44^ '^!^t'^^' LAWES AGRICULTURAL TRUST icai rials Rothamsted Experimental Station Harpenden Guide to the Experimental Plots 1913 PRICE - ONE SHILLING NET LONDON JOHN MURRAY, ALBEMARLE STREET, W. 1914 ' •: :\^J')':^^- . f LAWES AGRICULTURAL TRUST Rothamsted Experimental Station Harpenden Guide to the Experimental Plots 1913 PRICE - - ONE SHILLING NET LONDON JOHN MURRAY, ALBEMARLE STREET, W. 1914 COMMITTEE OF MANAGEMENT Sir J. H. THOROLD, Bart., LL.D. (Chairman). H. MULLER, LL.D., F.R.S. (Treasurer). H. E. ARMSTRONG, LL.D., F.R.S. R. H. BIFFEN, M.A. H. T. BROWN, LL.D., F.R.S. J. B. FARMER, M.A., F.R.S. A. B. RENDLE, D.Sc, F.R.S. J. A. VOELCKER, M.A., Ph.D. DIKECTOE E. J. RUSSELL, D.Sc. All rights reserved CONTENTS Introduction ...... General Plan of the Experimental Fields The Rothamsted Soil ..... Agdell Field — Crops grown in Rotation Barn Field — Mangolds ..... Meteorological Observations .... The Park — Grass Land mown for Hay every year Broadbalk Field — Wheat .... Hoos Field — Barley ..... „ Leguminous Plots „ Potato Plots — Residue of Manures „ Inoculation of Leguminous Plants „ Wheat after Fallow Little Hoos Field — Residual Value of Manures The Incorporated Society for Extending the Rothamsted ments in Agricultural Science EXPERI- PAGK 4 6 7 7 11 17 19 29 35 41 41 44 45 45 48 INTEODUCTION Mr (afterwards Sir) John Bennet Lawes was the founder of the Roth- amsted Experimental Station. He began experiments with various manurial substances, first with plants in pots and then in the field, soon after entering into possession of the estate of Rothamsted in 1834. In 1843 more systematic field experiments were begun, and the services of Dr (afterwards Sir) J. H. Gilbert were obtained as Director, thus starting the long association which only terminated with the death of Sir John Lawes in 1900, followed by that of Sir Henry Gilbert in 1901. For many years the Rothamsted Experimental Station was not con- nected with any external organisation, but was maintained entirely at the cost of Sir John Lawes. In 1889 he constituted a trust for the continuance of the investigations, setting apart for that purpose the laboratory (which had been built by public subscription, and presented to him in 1855), certain areas of land on which the experimental plots were situated, and £100,000. By the provisions of the trust-deed, the management is entrusted to a committee nominated by the Royal Society (four persons), the Royal Agricultural Society (two persons), the Chemical and Linnean Societies (one each), and the owner of Rothamsted. In 1906 Mr J. F. Mason, M.P., presented the Committee with £1000 for the building and equipment of the "James Mason" Bacteriological Laboratory, together with a grant towards its maintenance. In 1907 the Goldsmiths' Company made a grant of £10,000, the income of which is devoted exclusively to the investigation of the soil. The Permanent Nitrate Committee have also made a grant of £2000 to the endowment. The Society for extending the Rothamsted Experiments, founded in 1904, has also collected donations amounting to £3400 and annual subscriptions of over £130. This Society was in 1909 incorporated under the Board of Trade, thus giving it the power to hold money in trust for the purposes of the Rothamsted Experiments. During the year 1911 a scheme was published from the Board of Agriculture for the encouragement of agricultural research with funds provided by the Development Commission, and this scheme established or assisted a certain number of institutes for fundamental research, each dealing with one great branch of the subject. The Rothamsted Experi- mental Station is recognised as the Institute for dealing with Soil and INTRODUCTION 5 Plant Nutrition problems. In accordance with this scheme a capital grant of £3100 was made, and a maintenance grant of £2500 for the current year, and it is expected that an annual grant of this amount will be made to the Station in future. Certain scholarships have also been instituted to provide the training in research work for men who have already qualified in pure science and are desirous of taking up an agricultural career. The holders of some of these scholarships do their work at Rothamsted. The field experiments, which began in 1843, have on some of the plots been continued without break or alteration up to the present day ; on the Broadbalk wheat field certain rearrangements were made in 1852, in which year also the barley experiments on the Hoos field began. The legumin- ous crops on the Hoos field were started in 1848 ; the experiments on roots have been continued on the same field since 1843, and on the same plan since 1856. The grass plots began in 1856, and the rotation experiments in 1848. It should be remembered that the object of the Rothamsted experi- ments is to study the soil and the plant, and only indirectly to find the most paying method and manuring ; hence neither the nature nor the quantities of material applied are to be taken as indicating the manures to be used in practice. A THE ROTHAMSTED SOIL The Rothamsted soil was described by Lawes in 1847, as follows : — "The soil upon which my experiments were