The Philippine Agricultural Review Part 4

B. A. No. 741 (Palawan), 1749 (Mindoro), 2182 (Benguet).

Citrus excelsa. Limon Real.

A th.o.r.n.y, tall shrub of vigorous growth, straggly habit and interlocking branches, with stout, long, sharp thorns; young growth purplish; leaves 9.5 to 16 centimeters long, 4.5 to 7 centimeters wide, elliptical oblong to ovate oblong, crenate to serrate, thick and leathery; base rounded; apex retuse; petiole 19 to 37 millimeters long, quite broadly winged, in large leaves the wings frequently exceeding 2 centimeters in width; flowers 3 to 7, in axillary, rather loose cymes, 36 millimeters in diameter; calyx medium large, cupulate; petals showing trace of purple on the outside; stamens 34 to 35, unequal; filaments occasionally free, usually united into groups of 2 to 6; ovary roundish, 10 to 14 loculed, 4.5 millimeters across; style distinct, 5 millimeters long; stigma large; fruit 5 to 7.3 centimeters long, 5.5 to 7.5 centimeters in equatorial diameter, weight 115 to 225 grams; form subglobose; base rounded; apex flattened; surface smooth, greenish to clear lemon yellow; skin thin; pulp greenish to grayish, in good varieties very juicy, mildly acid, and of excellent flavor; juice cells long, slender and pointed.

Plant material of the limon real has been collected in Tarlac, Bontoc, and Bohol, and the fruit is at rare intervals offered for sale in small quant.i.ties in Manila.

The name of the plant, "Royal lemon," indicates the esteem in which the fruit is held by the people, and while it is unfortunately true that most fruits tested have been too dry to be of any value, yet in the best types the fruits in quality and aroma surpa.s.s all lemons and limes that the writer has had the opportunity to sample. With its robust, th.o.r.n.y growth, large leaves and broad-winged petioles and considering its affinity to the lime and lemon together with the roundish oblate fruit with 34 to 35 stamens as against the 20 to 26 in those species and with its 10 to 14 locules, this plant is apparently as distinct from the lemon and lime as these species are from each other.

B. A. No. 1727 (Bontoc?).

Citrus excelsa var. davaoensis.

A th.o.r.n.y, arborescent shrub of straggly habit, with interlocking, drooping branches, and of vigorous growth; young growth green with tinge of purple; leaves 8.5 to 13.5 centimeters long, 3.8 to 5 centimeters wide, ovate to oblong ovate, crenulate to serrulate; base rounded; apex sometimes retuse; petiole 16 to 30 millimeters long, with wings ordinarily narrow, in large leaves sometimes 15 millimeters wide; flowers not seen; fruit 6.4 centimeters long, 8 centimeters in equatorial diameter, weighing 317 grams, oblate; base rounded; apex flattened to depressed, wrinkled, with a circular depression around the raised stigmatic area; surface otherwise fairly smooth, lemon yellow; skin thin, central cavity large; pulp contained in about 13 locules, light colored, quite juicy, sharply acid, and of good flavor; juice cells long and slender.

Ripe fruit of this species has been received from Davao, Mindanao, in December and January. The fruit is perhaps too large for retail trade, but might possibly be utilized in the manufacture of lime juice and allied products.

Full-grown plants of C. excelsa or the variety above described have not been seen, but C. e. davaoensis appears to be smaller than C. excelsa in all respects, the fruits excepted. There has been no opportunity for an examination of the flowers but so far as observed the plant appears more closely related to C. excelsa than any other species herein described.

B. A. No. 1009 (Davao, Mindanao).

Economic Value of the New or Little Known Species.

