370 



THE AGRICULTURAL NEWS. 



November 23, 1912. 



the percentage of water is as much as ninety, there is 

 little nitrification, probably because of the large occu- 

 pation of the air spaces of the Soil by water. The 

 greater ability of the clay soil to hold water caused this 

 to show a smaller range of good nitrification in relation 

 to the percentages of water present: at the same time 

 the process took place more actively in the clay than 

 in the sandy soil. 



In the investigation concerning the effect of chalk 

 and other substances on nitrification, the experiments 

 were conducted with a sandy soil deficient in lime, in the 

 same way as those in the trials with varying amounts of 

 water. It was found that chalk, of all the substances 

 tried, was favourable to the process to the greatest 

 extent, and that it exerted its helpful action soonest. 

 Burnt lime practically caused niti'ification to cease; i^ 

 harmful effect was greatest where most of it was used. 

 The process was hastened to a much smaller extent 

 by gypsum. Magnesium carbonate was similar in its 

 effects to chalk: while superphosphate of lime and 

 iron (ferric) chloride were favourable, though the action 

 of the iron salt was slow. Starch and sugar caused deni- 

 trification at first, and nitrification was recommenced 

 soonest where sugar was present: the action of the 

 sugar is parallel with that of molasses in soils manured 

 with sodium nitrate. Common salt and citric acid 

 proved to be quite inimical to nitrification. 



The investigation is of practical value in that it 

 shows or confirms that: excessive drying or wetting of 

 soils retards nitrification: the surface cultivation of 

 fallow land may be all the more valuable in that the 

 ■water which it helps to conserve is caused to be 

 present in amounts favouring nitrification: a growing 

 crop may reduce the amount of nitrates for the next 

 crop in two ways: by the simple removal of nitrates in 

 the produce, and by drying the land to such an extent 

 that subsequent nitrification is greatly retarded: and 

 that, where it can be done, a single flooding of fallow- 

 land, when the rainfall is low, may increase usefully the 

 fertility of the soil. 



There are other practical conclusions also to be 

 reached, in relation to the treatment or state of the 

 soil. Calcium carbonate is useful and prompt in its 

 action, as a soil dressing to promote nitrification: while 

 burnt lime may be employed for the same purpose b'.t 

 with caution — not near the time of sowing or during 

 the growing of the crop, and in smaller quantities than 

 chalk. Magnesium carbonate, gypsum and superphos- 

 phate of lime are favourable to nitrification; and the 

 same is true of red and brown soils, on account of 'he 



iron that they contain. Salt is among the substances that 

 delay nitrification. Lastly, the process is influenced 

 very unfavourably in sour soils, and the .■^.pplication of 

 undried green dressings, or of fresh stable manure to 

 wet soils may be expected to reduce for a time the 

 amount of nitrates present. 



SUGAR INDUSTRY. 



DISTANCE OF OANE-PLANTING. 



The following is taken from the Second Annual 

 Report of the Porto Rico Experiment Station, 

 1911-12:— 



All the plantings were made in furrows, the width 

 between rows varying as well as the distance between the 

 seed in the row. The object of the planting was to deter- 

 mine the proper distance between rows, between seed in the 

 row, and to determine the value of group planting, as against 

 continuous planting. Each plot is approximately ]-acre. 



It is seen from the above table [not reproduced] that 

 the cane in the clo.«e planting contained less sugar than that 

 from wide planting and that the cane was less mature, 

 neverthelesi there is a vjry great ditlerence in final results in 

 favour of the close planting, In fact there is but one case in 

 which there was nc increase in yield from close planting, 

 and this iu a total of beventeen experiments. The soil 

 where the 4-foot rows are planted was apparently in better 

 physical condition than that where the 6-foot rows were 

 planted, and this may account for a part of the difference in 

 yield; nevertheless after taking this into account there is 

 a marked difference in favour of close planting. 



A great many observations have been made, not only at 

 this Station, but also in plantations where experiments were 

 made in distance planting, of the apparent rate of growth of 

 cane, and almost without exception cane planted close grows 

 faster and develops faster than where planted wide apart. At 

 three months from planting there is generally a difference of 

 1 or 2 feet in the height of the cane, and the close planting 

 seems greener and more thrifty. This is contrary to the 

 usual opinion among Porto Ricans. They are inclined to 

 the opinion that where cane is planted very wide the indi- 

 vidual stalks will develop faster and stronger than the 

 thickly planted cane, and owing to the fact that the indi- 

 vidual canes have more room for root and leaf development. 

 The true explanation of the observed fact seems to be that 

 where there is a heavy stand of young cane it forms a pro- 

 tection against the wind, against the cold, and against the 

 trying effects of the sun. An added advantage is that the 

 cane soon covers and shades the ground, preventing the 

 evaporation of n:oi.?ture, and the development of weeds and 

 grasses. Cultivation, therefore, becomes much less expensive. 



These results and observations are quite in accord with 

 those of other cane-growing countries. In Hawaii rows are 

 usually placed 5 feet apart and the cane planted continuous 

 in the furrow. 



In Louisiana Dr. W. C. Stubbs made experiments 

 similar to those enumerated above and gives his conclusions 

 in Bulletin No. It, Second Series. He says (p. 365): 'The 

 above shows conclusively that there is nothing gained on the 