tried consists of rather a heavy loam resting upon chalk, capable of producing good wheat when well manured ; not sufficiently heavy for beans, but too heavy for good turnips or barley. The average produce of wheat in the neighbourhood is said to be less than 22 bushels per acre, wheat being grown once in five years. The rent varies from 20s. to 26s. per acre, tithe free."" It is fairly uniform in the different fields, and consists essentially of a heavy loam containing little coarse sand or grit, but a considerable amount of fine sand and silt, and a large body of clay. In consequence, the soil has to be worked with care, becoming very sticky and drying to im- practicable clods if moved when wet. It " runs together "" if heavy rain falls after a tilth has been established, and then dries with a hard, unkindly surface, these difficulties being much exaggerated on the plots which have been farmed for a long time without any supply of organic matter in the manures. The most notable feature in the Rothamsted soil is the amount of calcium carbonate in the surface layer ; analyses of the earliest samples available (1856) show more than 5 per cent, in the surface soil of Broad- balk field. The subsoil below the depth of 9 inches contains little or no calcium carbonate, and this fact, together with the varying proportion in the surface soil, indicate that the original soil was almost devoid of calcium carbonate, and that the quantity now found in the surface soil has all been applied artificially. AGDELL FIELD Crops grown in Rotation. The Agdell field, which was put under experiment in the year 1848, differs from the other Rothamsted fields in that it is farmed on a four- course rotation of Swedes, barley, clover (or beans) or fallow, and wheat, instead of growing one crop continuously. It is divided into three main plots, one of which (O) has received no manure, the second (M) mineral manures only, and the third (C) a complete manure, containing the same minerals, but also nitrogen in the form of rape cake and ammonium -salts. The manures are applied to the Swedes only, the other three crops of each course being grown without manure. Each of the three plots is further subdivided : — Half the pldts carry clover or beans as the third crop of the course, and half the plots are bare fallow. This shows the effect of introducing the leguminous crop into the rotation, as compared with the bare fallow. On this field the long-continued cropping without manure on O affects the successive crops in the rotation very differently. The Swede crop is least capable of growing in the impoverished soil, and is reduced to less than a ton per acre ; the clover and barley crops are also small, but the deep-rooted wheat crop is comparatively little affected, and yielded as much as 24-2 bushels per acre in 1911, the sixty-fourth year without any ■Plan of the Plots in Agdell Field on which Experiments have been made on Four-Course Rotation. 1848 and onwards. Clover Fallow "^ PLOT 2 PLOT 1 PLOT 4 PLOT 3 PLOT G PLOT 5 Clover Fdlldiw ^ , C. Complete Manure for Root Crops. As " M," and 200 lb. Ammonium-salts, and 2000 lb. Rape Cake per acre. M. Minerals only for Root Crops, 500 lb. Superphosphate, 500 lb. Sulphate of Potash, 100 lb. Sulphate of Soda, 200 lb. Sulphate of Magnesia, per acre. O. Unmanured. Total area of ploughed land, about 3 acres. Area of each of the 6 divisions, | acre. The 2 lower divisions, Unmanured continuously (Plots 5 and 6). The 2 middle divisions, Mineral Manure, for the Roots, each Course (Plots 3 and 4). The 2 upper divi', only, the clover shows little or no effect on succeeding crops, because there its growth is too small to leave behind any residue of nitrogen. 10 AGDELL FIELD Unmanured Minerals only, no Nitrogen Complete Manure Fig. 1. — Effect of Manure upon Crops grown in Rotation. Total Produce. Average of Five Courses (1884-1903). Swedes in 100 cwt. ; Barley and Wheat in 1000 lb. ; and Clover in 10 cwt. Table III. — Crops grown in rotation, Agdell Field. Effect of the largest Clover or Bean Crop on the following Wheat Crop. Total prodvjceper acre. Clover, 1910. Wheat, 1911. Beans, 1862. Wheat, 1863. After Fallow. After Clover. Difference due to Clover. After Fallow. After Beans. Difference due to Beans. O. Unmanured M. Mineral Manure . C. Complete Manure Cwt. 17-4 64-1 76-6 Lb. 3876 5338 5454 Lb. 4052 6292 6163 Per cent. + 4-5 + 17-9 + 13-0 Lb. 3603 4033 5755 Lb. 7222 7910 8792 Lb. 5281 6090 7674 Per cent. -26-9 -23-0 -12-7 Table IV. — Crops grown, in rotation., Agdell Field. Effect of Clover or Beans on the following Wheat Crops, Total produce per acre. Clover Crops.* Wheat, t Bean Crops, t Wheat. § After Fallow. After Clover. Difference due to Clover. After Fallow. After Beans. Difference due to Beans. O. Unmanured M. Mineral Manure . C. Complete Manure Cwt. 14-0 47-0 50-1 Lb. 4028 5147 5493 Lb. 3696 6052 6093 Per cent. - 8-2 + 17-6 + 0-9 Lb. 1888 2615 3177 Lb. 4907 5528 6092 Lb. 4373 5447 5929 Per cent. -10-9 - 1-5 - 2-7 * 7 yea H (1874, 18,v2, 1866, 1894, 1W02, 1906, ;tiid 1910). t 7 years (1876, 18-<3, 1887, 1895, 1903, 1907, and 1911). X 8 years (1854, 1858, 1862, 1-66, 1870, 1878, 1890, and 1898). S 8 year* (1855, 1859, 1863, 1867, 1871, 1879, 1891, and 1899). CROPS IN ROTATION 11 The diagram. Fig. 2, shows in a graphic form the benefit the whole rotation receives from the growth of clover, even when the root crop receives nitrogenous manures. Wheat Clover After Clover. After Fallow. Fig. 2.