The horticulturist and plantbreeder, ever on the alert for new plant material that may enhance his profits, extend the cultivable area of his crop, or be used in making new cross combinations, will naturally ask himself of what value are these new plants and fruits. Briefly stated, it may be said that the "Tizon" is a dessert or breakfast fruit of high, if not perhaps the highest, order, its main defect being the unsightly basal projection. Then, as stated elsewhere, the best "limon real" is unsurpa.s.sed in quality for "ade" making. Perhaps third in importance are the better types of the alsem for the manufacture of citric acid, etc., and it might find a sale in compet.i.tion with the lemon and lime, depending to a great extent upon its keeping qualities. The juicy, thin-skinned, and few-seeded talamisan may find lovers as a breakfast fruit and is also of the right size for an ade fruit. If cultivation would increase the juiciness of the panuban, this fruit may find favor with many. A good marmalade may be made of the calamondin. The above species or varieties have more or less of a future on account of their pomological merits, and the plant breeder, by crossing them and the cabuyao and canci with old cultivated species, might obtain valuable results.

There is also the prospective value of the new species as stocks. To determine the congeniality of these species and the old cultivated citrus fruits and their value as stocks under various soil conditions would of course require the labor and close observations of many years.

The calamondin is quite drought resistant and would probably dwarf the scion. One year old buds of the pomelo, lime, mandarin and orange at Lamao have made satisfactory growth, the buds taking without difficulty. The cabuyao is a very vigorous tree and is also drought resistant. It has recently been budded with the cultivated citrus fruits, the buds "taking" very well. The orange has been budded on the alsem, resulting in a good growth, being now (December, 1914) nine months old. During the trip to Bohol in May, the limao, growing in a coraline lime-stone formation overlaid with a little humus, the exact counterpart of the Bahama Islands or the "hammock lands"

in southeast Florida, impressed the writer as one of the best examples of drought resistance among citrus fruits under such conditions. The talamisan also appeared quite drought resistant, and is furthermore of value as a live fence because of its large spines.

The "limon real" is of great vigor and hence may be a desirable stock for certain varieties and under certain conditions.

BY-PRODUCTS OF SUGAR MANUFACTURE.

By Cleve. W. Hines, M. S., Station Superintendent.

In various lines of manufacturing there are certain by-products which, years ago, const.i.tuted a waste and great loss, but which now under modern methods have become in many cases of considerable importance.

This is especially true with the sugar industry. Extreme care and attention is required to keep the balance on the right side of the ledger, and often the proper handling of the by-products forms the deciding factor between success and failure. In order to build up a great sugar industry in these Islands, more attention must be given to the details of the work, and many of the present losses must be turned into profits before great progress can be expected.

Cane Tops and Trash.

First in the series of by-products in the manufacture of sugar, comes cane tops. The amount of this material produced per hectare will depend upon various factors, including the variety of cane, its stage of maturity, etc. The less of these tops, of course, that may be produced for a given amount of cane, the better it will be for the growers, nevertheless they have a good feeding value if properly handled.

Professor Dodson, [3] director of the Louisiana Experiment Station, states that he found cane tops to have the following composition:

Per cent.

Protein 1.53 Fat 0.41 Carbohydrate 15.62 Fiber 8.87 Water 71.50 Ash 2.07

The fiber content would be slightly higher and the water content lower, for tropical cane, since maturity is completely reached before harvest begins. It may be seen from the above a.n.a.lyses that this makes a most excellent feed for work animals. Certainly greater advantage should be taken of this feeding stuff than is usually done, since there is a scarcity of pasturage near the end of the harvest season and the animals become needlessly thin on account of lack of feed. At present very little of this material is utilized, but instead is burned on the field with the rest of the trash. If the tops are removed and used as a stock feed, only the leaves and pieces of stalk remain, and these make a good fertilizer for cane lands.

It is the general custom in these Islands to burn all of this material as soon as the crop is harvested. The object of this burning is to destroy any insects that may be present, as well as to facilitate subsequent cultivation. In the writer's opinion neither of these reasons is sufficiently well based, since in this country large numbers of troublesome cane insects are not found. If they were present in sufficient quant.i.ties, the trouble could be handled by placing the trash between the rows and properly treating it before plowing it under. This should be the method of disposing of the trash at all times. In this manner the waste material could be utilized, and the organic matter would be even more valuable than that contained in many of the commercial fertilizers. The nitrogen contained, which amounts to from 0.5 to 2 per cent, would be practically all saved, while with the burning method this is completely lost.

