USES OF DIFFERENT FERTILISERS
Dried Blood (7 to 14 per cent N). This has a quick and sustained action in warm soils. It is very useful for feeding plants with spreading foliage, but is probably most suitable for greenhouse plants. The best samples are fine, dusty and red powders. Dried blood is used as a rule only for top dressing growing plants at the rate of 1 to 2 oz. per sq. yd. or for feeding pot plants at the rate of about a teaspoonful for a 9-in. pot.
An almost completely soluble form can be used at the rate of l tablespoonful to 1 gal. water as a liquid feed.
Hoof and Horn Meal (7 to 13 per cent N). This is available in various grists (particle sizes). Fine grists, that is to say from ¼ in. to dust, are quick-acting, but at the same time have a lasting effect. But coarse grists (¾ in.) and hoof parings are very slow acting. Fine grists are used in growing composts for supplying nitrogen. Hoof and horn is generally worked into the ground before sowing or planting at the rate of 2 to 4 oz. per sq. yd.
Soot (l to 6 per cent N). The nitrogen in soot is present in ammoniacal form and behaves in the same way as an ammonium salt, therefore acting quickly. It also contains many trace elements. The best soot comes from household chimneys and is light and fluffy in nature. Heavy, dense soot contains ash which is of no value. Fresh soot contains plant poisons, so keep it under cover for three months before use. Scatter it over theafter digging, and then rake it in at the rate of 4 oz. per sq. yd. It can also be used for top dressing brassicas at the rate of 4 oz. per sq. yd. Never mix soot with lime.
Dried Sewage Sludge (4 to 6 per cent N). Dried sewage sludge is sold in bags by municipal authorities as a fertilizer. It is powdery, and quite inoffensive to handle. It is mainly used for supplying nitrogen and contributes a little.
Bone Manure (4 to 5 per cent N, 20 to 30 per cent P2O5). Bone meal can be obtained in coarse, medium and fine grades, the latter being fairly quick-acting. Bones crushed to 1/4 and ½ in. particles are slow in action and will supply phosphates for two years or more; fine bone meal becomes soluble as the organic acids in the soil act upon its dusty particles. The slow and steady availability of nutrients from bone meal, and the absence of harmful unwanted portions, make it a very safe fertilizer for young plants. The usual rate of application is 2 to 4 oz. per sq. yd., and it is used either by itself or with other fertilizers. The small amount of nitrogen that it does contain is as a rule quickly available.
Steamed bone flour, being a fine dusty powder, acts more quickly than bone meal, but its effect is exhausted within a year. It helps to keep fertilizer mixtures in good condition if it is added at the rate of 1 lb. Steamed bone flour to 9 lb. Fertilizer mixture.
Guano. Guano used to be the term applied to droppings of sea birds, which were collected from uninhabited islands off Peru, but it now applies to various kinds of waste products, including the droppings of bats, fish scraps and even meat residue. Fish guano is obtained from fish wastes, and is usually supplemented with inorganic fertilizers and sold as fish manures under brand names. These fish manures are quick-acting, giving a sustained supply of nitrogen and phosphorus. They are generally used at the rate of 2 to 4 oz. per sq. yd., and are best applied a few days before sowing or planting.
Poultry droppings are called poultry guano, and when dried are supplemented with inorganic fertilizers to form balanced manures that are sold under a variety of brand names. They are similar in action to fish manures and are used at the same rate before sowing or planting, or for feeding growing plants.
Most guano-based manures are normally applied in the spring, two to three weeks before sowing or planting, or as a top dressing. Excess applications do not usually cause damage, but are, of course, wasteful.
Wood Ashes. Wood ashes contain varying amounts of potash according to the materials burnt. The richest wood ashes come from bracken, the haulms ofand the prunings of trees and shrubs. They should be collected and stored as soon as they are cool enough to handle, and then kept perfectly dry, otherwise the potassium carbonate will be washed out. About 4 to 8 oz. per sq. yd. are required to give as much potash as there is in sulphate of potash applied at 1 oz. per sq. yd. Heavier dressings tend to cake the soil surface and destroy tilth. Wood ashes are inclined to make the soil alkaline, and large dressings should not be given to chalky soils.
BULKY ORGANIC MANURES
Fertilizers are not substitutes for humus-forming manures: they are supplements.
Many soils deteriorate when the humus level falls too low, and bulky organic manures have to be used. The fertility of many of the older gardens has been built up by generations of generous manuring with horse or other animal manures. But these manures are difficult to obtain easily or at a reasonable price. Farmyard manure, or F.Y.M. as it is called, is a mixture of the droppings of horses, pigs or cows, the litter used for their bedding and the urine which has been soaked up by it.
Horse or stable manure is the richest and the driest. A heap of horse manure soon starts to steam, thus showing that rapid fermentation is taking place. It is therefore called a hot manure, and is sometimes used for making hot-beds for startingor growing early salad crops. Fresh horse manure from riding stables or racing stables is often merely urine-soaked straw with a few droppings, which dwindles to a very small heap when it is stacked.
In bullock yards, as straw is added daily and is trodden in to the manure, a very much denser material is obtained. A cubic yard of bullock manure can weigh as much as 15 cwt. In contrast to a similar measure of fresh racing stable manure which may weigh less than half a ton. Cow and bullock manures are wetter and lower in nutrients than horse man-ure, and decompose more slowly in the soil, which makes them more suitable for sandy soils.
Similarly, pig manure is slow acting and long lasting. As it is slow to ferment it is a cold manure and therefore unsuitable for the making of hot-beds. When fresh it is caustic and liable to burn the roots of young plants. It is best composted with straw or garden refuse and then allowed to decompose for three months before use.