FIELD CROPS. 329 



soil. In the high moisture series the weight of the substance above ground 

 ranged from 150 to 200 per cent of the weight of the root system. 



The experiments with wheat liliewise showed that in general during the 

 early vegetative period a larger root system was developed in the unfertilized 

 than in the fertilized soil. The length of the roots as well as the weight of 

 the root material was the greater in the unfertilized pots. The thickness of 

 the roots in the clay soil was apparently not influenced by the fertilizer applied, 

 but in the sandy soil the weight of the root substance was in all cases higher 

 in the fertilized than in the unfertilized pots. A unit weight of root material 

 produced a gi*eater quantity of plant substance above ground in the fertilized 

 than in the unfertilized' soil. The production of plant material above ground 

 per unit weight of root substance was increased considerably by a high moisture 

 content and soil compactness. As in the work with barley, the larger root 

 systems were produced in the series of high soil moisture content, but the 

 greater absolute weight of root substance was secured in the dry series of 

 tests. The influence of soil moisture was in general the same for the two 

 crops and the author lays stress upon the fact that the favorable early devel- 

 opment of the underground and aboveground parts of the plants is dependent, 

 to a very great extent, upon the soil moisture. 



In studying the influence of soil compactness it was found that in the loose 

 clay soil the plants produced the longest main roots, while in the compacted 

 clay the lateral roots were the longer and the more numerous. The largest 

 quantity of underground substance in both clay and sand was secured in the 

 loose soil with high moisture content and in the compacted soil with low 

 moisture content. Generally the absolute weight of root substance was corre- 

 lated with the size of the root system but in the dry clay series the largest 

 main roots were produced in the loose soil, while the largest weight of root 

 substance was obtained in the compacted soil. The data for both barley and 

 wheat show that the weight per unit of root length was the greater in the com- 

 pacted soil series. 



Field experiments, 1910 (Dept. Agr. and Tech. Instr. Ireland Jour., It 

 {1911), No. 2, pp. 238-302). — These pages report the resiflts of field experi- 

 ments with barley, hay, potatoes, mangels, oats, turnips, and wheat, each 

 tested at a number of different farms. 



A comparative test of Danish Archer barley grown from Jreshly imported 

 seed and also from seed gi'own in Ireland for 4 years showed no significant 

 difference in yield or quality. Experiments testing the effect of applications 

 of sulphate of ammonia, superphosphate, and kainit, alone and in various 

 mixtures, indicate that the use of a mixture of 1 cwt. sulphate of ammonia, 3 

 cwt. of superphosphate, and 3 cwt. kainit per acre is the most remunerative 

 on barley ground. On soils that are too rich or on meadow land the use of 

 from 2 to 3 cwt. of kainit per acre proved efficacious in preventing an over- 

 growth of straw. 



In tests with hay conducted at 15 different points, applications of farmyard 

 manure, nitrate of soda, superphosphate, and kainit singly and in various com- 

 binations were followed by increases in the returns secured ranging from 7 

 cwt. 3 qrs. after 1 cwt. nitrate of soda to 15 cwt. 3 qrs. after an application of 

 1 cwt. nitrate of soda, 2 cwt. superphosphate, and 2 cwt. kainit. The use of 

 nitrate of soda alone is not recommended for hay under ordinary conditions. 



Applications of farmyard manure, sulphate of ammonia, superphosphate, 

 muriate of potash, and sulphate of potash singly and in various mixtures to 

 potatoes were followed by increases in the yields ranging from 4 tons 5 cwt. 

 after an application of 15 tons of farmyard manure to 7 tons 3 cwt. after the 

 application of a mixture of 15 tons farmyard manure, 1 cwt. sulphate of am- 



