Vol. XIV. So. 



AGKIl i L NEWS 



I .• 



STUDENTS' CORNER. 



I IN \l.. 



REPRODUCTION IN FIBRE PLANTS. 



There are two important ed in 



the West 1 m li- s which produce fibre \_ trcraea 



h these belong to the rial ur i i The 



i" i i tains fiftj species, all indigenous to tropical 



America,. the latter fifteen, h lility that 



e production of fibre from A'ja >\ la, h ields sisal 



hemp, may become i i is, there 



is some reason for direi udent's attention to the 



general bi itanical nal are i i aera. The pi iling oi 



■ haracterisl ii in the drier districts oi til 



islands in the Wesl [ndies, and the student would do well 

 i iservations in connexion with this important 



matter. From a purely botani indp the inflores 



ice of these plants is inten ace biibits ; i"i h 



sexual and asexual reprod i. As a general rule after 



the berries have matured, the pi Us I md and 



the entire plant dies, the strain oi producing the enormous 

 panicle having resulted in complete exhaustion. The seeds 

 may or may not find an opportunity uinating. 



Asexual reproduction consists in the p oducti i of bulbils in 

 the axils of the bracts on the pole, [f the student removes 

 one of these structures, be will observe t hat tin-re are formed 

 at the base one 01 more tlets. In the ordinary course of 



■its these bulbils fall to the ground around the mother 

 plant, where the rootlets rapidly grow at the expense of the 



stored-up moisture and t 1 material, and then strike into the 



ground. \ characteristic feature of Furc'raea is the formation 

 of bulbils in p he flowers. This gives the 



peculiar appearance ivhich has led to the erroneous idea in 



i ■ eases, that 1 1" 1 seed is cap rminati n sitti, in 



other words, that Agave and I are viviparous. 



From an economic point of vii tv, poling is of importance 

 because it is the limiting factor in the life of the It 



is desirable that poling should be delayed as long as possible 

 in the cultivation of Agave in order that the maximum 

 number of leaves may be lined without replanting. 

 Observations have b le in Jamaica which tend to show 



that the poling of Agavi i is retarded by the presence 



of lime in the soil. Whether . observation is of quite 

 general application has not yet been fullj • d it 



would serve a useful pur] i the student made note- >n 



the poling habits of Agave .wing under different soil 



conditions. It is con eful informa aj be 



got from past observat ople (vh<5 have resided in 



different districts for long periods. At any rate it would 

 of value to endeavour to collect as much information as 



•le on a point of both scientific and ■ interast. 



Questions for Candidates. 



PR] l.l\ll\ \ V.\ . 



1. Contrast the functions of the le-aj ind the root of 



a plant. 



2. Na and describe three plants useful for hedge 



ing. Indicate t heir useful I ICS. 



[NTERMED1 vie. 



1. Give an account of the work 



experimental plots during the past yeai Station 



of the ( lolony w here yon reside. 



2. What are the different • aj s of ci soil 



moisture' 



1 . Enumi rati i n irj different kinds oi 

 can. State whii h you idei mo 



vation as a field crop 



2. I liscuss Indi in corn as a i I 



RECENT WORK ON THE PHYSICAL 



ANALYSIS OF SOILS. 



i lcI appeal s in the i \rd, 



\\.\I. No. 7, on the separation of soil pa 



, and on thi 

 soil. The information is important. Experi 

 reported to have been made on the mechanical 



above manner oi evei oil for the determinat > i A 

 humus, colloids, et :., and ii is stated that several ei 



speriments were conducted with six soils, to determine 

 the manner in which individual crops are noun 

 same soil. 



'In the first experiments, bromoform having a - i 

 weight ol 2 - 83 was diluted with benzol until at a a 



tl of 2 - 64, the heaviest part of the soils sank in the 

 mixture. By further decreasing the specific weight 

 liquid mixture to -■>:>. 2 - 49, and 2 - 36, the soils wen 

 a ted into five tractions according to specific weight, the li_ 

 of which was suspended on the liquid having a specific .. 

 of 2-36. 



•The ease or diffculty with winch a soil was sepai d 

 into its constituents was found to indicate the uniform I 



its composition. An abundant separation of the specifically 

 lighter constituents indicated a soil rich in colloids, humus, 



and available plant 1 1, while the separation ot an abum 



oi specifically heavier constituents indicate- a less productive 

 soil, poor in humus and available plant food, although not 

 necessarily with a small absolute pure food content. 



'Clay soil contained none of the constituents oi 

 v eight higher than 2'64, and the sand, loamy sand, loam, and 

 limy soil contained only I per cent., while the soils contained 

 up to 7*3. The greatest percent organic na 



colloids, and available plant food were usually found in the 



md lightest fraction, and then was usually a 

 increase from fraction 1 to fraction ."> in this respect. The 

 most silica, iron oxide, and clay were found in the fi 

 containing the most plant food. It is i included that thi 

 lysis of a soil with fluids of diffi fie weights indicates 



the relative quantities of its constituents and the distril 



of plant food in them. 



'In pot experimi nts in the plant house, crops yielded 



more dry matter per unit of area ol soil than those gro i 



lie open. The assimilation of plant food, especially 



phosphoric acid, was much greater in warm dry sill 



than ill cool summers, but the increase in drj matter was 



not correspondingly gn I Definite relal idbetween 



the quantity of plant food and the quantity of dry 



obta 1. the most marked ol which was with nitrogen. It 



is concluded that if It" 1 gramme- ol plant dry i 

 contained less than l - 61 grammes of nitrogen, - 59 

 -ram of phosphoric acid, or L'66 gran h, the 



-oil needs fertilization with the deficient foods, while if the 



100 grammes of dry matter contains m tan 



rogen, I gram of phosphoric acid, or -I I gram 

 potash, no fertilization with these plant foods is nee 



