1909.] Summary of Agricultural Experiments. 155 



ammonia, Norwegian nitrate of lime, calcium cyanamide, and lime 

 nitrogen. The results are given in detail, and are discussed under 

 several heads : — (i) The increased yields due to different forms of 

 nitrogen ; (2) the quantities of nitrogen taken up by the crops from 

 each kind of manure applied ; (3) a comparison of the increase in crops 

 with the utilisation of nitrogen ; (4) the effect of application in autumn 

 and spring; (5) the effect of top dressing spring crops; and (6) the 

 influence of nitrogen on the starch and sugar content of potatoes and 

 roots. 



It is considered that nitrate of soda has given the best average 

 results, while the relation of sulphate of ammonia to nitrate of soda was 

 as 90 : 100. The Norwegian nitrate of lime acted on the average in 

 exactly the same way as nitrate of soda. In the field experiments the 

 increase in the crops was 96 as compared with 100 for nitrate of soda. 

 In experiments with grain, however, its action was somewhat inferior, 

 but further trials will be necessary to ascertain whether this is regularly 

 the case. Calcium cyanamide has not given satisfactory results on 

 sandy soils or sandy loams, but on heavier soils it has come up to 

 expectations except as regards roots. 



In the case of autumn-sown grain (rye and wheat) the highest 

 yields were obtained when all the nitrogen was applied in the form 

 of a top dressing of nitrate of soda in spring. No great difference was 

 observed on the heavier soils between the effect of nitrate applied in the 

 spring and sulphate of ammonia applied in the autumn, but in the 

 case of light soils the difference was very great, as under certain cir- 

 cumstances nearly the whole of the manure may be lost during the 

 winter. These manures should therefore only be applied in autumn 

 where it is necessary to strengthen the plants for the winter, and 

 even then only on moderately retentive soils, as otherwise it is money 

 thrown away. 



Milk Production of Cows. (Bericht des Denis chen Landwirtschafts- 

 rats, Reichsamt des Inn em. Untersuchungen iiher die Wirkung des 

 Nahrungsfettes auf die Milchproduktion der Kiihe. 1907.). — This 

 Report by Professor Kellner, of the Mockern Agricultural Experiment 

 Station, gives the result of experiments carried out at ten German 

 experiment stations with the assistance of the Ministry of the Interior. 



The experiments were carried out under conditions of ordinary 

 farming at each centre with two groups of ten cows each, so selected 

 as to be practically identical as regards yield, quality of milk, and 

 live weight. Both groups were to be fed for one period with food poor 

 in fat, then one group was to receive food rich in fat, and afterwards 

 to revert to the poor food. In some cases, however, the whole number 

 were fed first on poor food, tnen on rich food, and again on food 

 poor in fat, the choice of the method being left to the experiment 

 station. Each period covered about 30 days. 



The results of these experiments may be summarised as follows : — 



1. The substitution of a part of the digestible carbo-hydrates in the 

 food of milch cows by an equivalent quantity of digestible fat, not 

 exceeding 1 kilo, of fat per 1,000 kilos, of live weight, has, with the 

 great majority of the animals, somewhat diminished the yield of 

 milk as well as the weight of fat in the milk. 



2. In one out of the ten experiments, a small increase in yield 



M 2 