In Louisiana, cotton-seed meal forms one of the princ.i.p.al nitrogenous fertilizers for cane lands. This material costs from P50 to P75 per ton and Dr. Stubbs, [4] in his research, found that the trash burned from each ton of cane caused a loss of nitrogen equal to that contained in 27 pounds of cotton-seed meal. Besides this loss of nitrogen encountered in the burning of the trash, the organic matter which would later form humus is completely destroyed. Soils would retain moisture better during the dry season and be more easily handled if the conservation of organic matter were given greater attention. There is also a great injury done to the remaining stumps and top roots by this burning which is very detrimental when the field is to be used for a ratoon crop. Where cane is badly infested with destructive insects, it is quite another thing. This again brings up the fact that the cane points should be treated with chemicals before planting, in order to complete the work of destroying these insects.

Use of Ashes.

The ash of sugar cane const.i.tutes the mineral matter that has been taken out of the soil. This usually runs about 0.48 per cent of the total weight, according to Payson's cla.s.sical a.n.a.lyses. Chemically this contains the following: silica, iron, aluminum, lime, magnesia, potash, sodium, phosphorus, sulphur, chlorine, oxygen, water, etc. Of these various elements, the phosphorus and potash are the most valuable to the planter. Lime is also useful for many soils in correcting the acidity, and occasionally in supplying that element, when it happens to be lacking in a particular soil.

The cost of different fertilizers is governed by the percentage of these plant-food elements contained. Phosphoric acid is worth $0.05 per pound (P0.22 per kilo) in crude fertilizers. At this rate the value of this element recovered from a crop of 75 tons of cane per hectare would be from P10 to P12.

Potash is valued at about P0.26 per kilo and that removed with a crop of 75 tons would cost about P25. The lime contained is a cheaper element but will not act as a detriment on any soil, while on many it will be found very helpful.

In spite of the great deficiency in these elements in the cane lands here, and the high cost of commercial fertilizers, this waste material is not only neglected at the majority of the factories but is actually thrown away, yet the same elements that command a high price in commercial fertilizers are contained in these ashes.

Filter-press Refuse.

In the defecation of cane juice, certain chemicals are often used to precipitate the impurities, which are removed from the subsiders after the clear juice has been drawn off, and sent to the filter presses, where it is filtered through heavy cloths. This material contains coa.r.s.e particles of baga.s.se together with other impurities including the lime and phosphoric acid which were used in this work. The composition of the material depends upon the original composition of the juice and the amount of the different chemicals that has been used in the clarification. In any event, it makes a most valuable fertilizer because of the organic matter, nitrogenous bodies, phosphoric acid, and lime that it contains. This organic material is an ideal substance to be applied to the worn-out cane lands (which consist almost entirely of mineral substances) since it induces bacterial action, and during its decomposition certain acids are freed, such as carbonic, nitric, and organic acids. These have the power to act upon the mineral const.i.tuents and thus liberate other plant-food elements. The filter-press mud can very well be mixed with the baga.s.se ashes, and scattered about the cane rows as an almost complete fertilizer for sugar cane, the only element lacking being nitrogen, which was lost in the burning of the baga.s.se.

It will be remembered that in the synthesis of sucrose, which consists of carbon, hydrogen, and oxygen, there are none of the plant-food elements used which are sought for in commercial fertilizers. These are used only in building the fibrous stalk of the cane and they may all be recovered in the baga.s.se and cane-juice impurities. The carbon, hydrogen, and oxygen which are used practically all come from the air and water.

It is a custom to-day to cart this ash to piles or depressions some distance from the factory. In some places it is thrown into the river, or cast into the sea--an absolute loss.

Planters must not depend upon commercial fertilizers for their supply of plant-food material, when there is such an abundance of natural fertilizer being wasted. The cost of the artificial fertilizers in many cases is considered prohibitive and often unnecessary. In order to build up a great sugar industry here, the material at hand must be used, while money should be spent for modern apparatus and equipment.

Mola.s.ses.