896 



THE TROPICAL AGRICULTURIST, 



[May - 1, 1883. 



3; Clay. , . 



i? Soil mixed up by manure, compounded by organic mat- 

 ters. AocoriliDg to this distribution for experiments have 

 been taken. 



(1.) Sand soi], containing 100 per cent sand. 

 ' (2.) Calcareous earth, containing coarse gravel 1'6 percent 

 Limestone in dust form 96'0. 



Clay 



3. Fuller's earth containing coarse gravel 



Olay 



Horse-dung. 



Garden-soil, containing sand ... 



Limestone in dust form 



Clay 



Manure-earth and manure 53. 

 From each substance the same volume has been taken : 

 400 U.iJ.M. substance free of water weighed : 

 Sand ... 600 g. 



Oalcareous earth 400 g. 



4. 



2-3. 

 4-0. 

 95-6. 



61 per cent. 



12-6. 



20-0. 



£a 



■ d'ffl 



1 l.-8atUfo!i|lKi»pacitv' for rainwater pretty pretty very 



, ^rrp *. p _r~ Weak Weak stfoiig strout^ strODg 



'I''- '■ -i' volume 1 0-39 0-30 0-44 



!..■:! [.-OHf. M.'r ! :: - weight 1 0-57 0-20 0-42 

 2. •H-njyina'iitet.'ljeSjig saturated with pretty 



f water ■ ... ... ...quick quick slow 



QuickneiM of evaporation 

 " ' mm per day ...4'30 3'70 



iDuriog tlie; drying 



0-48 

 0-84 



0-54 

 103 



5I0W quick 



3-50 

 5- 



4-30 

 7- 



4-50 

 3- 



3." 



PfjrmeatiMKabUitv shown after the very pretty very 



evaporation in the moniiug;. ...strong weak weak weak strong 

 PrOporlioiial number of days, on 



.1- which the evaporation over- „. „ „, 



I Ijalanped pn the morning ... U-69 0-24 014 0-29 OSl 

 Density o£ the mechanical resist-') 



ance Tnadeagainstevaporation, (prettystrougmod- mod- weak 



by Which re.sutauce the drying ji 

 up is delayed. J 



strong 



erate erate 



Relative quantities of 

 .water 

 5:— Hygroscopicity 



8. 



retained 



... 0-89 117 0-7ii 0-81 0-66 

 ...pretty very weak pretty very 

 weak weak strong strong 



In 100 g. substance g. water ... 5-60 210 3-60 700 41-00 

 6.— Condensing power (effect of the ) pretty-pretty very strong very 

 hygoscopicityj for the water- ("gtrougstrong weak strong 



vapours of the atmosphere j o □ 



Comparative height of the water 

 vapour condensed every night 



by the dry substances mm. 0-13 0-13 0-05 0-19 030 



7. — -VVarmiag by influence of thesuu- 



rays ... ., • .„ ... ... very warm pretty warm very 



warm warm warm 



Comparative overplus of temp- 

 eratnrt^ of the very substances ~ 

 over 1 In' trmperature of the sur- 

 rounding alninsphere ...14-20 ° 1070 => Q-OD =■11-50 = 18-7° 

 Nightly couliug. Lowering of the 

 temperature below that of the sur- 

 : rounding atmosphere ,.. ... l-60° 170= 1-80° r80°0-80° 



9.— Given air by atmosphere ... strong very prettystroiig very 



Weight of oxygen, which can b iveak strong strong 



absorbed bv 100 g. substance ... 14-18 1-60 1010 15-30 2030 

 The experim.-nts continued from 2Uth May till 20th September with- 

 out any iuterruptiou. Their results are written down in this table, 

 which is completely copied. The given numbers characterize the 

 qualities of the soil-elements, whicn have influence on the evapor- 

 ation of the ^vateI-; they show the satiating coefficient, relative to 

 weight arid volumes; they show the different fiuickness of evapora- 

 tion and the space of time up to the normal drying; furUier they 

 prove the natural influence of the porosity of the surface, the mechan- 

 ical influence of substance, and the influence of the hygrosiopicity 

 as well by the ability of retaining water as by condensing water 

 vapoin- from the atmosphere; finally they state the degree of warm- 

 ing by the sun rays and that of cooling by nighttime. By the examin- 

 ations, the following general conclusions follow for the practice: — 

 ,,>'A, .-, 1, — Cultivation of the .Sartrfsoi/^.. ,-'.\ '.-.., , 



Sand is saturated by a proportional Bmall quantity of 

 water, and dries out very quick. But the little porousness of 

 it and the cons,iderabIe compactness allow to conserve a 

 small stock of water in the lower parts of it, and being liy- 

 groscopic enough for condensing atmospheric vapour of 

 ■water on its surface. However, the upper parts ofthesund 

 grows hot very much by the influence of the sun and it ab- 

 sorbs only a little of ozygen from the air. Consequentl 



the sand-soils are not much favoui-able for the vegetation. 

