ro 
OF SOUTH CAROLINA. 245 
gen and oxygen are also greatly increased, and in the proportion in which they enter into the com- 
position of water. The nitrogen, it is plain, was derived from the manure alone, for the slight dif- 
ference presented in the table must be set down to the errors unavoidable in experiments in a large way. 
Let us now examine the experiments of M. Crudd, a distinguished agriculturist, on the culture of 
green crops. 
Lucern was cultivated for five successive years, followed by a crop of wheat manured with 44,000 
kilogrammes of manure per hectare, put on at the commencement. 
Plants. Produce dry. Contents in Nitro. 
Lucern, Ist year,.....-_- - 3.060) kilos.-2 =. =s= 79 kilos. 
Be ZAG ht ee es NOOEO SE 7 ooo eas eps 
. ¢ SIG, (Seer see AUN CS AILS. Soak aoe 
i ra es ea LOOSB Mee 2 =--2525 23h $ 
ie 1 S000 Se a ee 188 “ 
Wiest, “Oth! 2 s== =~ WCU wot ont ia 31. « 
Siw 22-224 ee ee SOTGPRG Ve ate eeys 12 
SITOUAME Ole NIMROD Olsen ere ae es er oe LOGS: 
Amount of Nitrogen in manure employed,-------- 224 * 
Gann Nitrogen se 854 « 
This illustrates most admirably the value of ploughing in green crops, and taken in connexion 
with the preceeding one,the sort of crops that should be thus treated. Even the roots of such crops, 
that remain in the soil, must to some extent mitigate the exhausting effects of grain crops, on the 
nitrogenised ingredients in the soil. 
Of course where farm-yard manure, which, as we have seen, contains all that plants require, exists 
in sufficient quantity, there will be no necessity for any rotation of crops. This is also true where 
the soil is of extraordinary fertility, such as rich bottom lands and those of prairies, where the same crop 
has been raised in succession, for twenty years or more. Many of the rice plantations present also 
good examples of this sort, with the exception, that irrigation supplies much that is taken off by the 
crop, nor can I conceive, otherwise, how they could bear the enormous drain of 40 to 70 bushels of 
rice per acre, when in many cases even the straw is not returned to the soil. 
The substitution of root crops for grasses is considered in Europe among the capital improvements 
in husbandry. The following compiled by Dr. Kane, showing the actual nutritive material derived 
from an acre of land by various crops, may have some interest. 
Crop. Weight Starch §- Sugar. Gluten. Oil. Total. 
Wheat? - <2 = 1500 Ibs.---- 825 Ibs.--- 185 Ibs..- -45 Tbs.- 1055 Ibs. 
Oatssse een. set WOOF eS SSS Sopa a0 a es 
Peas.so- a: 8eh A = L600) Sis Sele ee ero SO 32.45 1 Woes: t 
Potatoes,._...--_ .- Sitons. - 3425). _ 604," ~ 45.% 4076,“ 
Turnips,-.---.--- 20 * ___.4500 © _.. 550“ | « _5040 « 
Oarrots;4- 2253554 20) 2 See OUD PEM IZORS =2200F" 269201 
Meadow hay,----. 14 _---1360.%. _<. 240)" 5190 .21720),« 
Clover hay,..-.--- Me pasa OOO ES yee An Oana SO ie 240i 
Or Drainine. 
There are no agricultural improvements more intimately connected with geological science than 
drainage operations, and where conducted upon an extended scale, a knowledge of geological struc- 
ture is absolutely necessary to entire success. 
