacking my gooseberry bush? (2) The reason my yam plants have failed to produce tubers although the top growth is excellent? (3) What can bo done about soil such as the enclosed, in a new part of my vegetable garden that I have recently cleared?—lnes (Christchurch). The failure of yams to produce tubers frequently occurs where there has been excessive plant food available, thereby stimulating lush topgrowth at the expense of yam-production. It is not restricted to yams but can occur in potatoes and other root crops. There is the possibility that under suitable growing conditions some yams may still be produced; however, they would be much smaller in size. It is not possible to conduct an analysis of so small a soli sample or to make very helpful suggestions from it,. However the incorporation of well-rotted compost and possibly lime would greatly faciitate working it and improve its fibrous content. It has been found impossible to Identify the symptoms showing-on the gooseberry leaves, so unfortunately no remedy can be given. I was interested in your article in "The press” regarding the use of sawdust and blood and bone. I have a dozen roses on order for planting later in a bed with a northerly aspect, against the house, and am wondering if blood and bone and sawdust would suffice to enrich the soil In place of stable manure. Alternatively, I have nitro-phoska (yellow) on hand which may be more suitable (with sawdust). The soil is on the light side. May I have your advice as to what is best, please? H.M. (Christchurch).

The answer to your queation is somewhat dependent on the quality of either of the materials you are considering to apply. Personal preference is for wellrotted stable manure, which should bo liberally applied to the soil and well forked in considerably in advance of planting. Sawdust can be added as a mulch during the warmer months of the year, while an annual spring-time application of blood and bono wilt prove most beneficial. Yellow nitrophoska contains loss potash, an essential element for good roao culture, than the red or bluo products, and primarily intended for magnesium deficient soils. I enclose a specimen of Ngutukaka for your comment. Is the bushy side growth the result of some disease and, if so, what means should be adopted to . combat it? This particular bush is situated in a south* orly aspect with practically no protection from gales. Two other kaka shrubs which are sheltered from souther* lies are quite free from this growth. Also can you comment on the fact that an excessive crop of Bon Chretien pears is taking place on one of my trees, which is heavily laden, in spite of the definite lack of suggestion that wind is the cause. The tree itself is in a hjalthy condition.— “Kaka Beak'* (Templeton). The distorted growth on your kaka beak (Clianthus puniceus) is commonly known as T *Witehes* broom” and is caused by a small mite, Aeeria cliantht.

Control can begin now by cutting out the bushy sections to reduce the mite population and then applying lime sulphur 1:15 Earts water, just before bud urst in spring. It is not easy to give a definite answer concerning the pear tree but 1 would suggest that it is associated with excessive dryness. Regarding your recent article on the uses of sawdust wherein it was stated “that rotted sawdust has most of the advantages of peat." As I have been unable to buy any peat and have read that it is very good for growing gerberas 1, could sawdust be used as an alternative, and if so, neat or mixed with soil? The soil I have is on the light side. What artificials should be used?—V.B. (St. Albans).

Rotted sawdust can be used instead of peat and should be incorporated into the soil in a similar manner as you would any other organic matter. Nitrogen is not so important for Serberas and fertiliser mix in be ratio 1:1 at 4oz to the square yard will prove beneficial. Alternatively, if insufficient organic matter is available, blood and bone could be substituted for sulphate of ammonia but increasing its proportion by three to four parts to two of phosphate and one part of potash.