 They can be cultivated profitably only by ample supply of 

 manure, by what means they get able to retain rain-water in 

 sufficient large' quantities. For growing grass irrigating is 

 neces.sary. It is very profitable to roll sand-soil, being always 

 dry and warm, to raise the resistance against becoming dry. 



2. — Cultivation of the Calcareous Earth. 

 Those soils, coutaining lime in dust form in such quantity 

 as to make it predominant, are very scarce ; here are only cal- 

 careous and marly grouuds to name: — 



The calcareous soils consist of coarse gravel and Hmestone 

 in dust form in smaljer or larger quantities. "We see that 

 this calcareous soil is able to retain more water than satid 

 soil, becoming dry less quick, the compactness of it being 

 smaller, the hygroscopic qualities only a little more con- 

 .siderable; finally growing less hot by the sun aud airing 

 itself better. The calcareous soils ought to be cultivated 

 like sand .soils, but they will be generally more productive, 

 making better use of the manure thau sand. 



The marl-soils are dense mixtures of clay and liiBe-stone 

 iu dust-form ; the qualities of the clay are always predomin- 

 ant in slur soils, they m,ust be treated iu the same manner 

 as the clay-soils, but the limestone will improve the ex- 

 cessive qualities of the clay, thus contributing to the fert- 

 ility of the soil. By all means the presence of a consider- 

 able quantity of limestone is an element of fertility for all 

 soils, sandy as well as clayey, not only by the named rea- 

 sons, but also by helping to effect the decomposition of the 

 manm'e. From that reason soils, being iu want of limestone 

 are supplied with limestone and olay artificially with great 

 success. 



3. — Cultivation of Clay Soils. 



The name clay soils is given to soils, in which the spe- 

 cial qualities of the clay are predominant. It is sufficient 

 for that purpose, if there are about 30 per cent of clay. 

 Clay is able to keep large quantities of water, without 

 being too wet. it becomes dry only by slow degrees. The 

 hygroscopic qualities of it prevent very much its becom- 

 ing dry and enables it to condense large quantities of 

 water-vapour from the atmo,sphere. It gets hot in the sun 

 as much as sand, accelerating by serat, the decomposition 

 of the manure. The clay is an element absorbing very much 

 oxygen and therefore very favourable for vegetation. But 

 the clay has also its faults, which can be removed by good 

 cultivation. The clay soils are very damp and ought to be 

 well drained, and by deep renovated ploughing. It can 

 receive a great deal of manure, which being able to effect 

 a poriness favourable for penetrating of the sun-heat and 

 circulation of the air. 



4. — Analyses of the StaUe-Duny. 



(1.) Besides the manuring effect of the stable-dung, it is 

 able to retain the largest quantity of raining-water (110 of 

 100 weigh; 56 for 100 of its volume.) 



(2.) An account of its great porousness it acquits itself 

 very quick of superfluity of water ; three days of fine weather 

 are sufficient, to make it loose all excessive water. 



(3.) Its great hygroscopic qualities allow it to conserve 

 for a long time as much water as sufficient for the veget- 

 ation. 



(4.) To the hygroscopic qualities of the stable-dtmg it is 

 owing, that it retains even in air-dry condition 40 parts of 

 water for 100 parts of its own weight, that water remains 

 for supplying the plants, that is to say, the soil provided 

 sufficiently with stable-dung, contains ueither too much, 

 nor too little of the rain water. 



(5.) The stable-dung, kept in the upper parts of the 

 soil, condenses very much water-vapour from the sur- 

 rounding air to end of the night ; it receives by this dew 

 carbonic acid, ammoniac salts, nitrates and other things 

 important for the vegetation. 



(6.) Also thestable-lung mostly contributes to making 

 the soil able to absorb the sun-rays which bring life into 

 tho.se il. 



(7. ) Finally, the stable-dung absorbs more than any other 

 soil, the oxygen of the .air, which is the strongest means tor 

 decomposing manure and the best agency for almost the 

 whole subterranean course of Hfe of the plants. 



(8.) It is to be added, that abuudant stable manure be.s- 

 tows upon the soil the ability to remain moist aud full of 

 poriness. 



A soil deficient of stable-dung loses by drying up very 



