Vol. IX. No. 206. 



THE AGRICULTURAL NEWS. 



95 



a compact mass known as a stroma. The kinds of reproduction 

 may be numerous, but can u.sually be divided into two classes. 

 In the first class are conidia of various forms, borne on the 

 ends of hyphae, often themselves arranged in some special 

 manner, but almost always fieely exposed to the air and not 

 contained in any .special receptacle. In the second class of 

 reproduction, there is one constant feature, the presence of 

 an ascus, or elongated sac, which contains generally eight, 

 sometimes four, ascospores (Fig. 11). These asci were almost 

 certainly all produced as the outcome of a sexual process in the 

 eirlier forms, but many fungi have now entirely lost this sexual 

 process. The asci are found free in the simplest forms, 

 but in the more elaborate ones they are either produced in 

 a closed box, or perithecium, or in a mass on the surface of 

 an expanded disc, which is often rolled up into a closed body 

 when young, but whii'h opens and exposes the mass of 

 asci when ripe. 



The Basidiomycetes. — This group is characterized by 

 the presence of a special cell, or l/axidiiiiu, on which the 

 reproductive bodies, or fporidia, are borne. This special cell 

 may, in the simpler forms, be divided up by cross walls, and 

 then each compartment produces one or more sporidia. In 

 the higher forms it is non-septate, and produces two, or 

 more, generally four, sporidia liorne on short stalks, which 

 project from the uppei- surface of the basidium (Fig. 1 2). The 

 basidia are generally produced on some form of fruit-body, 

 either exposed, as in the toadstools, or enclosed in a bag or 

 sac, as in the puff balls. 



The Fungi Imperfecti. — In this group are very many 

 species of fungi, which, so far as is known, can only repro- 

 duce themselves by .some form of conidial fructification. 

 Many of them have been shown in recent years to be only 

 the conidial stage of an ascomycetous fungus, and there is no 

 doubt that some form of higher fructification will be found 

 for many moie of them, as our knowledge of these plants 

 increases ; but at present, they have to be given separate 

 names for purposes of classification. 



These, then, are the four main divisions of the fungi. 

 More detailed information of the various groups will be given 

 in the sub.sequent articles. 



MANURING WITH LIME AND MAGNESIA. 

 Experiments on manuring with lime and magnesia 

 have lieen conducted in recent years at the Porto Rico 

 Agricultural Experiment Station. The following are 

 some of the results, lioth theoretical and based on the 

 experiments, as set forth in Circular No. 10 of that 

 station: — 



(1) It is always an unfavourable condition when the 

 magnesia content of a soil is essentially higher than the lime 

 content. For many plants it is also unfavourable when the 

 lime content is more than three times as high as the magnesia 

 content. 



(2) Since, by the application of farmyard manure, 

 sufticient lime and magnesia are supplied in easily available 

 form, the original lime-magnesia ratio in the soil does not 

 play such a significant part as in the case of mineral manuring 

 where potash, phosphates and nitrogen are added. 



(3) Most kinds of cereals develop best when the lime 

 content is equal to the magnesia, content, or does not exceed 

 this proportion. 



(4) Leguminous plants, and probably many others, 

 require relatively more lime than do cereils, the lime-magne.sia 

 ratio being here more favourable. 



(5) Plants, like tobacco and the grape, which can exclude 

 an excess of absorbed lime from further physiological influence 

 by precipitation as calcium oxalate in the cells of the leaves 

 and stem, can also show a very favourable development in 

 such cases where the lime content of the soil exceeds the 

 magnesia content by more than three-fold. However, there 

 is a limit in this respect, since the regulative powers of the 

 plants are imperfect. 



(6) An application of pure limestone on poor sandy soils 

 has often caused a decreased harvest, to the surprise of 

 the owner. It may be safely assumed that in such cases, 

 the magnesia content of the soil was far below the lime 

 content, and that an increase of lime ren<lered, therefore, the 

 ratio of lime to magnesia still more unfavourable than it was. 



(7) From a practical point of view, the ratio of 2 parts 

 of lime to 1 part of magnesia in the soil would be the most 

 desirable, since this approaches on the one side the best 



•ratio of lime to magnesia, for cereals, and on the other, the 

 best for the leguminous plants. 



(8) The lime-magnesia ratios mentioned thus far, hold 

 good for the condition where both bases are present in the 

 .same state of availability. If, however, the one should be 

 present in a water-soluble form, and the other in a form not 

 soluble in water, then the ratio entering the root would of 

 course difier from the ratio present in the soil, the former 

 being capable of rapid absorption by the plant, the other not. 

 This pofnt is especially important when manurinc is 

 considered. 



(9) Some care has to be exercised in manuring with 

 magnesium sulphate. Clayey and loamy soils can be treated 

 at first with 200 to 500 kilos, per hectare (176 to 440 lb. 

 per acre), eventually with more; but on sandy soils such large 

 doses would not be advisable, partly because the sulphate may 

 be lost again by leaching. Smaller doses, applied annually, 

 are preferable. The most ettective form of application is 

 a top dressing with dilute solutions. 



(10) In cases of an excess of magnesia over lime in 

 a soil, it will be of great advantage to apply the nitrogen in 

 the form of calcium nitrate, or as the so-called lime nitrogen 

 (calcium cyanamide), since in this way a special manuring 

 with lime may be avoided. When calcium nitrate or lime 

 nitrogen is applied on soils too rich in lime, then magnesium 

 sulphate.fihould be applied in conjunction with it. 



(11) 'WTien heavy clay or loam soils have to be loosened 

 by liming, the ratio of lime to magnesia in the soil should be 

 considered. Accordingl}', pure limestone should be applied 

 when the magnesia content in the soil is higher than that of 

 the lime, while magnesian limestone should be used if the 

 reverse is the case. Thus at the same time, the soil is loosen- 

 ed and the ratio of lime to magnesia improved. 



(12) It is also necessary to consider the ratio of lime to 

 magnesia when correcting the acid or alkaline reaction. 

 Soils of alkaline reaction should receive gypsum for neutraliza- 

 tion, if the magnesia content is higher than that of the lime, 

 and magnesium sulphate when the magnesia content is too 

 far below that of the lime. 



(13) It may happen that loosening a heavy clay soil, or 

 neutralizing the acidity of a soil will have a much more 

 powerful influence on the productiveness than the correction 

 of the ratio of lime to magnesia, but this is no reason why an 

 additional advantage should not be secured when those evils 

 are remedied. _ .. . . 



