E. T. Chittenden

Chemical investigations on bitter pit of apples: II. The effect of supplementary mineral sprays on incidence of pitting and on chemical composition of Cox's orange fruit and leaves

Summary Coxs Orange apple trees were sprayed about mid December and mid January with aqueous solutions of the acetates of calcium, magnesium, potassium, and sodium, and of superphosphate and borax to attempt to control bitter pit in the fruit in orchards on two differing soil types. Analysis showed that use of the sprays altered the chemical composition of both fruit and leaves. Both fruit and leaves changed in composition and dry-matter content between mid January and harvest time in February or March, not only in respect of mineral and nitrogen content but also in the amounts of acids and sugars present. In one season the calcium spray highly significantly reduced the amount of bitter pit at Annesbrook orchard, but was not significantly beneficial in the second season. On the Moutere Hills orchard in this second season calcium gave the best results, although not significantly so. Potassium in the three trials was very detrimental, significantly increasing the amount of pitting. Sodium and magnesium wer...

Chemical investigations on bitter pit of apples. III. Chemical composition of affected and neighbouring healthy tissues.

Summary Discoloured tissue and neighbouring apparently healthy tissue from Coxs Orange fruits affected with bitter pit have been analysed. Discoloured tissue was higher in total ash, calcium, magnesium, potassium, sodium, phosphorus, and nitrogen than neigbouring healthy tissue. Magnesium content of the former was four times that of the latter. While healthy tissue was generally similar in mineral composition to that of whole peeled fruits at time of storage, the former was poorer in calcium. There is evidence of general migration of minerals and nitrogen from the healthy to the affected tissues. Tissue from the affected areas was very low in sucrose but was well supplied with glucose and fructose. It was richer in glucose than the neighbouring hea:lthy tissue. Reducing sugars increased markedly during storage. Apparently healthy tissue was comparable in sucrose content to that of the whole fruit at time of harvest. Starch content of affected tissue was 0.81 % and 1.17% at two orchards, while accompanyin...

Bitter pit in Cox's Orange apples

Abstract Calcium nitrate and calcium chloride tree sprays. at different concentrations are compared. Calcium chloride, with about twice the calcium content of the nitrate, gave as good control of bitter pit at half the concentration of the nitrate, which relates the effectiveness of these materials to their calcium content. Colour development on apples was better with calcium chloride than with the nitrate. The slow. movement of calcium through apple flesh is demonstrated. When inadequate calcium sprays are used,- bitter pit may develop internally without showing its: presence on the apple surface.

Serpentine and dunite as magnesium fertiliser

Abstract The uptake of magnesium by plants from the use of the magnesium silicates serpentine and dunite was compared with that from dolomite and talc-magnesite, the latter two minerals being commonly used magnesium fertilisers in Nelson. Tobacco plants, white clover, and perennial ryegrass were grown in pots filled with sawdust. Plant nutrients were supplied in solution, except magnesium, which was applied at different rates of ground fertiliser. Field trials with tobacco and pasture are also described. When the four magnesium fertilisers were compared on an equal weight basis, dunite proved to be the most efficient; serpentine was equal to dolomite in certain cases but superior in the pot trials with tobacco and clover. Talc-magnesite gave variable results. Solubility Itests with water and dilute acids showed that the magnesium silicates serpentine and dunite are readily broken down, releasing magnesium.

Influence of applications of sodium molybdate and ground limestone on a newly sown pasture

Summary On a newly sown pasture suitably treated with superphosphate four replications of applications of ground limestone at 0, 1, 5, 10, 20, and 40 cwt were set out; across these limed strips sodium molybdate at 0, 1, 2 and 4 oz per acre was applied, giving 24 treatments per replication. At low rates of liming, sodium molybdate increased clover growth more than at high rates; there was no advantage in applying more than 2 oz sodium molybdate per acre. Increasing the rate of application of limestone improved the growth of the pasture even in absence of molybdate. Three years after laying down, all plots carried the same amount of fodder in the spring. Implic3.tions of this result are discussed. Nitrogen, phosphorus, and calcium contents of white-clover leaflets varied relatively little with treatment. Manganese content was reduced by liming, but was little altered by variation in rate of application of molybdate. Manganese decreased as molybdenum content increased. A logarithmic relationship between mang...

Magnesium uptake by pastures and apple leaves from top-dressings of ground serpentine and dunite

Abstract Finely ground serpentine and dunite are compared with agricultural dolomite and talc-magnesite for magnesium uptake by pasture and, dunite omitted, by apple leaves, At the same application rates of ½ ton/ac on pasture and 1 ton/ac on apple trees serpentine proved to be equal to dolomite. Dunite raised the magnesium content of pasture to a higher level than did serpentine or dolomite.

Calcium sprays for control of bitter pit and other disorders in apples

Abstract Calcium nitrate sprays were applied to ‘Coxs Orange’ apples over four different periods between fruit set and harvest. Four sprays applied early, from 8 October to 2 December, gave no control of bitter pit. With the other three periods (II days, 27 days, and 64 days pre-harvest) there was good control of pit. The relative values of these three later spraying periods for pit control were difficult to assess, but the 64-day period gave slightly less pit in one season. The highest levels of fruit calcium were with the 27-day pre-harvest period. Over 64 days pre-harvest, 6 sprays of 0.6% calcium nitrate doubled the total calcium in apples, whereas in unsprayed apples total calcium remained practically constant. Over this period the apples gained in weight fourfold, thereby reducing the percentage of calcium in sprayed apples to one-half, and in unsprayed apples to near one-quarter. Calcium sprays reduced internal breakdown in ‘Coxs Orange’ and ‘Red Delicious’ apples. Colour development on ‘Red Deli...

Solubility of magnesium in serpentine from six localities in New Zealand

Abstract The amount of magnesium extracted in 0.01M, 0.1M, and concentrated HCI was determined on samples of serpentine from six localities in New Zealand. Responses on pastures claimed to be from the use of serpentine were found to be from molybdenum as a contaminant in the serpentine.

Sulphur responses of pastures in the Nelson district

Abstract Six soil types in the Nelson district were found to be sulphur-deficient for pastures. The amount of sulphur supplied in top-dressings of 2–3 cwt of superphosphate/ac is probably sufficient for most soils but on others additional sulphur should be beneficial.

The effect of magnesium topdressings on the growth of young apple trees

Summary Young Sturmer apple trees planted on soil low in magnesium showed severe premature defoliation and were seriously retarded in growth. Soil applications of magnesium corrected this deficiency and produced normal healthy growth.