CONTRIBUTIONS FROM THE WISLEY LABORATORY. 179 
soon showed a superiority over the autumn section, and this became 
continually more marked as growth progressed. 
The crop was thinned to half distance on June 7 and 8, and to 
10 inches between plants on June 16. The second thinnings from 
each plot were weighed, and the weights (Table II.) give some idea 
of the relative sizes of the crops at this stage. 
The crop was harvested in the third week of July. 
At intervals throughout the experiment soil samples were taken 
and analysed for moisture, organic matter and nitrates, and counts 
of bacterial numbers were made. The green crops on each plot 
were sampled for yield and analysis before digging in, the yield being 
estimated from the weight of cleaned fresh tops and roots from an 
accurately measured representative square yard. The turnip crop 
on each plot was weighed both as whole plants and as roots alone. 
The produce from each of the ten rows on the plot was separately 
weighed, all plants within one foot of the ends of rows being excluded ; 
while, in computing the true yield, the two outer rows were also 
excluded. The " edge effect " was thus eliminated. 
Results. 
The yields of green crops in each section of the experiment are 
shown in Tables III. and IV. 
Table III. 
Autumn Section. 
Yields of Green Crops at Time of Digging in. 
Sown August 20-21, 1919. Dug in December 12-14, 1919. 
Fresh Tops. 
Ash-free dry matter 
(roots included). 
Crop. 
Plot. 
Tons per acre . 
Mean. 
Cwt. per acre. Mean. 
Mustard 
1 
12 
13 
4*5 
6-7 
{ 5'6 
21-4 
9 
Turnip 
f 
8 
17 
3-6 
4*7 
1 4*2 
18-8 
Oats . 
i 
1 
5 
16 
3-6 
{ 3-6 
16-0 
Vetch. 
1 
1 
10 
23 
4-5 
4-0 
14-9 
Rape . 
\ 
9 
20 
5-6 
2-8 
{ 4"2 
I4-7 
Rye . 
j 
i 
4 
21 
2-9 
j e-g 
ii*9 
Crimson Clover . 
J 
( 
6 
19 
i"7 
{ 1 '7 
5*7 
Red Clover . 
f 
1 
3 
22 
0-4 
{ o*4 
2-9 
Black Medick 
I 
1 
2 
15 
0*5 
1 °'5 
2*5 
Lupine 
i 
1 
7 
18 
0*4 
{ 0-4 
i*9 
Control (Weeds) . 
1 
( (inch) I 
{ roots) j 
2*2 
) 
