lo Sept., Tgu.] Some Results in FaUoivitii:^ Land. 



5^0 



While the figiiifs for Alice Spriigs cannot be regarded as tvpical. 

 being, according to ligun-s published by the Meteorological Office,* about 

 one-half greater thin those tor the drier wheat areas, still the rate ot 

 e\aporation in Australia is undoubtedly \ery great, and there is almost 

 no country where an equal need for fallowing occurs, nor where greater 

 saving in .soil moisture may be expected from good cultixation. 



Relation of Fallowing to Nitrates. 

 Leaving the effect of fallowing upon moisture, the nitrate contents of 

 the plots next call for notice. Table VI. states the results obtained in 

 lbs. per acre of nitr.ite nitrogen for each plot at the different dates of 

 .sampling. Depth, i8 inches. 



Table VI. 



Up to i6:h October, the worked and the neglected fallow had received 

 the same treatment, and the results show that the worked fallow had no 

 -original advantage. Nevertheless, at the end of February, the neglected 

 fallow contained just 39 per cent, of the nitrate present in the worked plot, f 

 The latter was seen to be much moister during the latter half of the experi- 

 ments, and the extra nitrates are proliably due in large measure to this extra 

 moisture encouraging nitrification. This is in accord with the results of 

 •experiments recently reported in this JoumalX Sufficient moisture will be 

 of greatest benefit in aiding nitrification during the hot months of the year. 

 In addition to the extra water present, the better aeration of the worked 

 fallow would also encourage the production of nitrates. 



Nitrates Used by Crop. 

 On the cropped plot the nitrate content was only a trace at the date of 

 the first sampling. Comparing it with the fallow plots, this could not be 

 due to lack of moisture, as at that date the moisture content of each plot 

 Avas approximately identical. It appears that the nitrates of this plot had 

 been absorbed to supply the wants of the growing crop. Apparently the 

 crop in the earlv part of its growth was taking all the nitrates it could find. 

 This fact indicates the importance of nitrates in the soil, and the probability 

 that the supplv often fails to meet the demand. 



Results Obtained Abroad. 

 Similar results showing the demand for nitrates by cereals were obtained 

 h-, America bv King. § On 20th June (summer) a .strip of land 8 by 120 

 feet in a growing oat crop was cleared by shaving everything off just beneath 

 the surface. At this date nitrates were determined, on the cleared strip and 

 also on the adjacent land growing oats, and similar determinations were 

 made again after nineteen da vs. Table VII. gives the results in lbs. of 

 nitrate nitrogen for each date at successive depths of i foot. 



* Commonwealth Y tar- Book. '911. 



t This is exclusive of 25 lb. nitrate nitrogen in the worked fallow and i\ ll>. in the neglected fallow 

 iound below the 18 inch level at the last sampling. 

 t May. 1912. p. 275. 

 § Univ. of Wisconsin. Agric. Exp. St. Bui. 93. 