— Comparative Effect of Clover or Bare Fallow on the succeeding Crops in the Rotation. Total Produce— In 1000 lb. for Clover, Wheat, and Barley, and in 100 cwt. for Roots. BARN FIELD Mangolds. The experiments upon mangolds began in 1876, but the land had been receiving similar manures for other root crops since 1856. The field is divided longitudinally into eight strips running the whole length of the field ; each of these strips receives one manure throughout its length ; farmyard manure alone on Strip 1, and in combination with superphosphate and sulphate of potash on Strip 2, nothing on Strip 8, superphosphate alone on Strip 5, superphosphate and sulphate of potash B. — Plan of the Plots in Barn Fidd on which Experiments have been made with Root Crops. 1843 and onwards. Valley. Mangolds^ unmanured. Total area of ploughed land, about 8 acres. n, 2, 5, 6, 7, and 8, of each Series, rather over f acre. Arpn nf Pln^R J ^' ^^^ each Series, about ^V acre. Area ot i-lots ^^^^^ ^^^j^ g^^j^^^ ^^^^^^ ^ ^^^^ \9, rather over i% acre. The double lines indicate division paths between plot and plot. MANGOLDS 13 on Strip 6, and complete minerals, including sulphate of magnesia and common salt, on Strip 4. The strips are then subdivided into plots by cross-dressings of nitrogenous manures ; nothing on the O series, nitrate of soda on Series N, ammonium-salts on Series A, rape cake on Series C, and a combination of ammonium-salts and rape cake on Series AC. Table V. — Experiments on Mangolds, Barn Field, beginning 1876. Quantities of Manures per acre per annum. strip Manures. Nitrogenous Manures ruuni all the Strips. ng across i Series O. N. A. AC. c. strip. F / \ \ \ 150 / ^^ \ / \ / / / • y v .C \ ?^ ^ /y ^s \ \^ 100 \ / V %} \ \ ■ yy ^> 'k /.^ / • (5 >>> »in .4 f 0^ e ^\ ,- '^^^* Plot 13.* 14 tons Dung 1905, and every fourth year. 6 cwt. Fish Guano 1907, and every fourth year.f BROADBALK FIELD Wheat The experiments on the continuous growth of wheat were begun in the Broadbalk field in 1843, but for the first eight years the manuring was of a varied description, so that only three of the plots have received the same treatment during the whole period of seventy years. The plots as seen to-day began in 1852, since which time the few changes in manuring have been matters of detail and not of principle. The chief difficulty experienced in growing wheat continuously is that of keeping the land clean ; not only does the crop occupy the ground for the greater part of the year, and so leave little opportunity for cleaning operations, but the weeds whose habit of growth is favoured by the crop tend to accumulate from year to year. Thus in spite of repeated hand-hoeings, some weeds, like the "Black Bent" grass, Alopecurus agrestis^ are kept under with the greatest difficulty. On Plot 3 wheat has been grown without manure every year since 1843, for four years previously no manure had been applied to the field, so that the present crop is the seventy-fourth without manure. After a drop in production during the first few years, the yield has been practically constant for the last fifty years, fluctuating only with the season, and showing no immediate prospect of declining. The average crop over this period has amounted to about 12 J bushels per acre, approximately equal to the average yield, taking the whole world over. Effect of Nitrogenous Manures. Plots 6, 7, and 8 should be compared with Plot 5, since all receive the same mineral manures, but different amounts of nitrogen as ammonium- salts. Plot 5, which receives the minerals but no nitrogen, grows very little more than the continuously unmanured plot ; its average over the whole period is only 14*5 bushels, as against 12*6 without manure of any descrip- * The southern half of Plot 13 ref-eived a dressing of 2000 lb. of ground lime in 1907. t The fish guano was applied in 1910 instead of 1911. 30 BROADBALK FIELD Table XV. — Experiments on Wheat, Broadbalk Field. Manuring of the Plots per acre per annum, 1852 and sinx^e. Plot. Abbreviated Description of Manuring. Nitrogenous Manures. Mineral Manures. Is (3 li a f .-2 'I 1 II 2 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Farmyard Manure .... Unraanured Minerals Single Ammonium-salts and Minerals Double do. do. Treble do. do. Single Nitrate and Minerals Double Ammonium-salts alone . Do. and Superphosphate . Do. do. and Sulph. Soda . Do. do. and Sulph. Potash Do. do. and Sulph. Mag. . Double Amm. -salts in autumn, and Minerals Double Nitrate and Minerals ' Minerals alone, or Double Amm.-salts/ J alone, in alternate years . . \ Rape Cake alone .... Tons. 14 ... ... Lb. 1889 Lb. 275 " ... 5.50 Lb. 200 400 600 400 400 400 400 400 400 400 Owt. 3 '5 3-5 3-5 3-5 3-5 3*-5 3-5 3-5 3-5 3-5 3-5 3-5 Lb. 200 200 200 200 200 ... 