REPORT OF TEE DIRECTOR 9 



SESSIONAL PAPER No. 16 



making the best possible use of barn-ynrtl niaiuiro, it is difficult to estimate the value 

 of this one item of information. 



When these experiments were planned, the opinion was very generally held that 

 untreated mineral phosphat'O, if very finely ground, wr.s a valuable fertilizer, which 

 gradually gave up its pliosphoric acid for the promotion of plant growth. Ten years' 

 experience has shown that mineral phosphate, untreated, is of no value as a fertilizer. 



Sulphate of iron, which at the time these tests were begun, was highly recom- 

 mended, as a means of producing increased crops, has also been proven to be of very 

 little value for this purpose. 



Common salt, which has long had a reputation with many farmers for its value as 

 a fertilizer for barley, while others disbelieved in its efficacy, has been shown to be a 

 valuable agent for producing an increased crop of that grain, while U is of much 

 less use when applied to crops of spring wheat or oats. Land plaster or gypsum has 

 also proven to be of some value as a fertilizer for barley, while of very little service 

 for wheat or oats. Soijae light has also been thrown on the relative usefulness of single 

 and combined fertilizers. 



CHANGES IMADE IN THE EXPERIMENTS. 



After ten years' experience had demonstrated that finely-ground, untreated mineral 

 phosphate was of no value as a fertilizer, its use was discontinued in 1898. Prior to 

 this it had been used in each set of plots in ISTos. 4, 6, 6, 7 and 8, in all the different 

 series of plots, excepting roots. In 1898 and 1899, similar weights of the Thomas' 

 phosphate were used in place of the mineral phosphate, excepting in plot 6 in each 

 series. In this plot the Thomas' phosphate was used in 1898 only. 



After constant cropping for ten or eleven years, it was found that the soil on these 

 plots to which no barn-yard manure had been applied was much depleted of humus, 

 and hence its power of holding moisture had been lessened, and the conditions for 

 plant growth, apart from the question of plant food, had on this account become less 

 favourable. In 1899 the experiments were modified and an effort made to restore some 

 proportion of the humus and at the same time gain further information as to the value 

 of clover as a collector of plant food. In the spring' of that year ten pounds of red 

 clover seed per acre was sown with the grain on all the plots of wheat, barley and oats. 

 The young clover plants made rapid growth, and by the middle of October there was 

 a thick mat of foliage varying in height and density on the different plots, which was 

 ploughed under. No barn-yard manure was applied on plots 1 and 2 in each series 

 from 1898 to 1905. 



In 1900 all the fertilizers on all the plots were discontinued, and from then to 1905 

 the same crops were grown on all these plots from year to year without fertilizers, 

 sowing clover with the grain each season. In this way some information has been 

 gained as to the value of clover as a collector of plant food, and also as to the unex- 

 hausted values of the different fertilizers which had been used on these plots since 

 the experiments commenced. In 1905 and 1906 all the fertilizers were again used as 

 in 1898. 



SPECIAL TREATMENT OF PLOTS OF INDIAN CORN AND ROOTS. 



As it was not practicable to sow clover with the Indian corn and root crops, the 

 sowing of these latter crops was discontinued in the spring of 1900 and clover sown 

 in their place in the proportion of 12 pounds per acre. The clover on these plots made 

 strong growth, so strong as to necessitate twice cutting during the season, the cut 

 clover being left on the ground in each case to decay and add to the fertility of the 

 soil. The clover was left over for further growth in the spring of 1901, and ploughed 

 \inder for the roots about May 10, and for corn about the middle of that month. Then 

 roots and Indian corn were again sown. In 1902 crops of Indian corn anJ roots were 

 grown on these plots. In 1903 the land was again devoted to clover and was in Indian 

 corn and roots again in 1904 and each year since. 



