478 Field Experiments on Clover-Seeds. 



3. That mineral superphosphate, or dissolved bone-ash, has 

 had a less beneficial effect than sulphate of lime. 



4. That common salt diminished the produce to a considerable 

 extent. 



5. That nitrate of soda alone, and still more so sulphate of 

 ammonia, produced a very considerable increase in the grass- 

 crop. 



6. That the addition of soluble phosphate of lime (mineral 

 superphosphate) to nitrate of soda had a very beneficial effect. 



7. That the highest produce was obtained on Plot 10, on 

 which mineral superphosphate and muriate of potash had been 

 used. The produce of 10 tons 2\ cwts. per acre is large. It is 

 remarkable that whilst Plot 3, manured with mineral super- 

 phosphate, and Plot 6, manured with muriate of potash, gave 

 precisely the same produce, which was somewhat less than that 

 on the unmanured part of the field, the mixture of both manures 

 on Plot 10 gave the largest weight of mixed clover and grass per 

 acre of any of the 10 experimental plots. 



It must be confessed that some of the facts brought out in 

 these experiments are opposed to what we know of the efficacy 

 of fertilizers such as superphosphate and gypsum, and I do not 

 believe for a moment that the latter is superior to the former as 

 a manure for " seeds." 



It is well known that very soluble manures, such as muriate 

 of potash or even common salt, occasionally have rather an 

 injurious than beneficial effect on vegetation ; but it is difficult 

 to understand why two manures, which each separately gave no 

 increase at all, but rather diminished the crop, should, when 

 mixed together, produce such a beneficial result as in Plot 10. 



It is much to be regretted that we have in these experiments 

 onh' one plot left unmanured. This is a great defect, for it 

 leaves us altogether in the dark with regard to the natural 

 variations in the productive powers of different portions of the 

 same experimental field. In future experiments I will take care 

 to have left three plots unmanured : one on each side of the 

 manured plots, and one right in the midst of them. Many of 

 the anomalies which so much perplex the experimenting farmer, 

 I am convinced are due either to inequalities in the plant, or to 

 essential differences in the staple, or agricultural condition of the 

 several experimental plots. We may do our best to select in a 

 field half-an-acre or an acre of what appears to be a perfectly 

 uniform piece of clover-seeds, and yet the actual weighings ol the 

 produce will frequently show that we have failed to pick out two 

 plots precisely on an equality as to plant. We should, therefore, 

 have at least two unmanured portions, and I believe three will be 