200 200 200 200 Lb. ioo 100 100 100 100 366-5 100 100 100 Lb. ioo 100 100 100 100 280 100 100 100 Table XVI. — Experiments on Wheat, Broadhalk Field. Produce of Grain and Straw per acre. Average over 61 years (1852-1912); and over 10 years (1903- 1912) ; also Produce in 1911. Plot. 2 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Abbreviated Description of Manuring. Dressed Grain. > Farmyard Manure .... Un manured Minerals Single Ammonium-salts and Minerals Double do. do. Treble do. do. Single Nitrate and Minerals Double Ammonium-salts alone . Do. and Superphosphate . Do. do. and Sulph. Soda Do. do. and Sulph. Potash . Do. do. and Sulph. Mag. Double Amm.-salts in autumn, and Mmerals Double Nitrate and Minerals .... "I Minerals alone, or Double Ammonium-salts/* / alone, in alternate years . . . • It Rape Cake alone + Bush 35-2 12-6 14-5 23-2 32-1 3d -6 20-0 22-9 29-1 31 0 28-8 29-9 14 -9 29-9 25-4 2^ Bush 32-8 ]0-0 12-5 19-0 27-9 33-8 26-0 16-3 17-1 24-6 28-7 22-0 26-4 30-2 12-9 27-6 22-8 Bush 35-2 12-5 14-8 17-2 25-6 36-4 29-9 22-8 20-1 27-0 29-7 24-1 24-1 40-4 13-8 27-3 28-6 Straw. Cwt. 34-8 10-3 12-1 21-4 32-9 41-1 18-4 22-3 28-0 31*5 28-0 29-7 13-0 29-5 25-7 Cwt. 38-2 9-3 11-9 20-7 32-3 42-1 28-7 167 20-2 26-2 33-1 24-1 29-0 39-1 12-4 29-7 24-8 Cwt. 36-9 9-8 12-8 17-9 27-6 35-7 29-0 17-2 15-2 20-6 27-4 18-9 22-3 42-4 11-7 24-6 24-7 by Minerals. t Produce by Ammonium-salts. X 20 years (1898-1912). WHEAT 31 Total Produce per Acre 7000 lb. - 6000 SOOO 4000 200O Grain per Acre, lb. Straw per Acre, lb Fig. 8. — Broadbalk Wheat. Effect of increasing amounts of Nitrogen on the production of Wheat (Grain and Straw). Average, 51 years (1852-19u2). The figures in the labels indicate bushels of Grain and cwt. of Straw. 32 BROADBALK FIELD tion. The yield of the other three plots increases with each addition of nitrogen ; the grain increases from 23 bushels with 43 lb. of nitrogen, to 32 bushels with 86 lb. of nitrogen, and to 36 J bushels with 129 lb. of Total Produce per Acre 6000 lb— 50OO 400O 3000 Straw per Acre J b. Grain per Acre Jb Fio. 9. — Comparison of Nitrate of Soda and Ammonium-salts on Wheat. Ten years (1893-1902). All Plots receive Minerals alike. The figures in the labels indicate bushels of Grain and cwt of Straw. nitrogen ; the straw is even more affected by a free supply of nitrogen, rising from 21 J cwt. to 33 and 41 cwt. as the nitrogen is doubled and trebled. Comparative Effect of Nitrate of Soda and Ammonium-salts. Plot 6 should be compared with Plot 9, and Plot 7 with Plot 16. Plots 9 and 16 receive nitrate of soda and mineral manures, so that WHEAT 33 Plot 9 has the same manuring as Plot 6, and Plot 16 as Plot 7, except that the ammonium-salts on Plots 6 and 7 are replaced by equivalent amounts of nitrogen as nitrate of soda. The manuring of Plots 9 and 16 has, however, been changed during the progress of the experiments, so that they are only comparable with 6 and 7 since 1885. Taking a recent ten year average, as set out in the diagram. Fig. 9, it will be seen that nitrate of soda is a more effective source of nitrogen than the ammonium- Total Produce perAcre 6000 lb. — 86lb.N. after Minerals only in PreviousYear. Straw per Acre, lb Grain per Acre, lb. Fig. 10.— Comparative Eifects on Wheat of Ammonium-salts applied at different times. Averages— Plots 5, 17, and 18, 51 years (1852-1902). Plots 7 and 15, 25 years only (1878-1902). The figures in the labels indicate bushels of Grain and cwt. of Straw. C 34 BROADBALK FIELD salts; the single application yields 16 per cent, more grain and 26 per cent, more straw than the corresponding amount of ammoniuni-salts ; the double application, however, yields practically the same amount of grain, and only about 1 cwt. more straw. Effect of the Mineral Ccnstituents. The series of Plots 7, 10, 11, 12, 13, and 14 all receive the same amount of nitrogen — 86 lb., in the form of 400 lb. of ammonium-salts per acre — but differ in regard to their mineral manuring. Plot 10 receives nothing beyond the nitrogen. Plot 11 has superphosphate also, while 12, 18, and 14 receive a further addition of sulphate of soda, sulphate of potash, or sulphate of magnesia respectively, all three of which are combined to form a complete mineral manure on Plot 7. Retention of Manures hy the Soil, As a rule 100 lb. of the ammonium-salts are applied in the autumn when the seed is sown, the rest being reserved for a top-dressing in the spring. On one of the plots, however. Plot 15, the whole 400 lb. of ammonium-salts is applied in the autumn, otherwise the manuring is identical with that of Plot 7. The crop, however, on Plot 15 is on the average below that of Plot 7, showing that some loss takes place when the ammonium-salts are applied before the plant is able to utilise them. Plots 17 and 18 further illustrate the fate of ammonium-salts. These plots receive the dressing of Plot 7 — 400 lb. ammonium-salts and com- plete minerals — but the ammonium-salts and the minerals are applied in alternate years to the two plots. Thus in 1912 Plot 17 receives ammo- nium-salts but no minerals, and Plot 18 the minerals without the ammonium -salts, and the treatment is reversed in 1911 and again in 1913. The