2 parts water. culated as culated as 1 part honey, Polarization. Direct After inversion. Dextrose. cane sugar. Reading. Temp. Reading. Temp. At 86° C. FIELD EXPERIMENTS WITH PHOSPHATES. The cost of phosphoric acid in fertilizers varies greatly according to the material in which it is purchased. Thus in superphosphates prepared from bone black it costs at present about 8 cents a pound, in dissolved South Carolina Rock between 5 and 6 cents, in Bolivian Guano a little over 4 cents and in Grand Cayman's Phosphate and ground South Carolina Rock about 3 cents. Without doubt the more expensive superphosphates applied in moderate quantity will generally make a larger yield on land deficient in phosphoric acid, than the same quantity of the cheaper raw phosphates or natural phosphates as they are called. But since almost three times as much phosphoric acid can be bought for the same money in raw phosphates as in superphosphates it becomes a very practical question whether their prices stand in close relation to their agricultural value; whether for some crops instead of using a small quantity of superphosphate it may not pay to use a larger quantity of some other less soluble phosphate which costs less per pound. Last year a single experiment on this point was carried out with the assistance of Mr. W. I. Bartholomew of Putnam. The same experiment substantially has been repeated this year with the coöperation of the following gentlemen: Mr. W. I. Bartholomew, Putnam. Mr. W. R. Fish, Mystic Bridge. Mr. C. A. Sill, Saybrook. Mr. C. S. Andrews, Jr., New Britain. Mr. E. A. Russell, Suffield. Mr. Robert Aitken, Shaker Station. Mr. G. F. Platt, Milford. Mr. Edwin Hoyt, New Canaan. The results are given in detail on the following pages. The general plan of experiment was as follows: Land was in all cases selected which in the judgment of its owner was uniform in quality, which had all been cultivated alike and which had not been manured for some years. Only on such land could it be expected that one plot would give the same yield as another plot similarly treated and that a fertilizer would considerably increase the yield. Over the whole experimental field was broadcast a liberal quantity of nitrogenous matter and potash salts-more than sufficient for a maximum crop. This was essential in order that the yield should be limited by the quantity of phosphoric acid in the soil and not by either nitrogen or potash. The field was then divided into 7 or more plots which were designated by letters A, B, C, etc., and on which the different phosphates were applied. The phosphates chosen for comparison were : 1. Dissolved Bone Black, containing 16.53 per cent. of phosphoric acid; 2. A finely pulverized phosphatic rock, from Grand Cayman Island in the Caribbean Sea, containing considerable iron and alumina with 26.22 per cent. of phosphoric acid, placed at our disposal by N. B. Powter, Esq., 181 Pearl street, N. Y.; 3. Thomas-Slag, a byeproduct of the steel manufacture, furnished by Paul Weidinger, Esq., No. 76 Pine street, N. Y., and containing 19.6 per cent. of phosphoric acid. 4. Ground South Carolina Rock, containing 25.5 per cent. of phosphoric acid. 5. Bolivian Guano. A phosphatic guano from the West Indies, furnished by the Quinnipiac Co. of New London, containing 17.2 per cent. of phosphoric acid, The analyses are given on pages 36 and 37 of this Report (Part I). On the first plot a quantity of Dissolved Bone Black was used which it was believed would insure a fair yield and yet would not be in excess of the needs of a full crop but rather slightly deficient. A single plot was given to each of the other phosphates and they were used in such quantity that the cost of each was just equal to the cost of the dissolved bone black on the first plot. Two or more plots received no phosphate and thus served to show the natural capacity of the soil itself to supply phosphoric acid to the crop. The land was planted and cultivated as usual and the weight of the crop at harvest was taken in almost all cases by a representative of the Station. A fuller discussion of the reasons for the particulars of the experiment may be found in the last Report of this Station. one. EXPERIMENTS CARRIED OUT BY MR. W. I. BARTHOLOMEW, PUTNAM. Experiment No. 1.-With Indian Corn. The first experiment is a repetition of the trial made last year and described in our last Report, page 110. The land used for the experiment is high, gently sloping to the southwest. The soil is a dark loam, moist, with clayey sub-soil. In the fall of 1886 the land had been sown to rye, which was badly winterkilled. In 1887 it was used for an experiment like the present The details of that experiment are as follows. After plowing, 200 pounds of muriate of potash and 100 pounds of sulphate of ammonia were broadcast on the acre, the soil was well pulverized with a Thomas smoothing harrow and laid out in seven plots, each 10 rods long and 2 rods wide, containing one-eighth of an acre. On these plots a small variety of flint corn, Rhode Island White Cap, was planted in hills about 3 feet and 3 inches apart each way making 10 rows containing 500 hills in each plot. The phosphates were put in the hill. The general arrangement and the quantities of the phosphates used are shown in the diagram. The cost of the phosphatic material used on each plot was the same. At hoeing time the corn was thinned to five stalks to a hill. The year was uncommonly favorable for the corn crop. It was cut Sept. 20, and husked and weighed Oct. 14th. The yields. will be spoken of presently. This year the land was plowed again. 320 pounds of muriate of potash and 160 pounds of sulphate of ammonia were broadcast on the same field, but no phosphates were used. The same variety of maize was planted, the date and the method of planting and cultivation were precisely the same as last year. This experiment then should show whether the phosphates used last year and not then removed by the crop were still available for corn and how the different phosphates compared in this regard. The crop grew without accident. A short but violent rain-fall on the evening of June 15 (nearly an inch of water fell in about half an hour) washed the surface somewhat, running off between the rows, but could not have very seriously interfered as the fertilizers had been pretty well worked in previously. During the summer it was evident that the plot on which Thomas-Slag had been used the year before was doing best and the one which had Grand Cayman's stood next, both decidedly B Grand Cayman's Phosphate. 56 pounds. C No Phosphate. D Thomas-Slag. 67 pounds. E South Carolina Rock. 70 pounds. F No Phosphate. G Gypsum. 16% pounds. The plots are 2 rods wide and 10 rods long and contain one-eighth of an acre each. The hills of corn are one-fifth of a rod apart each way and the outside hills are one-tenth of a rod from the edge of the plot. Between the plots are spaces one-fifth of a rod wide and in the middle of each space is a single row of potatoes. The whole ground under experiment is surrounded by a double row of potatoes. |