. Basic slags and rock phosphates . After the 15th September (which was the last date on which thenitrate content of the two pots was similar) until the 22nd the weatherwas wet, 3-19 inches of rain falling between the 15th and 22ndinclusive. The drains from both pots ran freely, but unfortunatelythe drainage water was not collected. From the 22nd to the 27ththe weather was dry and hot, no rain falling, and on the 27th whenthe pots were sampled the slag pot contained 2632 parts per miUionof nitrate and the untreated pot 10-64 parts. The relative nitratecontent of the two pots was therefore simi
. Basic slags and rock phosphates . After the 15th September (which was the last date on which thenitrate content of the two pots was similar) until the 22nd the weatherwas wet, 3-19 inches of rain falling between the 15th and 22ndinclusive. The drains from both pots ran freely, but unfortunatelythe drainage water was not collected. From the 22nd to the 27ththe weather was dry and hot, no rain falling, and on the 27th whenthe pots were sampled the slag pot contained 2632 parts per miUionof nitrate and the untreated pot 10-64 parts. The relative nitratecontent of the two pots was therefore similar to what it had beenup to August 11th. It is difficult to account for the curious results obtained duringthe period August 11th to September 15th. It may be that under 6 82 EFFECT OF PHOSPHATES the cKmatic conditions then prevailing the untreated soil at MartinsHearne is capable of yielding sufficient phosphate to enable nitrifica-tion to take place at a much more rapid rate than at any other timeduring the season. 8r3z. Fig. 19. Nitrate content of the soil on the Untreated and the Basic Slag Plots at Great Mulgraves, Horndon. Soil London clay. Season 1920. Untreated Plot Basic Slag Plot . Moisture Content 2-8 ?•«•- 2-4- Z-2 - IS1-6I4/■21-0 •8•6•4■2 s. ft A ; \ >-*t •y».« I ♦«♦ ■ ^•>^ ■ -—I fS S 19 3 17 3i /A za /£ Z6 3 23 March April May June July August 6 20 Sept Fig. 20. Rainfall at Great Mulgraves, Horndon. Season 1920. If, as is postulated here, it is correct, in view of these results,to assume that the main eJffect of phosphates on the production ofnitrate in soils well stored with nitrogenous organic matter is due totheir action on the nitrifying organisms, it is possible to explain thelarge increase in the hay crop obtained on the treated plots at ON ACCUMULATION OF NITRATES 83 Lambourne End in 1919. The various phosphates were not sownuntil January, 1919, and although clover was absent from aU theplots throughout the sea
Size: 2089px × 1196px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookidbasicslagsro, bookyear1922