plot which in any year is receiving minerals without nitrogen derives little or no benefit from the ammonia it had the year before. The crop shows every sign of nitrogen starvation, and amounts on the average to only 14*9 bushels of grain, as compared with 14'5 bushels on Plot 5 which has received minerals without any nitrogen every year since 1852. On the Rothamsted soil, then, we may conclude that the eff'ect of sulphate of ammonia applied to a cereal crop is confined to the season of its applica- tion. In the seasons when the ammonium-salts are applied the crop is but little short of that on Plot 7, and sometimes (as in 1911) is even greater where minerals are used every year with the same amount of ammonium- salts, thus showing that the previous mineral manuring is carried forward and has an effect in seasons beyond the year of its application. BARLEY 35 HOOS FIELD Barley The experiments on the continuous growth of barley were begun in the Hoos field in 1852. The arrangement of the plots and the manures applied to each plot have practically been unchanged since, so that the plots to-day show the effects of more than sixty years' continuous growth of barley under the same treatment year after year. There are four longitudinal strips receiving different combinations of the mineral these are all crossed by four breadths receiving different nitro- manures ; Table XVII. — Experiments on Barley^ Hoos Field. Manuring of the Plots per acre per annum^ 1852 and since. riot. Abbreviated Description of Manures. Nitrogenous Manures. Mineral Manures. Is IS 1 1 It "A i II ll o Tons. Lb. Lb. Lb. Cwt. Lb. Lb. Lb. Lb. lO No Minerals and no Nitrogen ... ... ... ... ... ... ... 20 Superphosphate only, do. ... ... ... ... 3-5 ... 30 Alkali Salts only, do. ... ... ... ... 200 100 100 40 Complete Minerals, do. ... ... ... 3-5 200 100 100 ... 1 A Aramonium-salts alone . ... 200 2A Superphosphate and Amrao- niura-salts .... 200 3-5 3 A Alkali Salts and Ammonium- salts ... 200 200 100 100 4A Complete Mineralsand Ammo- nium-salts .... ... 200 ... 3-5 200 100 100 1 AA Nitrate of Soda alone . ... 275 2AA Superphosphate and Nitrate of Soda . . . . 275 3-5 3AA Alkali Salts and Nitrate of Soda 275 200 100 100 4AA Complete Minerals and Nitrate of Soda . . . . ... ... 275 3-5 200 100 100 ... 1 AAS As 1 AA and Silicate of Soda . 275 400 2AAS As 2AA and do. ... ... 275 3-5 ... ... ... 400 3 AAS As 3AA and do. ... 275 200 ido ibo 400 4 AAS As 4AA and do. 275 3-5 200 100 100 400 IC Rape Cake alone . 1000 ... ... ... ... ... ... ... 2C Superphosphate and Rape 1000 3-5 3C Alkali Salts and Rape Cake '. 1000 ... 200 100 100 ... 4C Complete Minerals and Rape Cake ..... ... 1000 ... ... 3-5 200 100 100 ... 7-1 Unmanured (after dung 20 years, 1852-1871) 7-2 Farmyard Manure . 14 ... ... ... ... ... E. — Plan of the Plots in Hoos Fidd on which Barley has been Grown since 1852. Total area of ploughed land, about 6^ acres. 1, 2, 3, and 4, of Series O, Series A, and Series C, each ^ acre. 1, 2, 3, and 4, of Series AA and A AS, each ^t acre. Area of Plots -! 1 N, 2 N, 5 O, and 5 A, each ^ acre. 6-1 and 6-2, each about f acre. J'\ and 7-2, each about I acre. The double lines indicate division paths between plot and plot. BARLEY 37 genous manures. The mineral manuring on the strips is as follows: — (1) None ; (2) Phosphoric acid only, no potash or alkali salts ; (3) Potash, magnesia, and soda, no phosphoric acid; and (4) Complete mineral manure, supplying both phosphoric acid and the alkaline salts. Each of these is combined with the four cross-dressings of nitrogenous manures Series O, no nitrogen ; Series A, ammonium-salts ; Series AA, nitrate of soda ; Series AAS as Series AA and silicate of soda in addition ; and Series C, rape cake. There are other plots, one of which received farm- yard manure for the first twenty years, but has since been unmanured. Table XVIII. — Experiments on Barley, Hoos Field. Produce of Grain and Straw per acre. Averages over 60 years (1852-1911), a?w? over 10 (1902-1911). Also Produce in 1911. Plot Abbreviated Description of Manures. Dressed Grain. Straw. 2S S 1. 1^ S 1"^ 1 < d lO 2 0 30 40 No Minerals and no Nitrogen . Superphosphate only, do. Alkali Salts only, do. . . . Complete Minerals, do. . . . Bash. 12-7 19-7 15*2 19-7 Bash. 9-3 17-6 10-1 15-9 Bush, 4-9 11-9 4-3 5-9 Cwt. 8-4 10-0 8-8 11-1 Cwt. 6-2 9-2 8-2 12-4 Cwt. 5-5 9-1 5-3 7-8 1 A 2A 3A 4A Ammonium-salts alone .... Superphosphate and Ammonium-salts Alkali Salts and do. Complete Minerals and do. 25-5 38-2 28-0 41-5 19-7 29-7 20-3 38-4 13-8 10-3 11-8 28-5 14-7 22-0 16-9 25-0 13-0 19-3 15-6 25-3 12-5 11-6 14-1 22-9 1 AA 2AA 3 AA 4AA Nitrate of Soda alone .... Superphosphate and Nitrate of Soda Alkali Salts and do. Complete Minerals and do. 29-3 43-1 30-0 42-7 23-0 38-6 21-4 37-8 16-2 26-1 12-5 28-9 17-8 26-3 19-3 27-3 16-1 26-5 16-1 26-3 17-8 24-7 14-5 23-7 1 AAS 2 AAS 3 AAS 4 AAS As Plot 1 AA and Silicate of Soda . As Plot 2 AA do. do. As Plot 3 AA do. do. As Plot 4 AA do. do. 32-8* 42 '3* 35-2* 43-6* 28-0 37-2 29-0 40-4 19-7 26-0 17-6 27-5 19-7* 26-0* 21-7* 27-7* 18-5 25-9 20-3 27-1 18-4 24-6 18-1 24-8 IC 2C 3C 4C Rape Cake alone Superphosphate and Rape Cake Alkali Salts and do. Complete Minerals and do. 38-3 40-5 36-9 40-5 33-4 35-4 33-1 38-2 27-4 28-2 21-6 25-7 22-1 23-6 22-3 24-5 20-7 22-0 21-9 24-4 20-7 20-8 18-6 20-1 7-1 7-2 Unmanured (after dung 20 years, 1852-71) Farmyard Manure 24 •8t 47-1 18-3 44-3 9-5 23-0 14-8t 29-6 12-9 31-7 10-5 24-0 48 years (1864-1911). t 40 years (1872-1911). Effect of Nitrogerwiis Manures. The effect of nitrogenous manures upon the barley crop is best seen by comparing the yields of the various Plots 4, all of which receive the same mineral manures; the diagramr ^\ft 11, slinw« tViic nr^r^^^^\r. — .