1596 MANURES AND MANURING 



cover the surface with crops which are of great and immediate value to 

 the population. 



Where the conformation of the land will allow it, surface vegetation 

 will gradually appear if the soil is left quite undisturbed. Elymus arena- 

 rius and Agriopiiyllum arenarium are the first to establish themselves 

 and their roots rapidly spread over the surface and down into the 

 sand to a depth of even 5 or 6 yeards. Later other species appear, grad- 

 ually covering the surface and protecting the sand from the action of the 

 wind. Then finally the two first comers disappear and their places are 

 taken by Artemisia maritinui which provides excellent sheep pasture. 

 But to complete this process, 20 or 30 years are required and it is generally 

 more satisfactory to hasten matters by artificial methods, at least on some 

 parts of the area, so that centres for seed distribution may be formed 

 and help in the natural reclamation of the land. Usually the procedure 

 is as follows : a survey is made of the area, to pick out places which are 

 sheltered from the wind, such as the hollows of the dunes. Seed of Ely- 

 mus arenarius and Agriophyllum arenarium is then sown in patches of 

 about one square yard on these selected spots and at the rate of 3 to 6 

 lbs. of each per acre. The crests and flanks of the dunes, where seed- 

 lings would at once be destroyed, are not touched. 



All seeds are supplied from Government seed stations of which 10 

 are already established and occupy 35 acres of land. Cuttings and young 

 woody plants are also raised in Government nurseries. Those in the 

 north of the province grow pines, birches, oaks, black poplar, etc., while 

 those in the south produce robinia, apricots, Pterococcus apJiyUus and 

 Calligunum spp., the total area under nurseries being 150 acres. 



Replanting is only just in its initial stages. In 9 j^ears not more than 

 45 acres have been planted besides 3 gardens and 4. vineyards occupy- 

 ing about II acres. The real obstacle to progress in this direction is the 

 uncertainty as to whether the greater part of the province of Astrakan is 

 adapted to the establishment of forests ; but with the institution, of 

 the special State Service referred to above, the question will receive proper 

 attention and in the event of a favourable report, planting will proceed 

 more vigorously. 



MANURES ' 1 165 - Research on Superphosphates. — Pratolongo U., (Agricvdtural High School, Milan) 



AND MANURING in Awial' iL Chimica upplicata, Vol. VI, Nos. 3 and 4, pp. 59-112. Rome, 1916. 



The mechanical condition of superphosphates is a most important 

 factor in estimating their value, as unless the manure be dry and in a 

 very fine state of division it is impossible to spread it evenly on the land. In 

 order to determine how the friability and dryness are affected by the con- 

 ditions of its manufacture investigations were made on the constitution 

 of the substance in the various .stages of the process. The results are 

 summarised as follows : 



i) Superphosphate contains three chief constituents, calcium sul- 

 phate, mono-and dicalcium phosphate, which are found in a more or less 

 hydrated condition and under various crysralHne forms. Calcium sul- 



