Feb. 24,1923 
Effect of Burning on Vegetation in Kansas Pastures 633 
VEGETATIVE COVER 
The principal grasses are big bluestem ( Andropogon furcatus Muhl.), 
little bluestem (. Andropogon scopariusMiQkx.), side oats grams ( Bouteloua 
curtipendula (Michx.) Torr.), and Kentucky bluegrass ( Poa pratensis L-)- 
Grasses of lesser importance are blue grama {Bouteloua gracilis H. B. K.), 
hairy grama {Bouteloua hirsuta Lag.), sand drop seed {Sprorobolus cryp- 
tandrus (Torr.) Gray) f switch grass {Panicum virgatum L.)> and Indian 
grass {Sorghastrum nutans (L.) Nash). Common weeds are annual rag¬ 
weed {Ambrosia artemisifolia L.), perennial ragweed {Ammbrosia psilo- 
stachya D. C.), prairie sage {Artemesia gnaphaloides Nutt.), prairie rag¬ 
wort {Senecio plattensis Nutt.), dwarf fleabane {Erigeron divaricatus 
Michx.), snow-on-the-mountain {Euphorbia marginata Pursh.), and others 
of lesser importance. There is considerable wolfberry {Symphoricarpos 
occidentals Hook.) on some of the overgrazed pastures. Two sedges, 
Car ex pennsylvanica Lamarck and Carex meadii Dewey, are common 
over the entire region. 
EXPERIMENTAL METHODS 
The experiments were planned to obtain data on the following points: 
1. The effect of burning on the temperature of the soil during the early 
growing season (March 15 to June 10) at depths of 1 and 3 inches below 
the surface. 
2. The effect of burning on grasses. 
3. The effect of burning on weeds. 
4. The effect of burning on the yield. 
The experiments were conducted over an area 75 by 150 feet on a ridge 
top with a slight southern slope. The area was divided into two sections. 
One of these, called section A, was burned as early each year as conditions 
would permit and the other, section B, was never burned. 
Section A (PI. 1, A) was burned March 23, 1918, March 13, 1919, April 
2, 1920, and April 7, 1921, the variations in dates being due to seasonal 
conditions: The burning was usually conducted shortly after a rain in 
order to avoid possible injury to the roots and also to afford better con¬ 
trol of the fire. 
The number of plants of each species of grasses, sedges, and weeds, the 
temperature of the soil, the time at which growth began in the spring 
each year, and* the yield of forage was determined for each area. The 
yields were generally determined in September of each year. The 
accumulated growth was cut and removed from the plots (PI. 1, B) 
immediately after. It was planned to leave as much material as is usually 
left by livestock in order to allow the plots to remain in a condition com¬ 
parable to a grazed area, although it might have been better to have 
turned in a few head of livestock. However, this would have disturbed 
the permanently staked quadrats and probably would have interfered 
with the main purpose of the experiments. 
It was originally planned to take soil samples on each plot at regular 
intervals, but this could not be done because of the rocky soil of the area. 
determining the temperature 
The four instruments used for obtaining soil temperatures were 
Columbia recording thermographs fitted with soil bulbs. Two were on 
the plot which was burned each year; one recorded temperatures at 1 