•„ graphic form. 11, shows this comparison in C 2 38 HOOS FIELD Effect of Mineral Manures. The diagram, Fig. 12, shows in a graphic form the effects of the various mineral manures, the nitrogen supply being the same in all cases. The great importance of phosphoric acid to the barley crop is seen on comparing Plots 3 and 4, which only differ from one another in the omission of phosphoric acid on Plot 3. In the field the most striking Total Produce per Acre. «ooolb. Plot 10 4 0. Unmanured Minerals only. 4A. 4AA. Minerals Minerals +43lb.N. +43lb.N. sAmmonia. as Nitrate. AC. 7-2 Minerals Farmyard +49lb.N. Manure as Rape Cake. ^ Grain per Acre, lb. Straw per Acre, lb Fig. 11. — Yield in Barley (Grain and Straw) with diflferent sources of Nitrogen. Averages for 51 years (1852-1902). The figures in the labels indicate bushels of Grain and cwt. of Straw. effect is seen in the hastened maturity brought about by the phosphoric acid. By comparing Plot 2 with Plot 4 we can see the effect of omitting potash from the manure. Where nitrate of soda is used as the source of nitrogen the soda liberates sufficient potash from the soil to supply the needs of the crop, but with ammonium-salts the omission of potash has latterly begun to tell upon the yield, though it did not do so in the earlier years of the experiment. BARLEY 39 Total Produce per Acre. Mb. 5000 4-00O -3000 20OO Nitrogen only. Nitrogen and Phosphoric Acid. Grain per Acre, lb. Nitrogen Nitrogen, and PhosphoricAcid Potash. and Potash. Straw per Acre, lb. Fig. 12.— Effect of Mineral Manures on the yield of Barley (Grain and Straw). Mean of Series A, AA, and C. 51 years (1852-1902). The figures in the labels indicate bushels of Grain and cwt. of Straw. 40 HOOS FIELD Y.—Hoos Field Leguminous Plots. Season 1906. i o Co CD O^its in CO o i o CO t3 Cfc; 1904 - CX) o 2? c o Co Q) I O to s^ Q) i^ O CD CO 05 i o to ^* QJ ■§ JO O o i o ^ ^1 )z >D >C ^B >A [Total area under experiment, about 3 acres.] These crops were left for a time, then cereals were introduced, as shown in Table XIX., p. 41. HOOS FIELD 41 HOOS FIELD— LEGUMINOUS PLOTS 1848-9 ONWARDS The small plots (see Plan on page 40) represent portions of the original plots on which attempts have been made to grow leguminous plants continuously since 1848. Various combinations of mineral manures have been used up till 1898, but after the first few years very small crops have been grown, and the clovers in particular generally fail. After fallowing in 1903 to clean the plots, they were resown as before in 1904. The remainder of the area was formerly occupied by similar small plots of the same leguminous plants. These were ploughed up in 1898, and five crops of wheat were taken without manure in order to test the amount of nitrogen accumulated by the leguminous crop and left in the soil. In 1904 black tartarian oats were sown, and in the oats, lucerne, red clover, and alsike clover were sown on three strips ; a fourth strip, fallowed in 1904, was sown with vetches in October of that year, as shown in the Plan on page 40. The new plots run across the old ones at right angles. The following table shows the crop obtained in 1905 and each year since to 1912 inclusive. Table XIX.— Produce , Hoos Field Leguminous Land. Season 1906. Season 1906. Season 1907. Season 1908. Season 1909. Season 1910. Season 1911. Season 1912. Lucerne . Red Clover . Alsike Clover . Vetches . Cwt. 38-1 47-2| 36-9] 45-8 Cwt. 55-2 Cwt. 90-6 J67-5 |27-8 24-2 Cwt. 83-9 12-2 Cwt. 15-3 2-4 4-0 19-6 Cwt. 53-3 60-4 46-3 ... Cwt. 56-9 23-0 35-7 8-9 Oats Bush. 50-9 37-2 29-1 Straw Cwt. 29-5 23-5 19-2 Barley bush. 36-2 Straw cwt. 25-6 22-3 cwt. 5-6 Dates of sowing leguminous seeds :— Lucerne . 13th May 1904, and 1st June 1909. Red Clover , 13th May 1904, 10th May 1906, and 1st June 1909. Alsike Clover . 13th May 1904, 10th May 1906, and 1st June 1909. Vetches . 3rd October 1904, 5tb April 1906, 11th March 1907, SOth May 1907, 5th November 1907, 9th October 1908. Fallow 1910, 1 8th October 1910. HOOS FIELD— POTATO PLOTS Residue of Manures On ten plots potatoes were grown with various manures for 26 years (1876-1901). In 1902 the manuring was discontinued and barley sown. Table XX. shows the yields obtained. O. — Plan of the Plots in Hoos Field on which Potatoes were grown without Manure, and with various Manures. 26 years, 1876-1901. In 1902 and 1903 Barley, and in 1904 Oats, were sown, without manure, to determine the duration of the residues of the previous manuring In 1905 and each year to 1911 Barley was sown, and in 1912 Oats, on Plots 1-4 without manure. Plots 5-10 sown with Leguminous seeds each year to 1911, and Oats in 1912. — ■ — , (0. A B L c D k. k i, 9 E F 7 G 6 6 1 — — ' Total area of ploughed land, about 2^^ acres. Area of each plot, \ acre. The double lines indicate division paths between plot and plot. I o i ^- Is CO I "^ i if ^ I 2 CD 5 CM c3 11 .00 5^ r-t t>. OS r-t »-i 1 31 Lb. 2068 2085 2905 3086 2099 i •ajBio pessejQ 00 (N •-• C^ 00 in OS •g 9 o t- 00 00 n 32 i-t o t^ I-H O P4 62 ^ OS oo 00 t>. «o _^ « OT OS i ;,« O rH rH -* -* ^ •ui»JO p9SS9Ja 1- cq p 4f* op «p o CO I-t t-l n l«lox O* OS t- 1-t f-( ^ >p »o to -Jjt p ^ «o CO i) (» ,Ih O «© «0 O rH 00 r-t I-t CO UIBJO pessejQ 3«0 I-H I-t i-i i-i 00 »o 1-1 CO 1 ^ (?? ■<* 00 rH rH ;S2 i S i5 2 9> •ai«JO pessojo; SOS T-i il Wox .CO to I-I f> it ^ o o i) o O CO (M lO (N ■* p Tjt pessaiQ IS 00 PQ t^ I-I I-t r-t It Z.83 9.^9 4i "* ^T^'^rsT ?= b ko CO oo'9 5 g fj oo 00 -9»i«''§ "C^-^Tjll^OO ^0O(NW.t>. O 0-69 O rH oo T»t r^ cot^ CO •uiwo pessaiQ do> o \a (1 X>0O h5CO o rH I-I h-* m oo" . : •uj«JO pessoaa IS ^» CO CO a •MWfJg «o O 00 o 00 oo o ■* t^ <0 OS CO o rH CI «0 CO rH rH rH i-H •attiJO passaaa IS cq(N r-i IS 5 7^ ^ OS CO ^• S §3 ^ ^ ^ O is §1 ^s r^ ■^ to t^ oo CO CO oo rH rj< OO O ^ ,-t CO -* OS O 0» CD t^ 00 f^ rH r-l 00 00 pasBwa OS Oi I-H t^ «>- 00 (N rH t^ = •3 tgc^ «•«■ 9* OQ •2 3 5 .a Q* A fc^ a> D» 3 1 03 1 3 •«n ^ 3 2 1" .3 '$ I-t a 1 3 r- 44 HOOS FIELD HOOS FIELD Inoculation of Leguminous Plants Since the land on which potatoes had been formerly grown (see Plan on page 42) is known to have carried no leguminous crop for the last fifty years, it was decided to use those plots which no longer showed much residue of the manures previously applied, i.e.. Plots 5-10, for testing the comparative effects of different media for inoculating leguminous plants with their appropriate bacteria. In 1905, therefore. Plots 6, 8, and 10 were divided transversely into four plots ; on A, soil inoculated with Hiltner's preparation from Munich; on B, soil inoculated with Moore's preparation from the United States ; on C, soil from a field which had carried red clover in 1904, were sown on 7th April ; D being left uninoculated. Red clover seed was sown on 15th May over the whole area, and was continued each year to 1911 inclusive; in 1912 a crop of oats was taken. See yield in Table XX. Plots 5, 7, and 9 were similarly divided into three plots and sown with cow peas ( Vigna catjang), a leguminous plant quite new to this land. On E, the seed was inoculated with Moore's medium just before sowing; on F, soil obtained from an old cow pea field in the United States was spread; and G was not inoculated. The cow peas were sown on 16th May, but failed to give a satisfactory plant, and were ploughed up. The plots were sown with red clover in 1906, as part of a further trial of the continuous growth of clover. This continued to 1911 inclusive; in 1912 oats were grown on the plots. For results, see Table XX. Table XXl.—Fxperiments on Wheat, alternated ivith Fallow, without Manure {Hoos Field), 62 years (1851-1912) ; and grown continuously without Manure {Broadbalk Field), 62 years (1851-1912). Average produce of Grain per acre, and Produce last two years, 1911 and 1912. Dressed Grain. Wheat after Fallow each year (Hoos Field). Wheat after Wheat each year (Broadbalk). After Fallow + or - after Wheat. Averages— Produce after Fallow, reckoned at the yield per Acre of the half in Crop each year. 6 years (1851-55) . 10 „ (1856-65) . 10 „ (1866-75) . 10 „ (1876-85) . 10 „ (1886-95) . 10 „ (1896-1905) 60 „ (1856-1905) 67 „ (1851-1912) 1911 1912 Bushels. 19-2 26-1 13-5 14-8 15-1 14-3 ]6-7 16-0 17-0 4-2 Bushels. 14-7 15-9 11-9 11-3 12-1 11-7 12-5 12-2 12-5 4-6 Bushels. + 4-5 + 10-2 + 1-6 + 3-5 + 3-0 + 2-6 + 4-2 + 3-8 + 4-5 - 0-3 WHEAT AFTER FALLOW 45 HOOS FIELD Wheat after Fallow The two half-acre plots in Hoos field are never manured, but every year one carries a wheat crop and the other is given a bare summer fallow, the treatment alternating, so that every year one plot is carrying a wheat crop following a bare fallow. By comparing the results obtained with the yield of the unmanured plot growing wheat continuously, the benefit of the bare fallow can be estimated. (See Table XXI.) LITTLE HOOS FIELD Residual Value of Manures The object of the experiments in this field is to test the residual value of certain typical manures, i.e., the value of the residues left in the soil after one or more crops have been grown since the time of their applica- tion. To eliminate the effect of season, the result yielded by the residue is in all cases compared with that of a new application of the same manure, as well as with a continuously unmanured check plot. The ordinary dung is made by feeding beasts with hay and roots only, the beasts making the cake-fed dung alongside receive also an ordinary allowance of linseed and cotton cake. The two lots of dung are then laid up in heaps for a short time, and weighed out immediately before applying. Table XXII. — General Dressings of Mineral Manure on Series A to Bj and of NitrogeThotLS Dressings on Series F to II. (Quantities per acre.) Series A to E. Series P, G, H. 1904 3 cwt. Superphosphate. 1904 1 cwt. Sulphate Ammonia. 1905 1905 1 cwt. Sulphate Ammonia. 1906 3 cwt. Sulphate Potash. 1906 2 cwt. Sulphate Ammonia. 3 cwt. Sulphate Potash. 1907 3 cwt. Superphosphate. 1907 1 cwt. Sulphate Ammonia. 1908 3 cwt. Superphosphate. 1908 1 cwt. Sulphate Ammonia. 1909 3 cwt. Superphosphate. 1909 1 cwt. Sulphate Ammonia. 1910 ... 1910 1 cwt. Sulphate Ammonia. 1911 3 cwt. Superphosphate. 200 lb. Sulphate Potash. 1911 1 cwt. Sulphate Ammonia. 200 lb. Sulphate Potash. 1912 ... 1912 1 cwt. Nitrate Soda. B.— Little Hoos Field. Plan of Rotation Plots arranged to test the Residual Value of various Manures— one, ttvo, three, and four years after their application. 9 CO O o B c (2) Dung (ore// nary J 16 tons per acre /907, )L '15 Dung (Cake-fed) /6 tons per acre /907, 'II, V5 B Shoddy I ton per acre 1307, 'II, 75 H 5 Guano S cwt per acre 1907, 7/, 75 Superphosphate Sup 600 lb. per acre /907, II, V5 4 Dung (ordinary) IStons per acre 1906. 10 '1^ Dung (Cal> . „ TS +3"* and. Plot. Manuring. jl |S 1- 1- "go 0 Tons. Lb. Tons. Lb. Tons. Lb. Lb. Tons. Bush. Al Unraanured. 10-3 2323 17-1 3650 14-0 3792 2270 11-6 19-4 2 Dung, ordinary (1904, '8, M2) 181 4649 18-2 4673 191 5128 2572 13-9 84-8 3 (1905 & '9). 8-8 8501 17-5 5393 14-5 5544 2681 14-1 26-9 4 (1906 & '10) 8-8 2269 182 5471 15-5 4057 2406 12-5 29-2 5 (1907 & '11) 9-8 2402 14-9 6908 17-3 4581 2358 158 26-8 Bl Dung, cake-fed (1904, '8, '12) 15-7 4177 19-4 4319 22 4 5362 2386 14-1 85-6 2 Unraanured .... 10-0 2417 16-2 4025 14-3 3862 2261 12-0 21-8 3 Dung, cake-fed (1905 & '9) . „ (1906 & '10) 9-5 5580 18-5 5497 14-2 6641 2921 14-2 29-4 4 11-4 2772 25-6 6489 16-9 4400 8502 14-4 26-5 5 „ (1907 & '11) 9-4 2649 14-4 9407 190 4298 2369 171 31-4 CI Shoddy (1904, '8, & '12) . 14-7 3656 21-0 4667 19-7 3969 2295 11-4 28-4 2 (1905 & '9) . 11-1 4868 23-6 4550 16-3 4568 2387 11-6 26-1 3 Unraanured .... 10-6 2.'i88 17-7 4334 15-1 3850 2561 11-7 24-2 4 Shoddy (19(6 & '10) . 10-7 2512 24-2 6231 19-1 4466 8461 140 30-4 5 „ (1907 & '11) . 10-3 2615 16-9 7495 22-2 5448 2560 14-7 29-8 Dl Guano (1904, '8, &*1 2) 14-6 2550 20-1 4056 20-9 3608 1742 10-5 28-8 2 „ (1905 & '9) 11-0 5176 19-7 4165 15-3 6884 2114 11-5 24-1 3 „ (i906&'10) . 10-9 2857 25-6 4846 15-9 4053 8892 iri 22-5 4 Unraanured 10-6 2985 18-7 4618 17-4 4510 2739 11-8 26-9 5 Guano(1907&'ll) . 10-6 2680 17-4 7875 15-7 4014 2374 14-2 26-3 El Rape Cake (1904, '8, & '12) . 141 2674 17-8 3887 19-7 3750 2180 10-7 27-7 2 (1905 & '9). (1906 & '10) 11-2 4185 17-9 4326 15-1 5208 2242 11-7 22-3 3 9-5 2645 22-7 4584 14-5 3866 8486 11-5 22-2 4 (1907 & '11) 10-5 27M4 19-4 6619 15-2 4661 2516 14-5 25-1 5 Unraanured 10-8 2769 19-5 4527 14-7 4155 2784 12-7 21-1 Fl Unraanured .... 11-7 3132 22-9 4749 14-1 4814 3166 8-7 31-6 2 Superphosphate (1904, '8, '12) 12-2 3025 23-2 5064 16-9 4726 3223 10-9 88-4 3 (190.^. & '9) \0'1 8949 v3-6 49.=i6 14-tJ 4978 2922 11-7 31-9 4 (1906 & '10) 9-7 3913 24 1 f.419 16-0 5280 2682 12-8 34-9 5 (1907 & '11) 9-7 4221 23-6 5698 16-4 5641 3190 14-2 35-4 Gl Bone-Meal(1904, '8, &'12). 12-9 3176 23-1 5203 16-7 4445 3345 9-9 82-8 2 (1905 & '9) 10 1 8636 22-1 5821 14 3 4922 36.=.7 9-9 32 7 3 Unraanured. 10-2 3495 20-6 5491 12-7 4247 3701 9-2 29-0 4 Bone-Meal(1906&'10) 9-9 3450 22-6 6043 14-2 4711 8268 10-5 31-8 5 (1907 & '11) . 9-2 3525 22-1 6276 19-9 5285 3512 12-6 34-4 HI BasicSlag(1904, '8, '12) . 11-8 4400 20-5 6285 18-8 4182 3564 11-5 85-7 2 (li^Oo & '9) . 10-4 4002 21-3 5930 13-6 4580 3.^96 12-0 33-7 3 (1906 ^'10) 9-4 3662 21-4 .^860 13-6 4431 8948 12-5 29-1 4 (1907 & '11) 9-1 3624 17-0 5816 14-4 3860 3804 120 32 5 5 Unraanured 8-6 3293 17-4 5933 11-4 4511 4005 10-5 30-1 The yields on the plots to which the manure was applied in any given year are printed in heavier type. * Dressed Grain only . The Incorporated Society for Extending the Rothamsted Experiments in Agricultural Science Chairman His Grace THE DUKE OF DEVONSHIRE, P.O. J. F. MASON, Esq., M.P. (Vice-Chairman). Dr HUGO MtJLLER, F.R.S. (Treasurer). Prof. H. E. ARMSTRONG, LL.D., F.R.S. R. H. BIFFEN, Esq., M.A. Dr H. T. BROWN, F.R.S. J. B. FARMER, Esq., M.A., F.R.S. ROBERT MOND, Esq. The Most Hon. The MARQUESS OF LINCOLN- SHIRE, K.G., P.O. Right Hon. Sir JOHN BRUNNER, Bart. P.O. Captain J. A. MORISON. Sir W. S. PRIDEAUX. Dr A.B. RENDLE, M.A., F.R.S. Sir J. H. THOROLD, Bart. Dr J. A. VOELCKER, M.A. J. MARTIN WHITE, Esq. E. J. RUSSELL, D.Sc. (Hon. Secretary). ^T^HIS Society collects Donations and Annual Subscriptions for •*" the purpose of extending the Rothamsted Experiments. The donations enable the Committee to qualify for Capital Grants from the Development Fund, while the subscriptions form a valuable contingency fund for meeting unforeseen expenditure arising out of new work without the necessity for curtailing old work. Subscriptions and donations should be sent to the Secretary, Rothamsted Experimental'. Station, Harpenden. PHINTED BY OLIVBB ASD BOTO, BJDINBCBGH. jT^Vf'' ms^M^ For a General Account of the whole of the Experimental Work at Rothamsted, see The Book of the Rothamsted Experiments By A. D. HALL, M.A., F.R.S. Published by JOHN MURRAY, London, 1905 10/6 net