BURNING OF PASTURES.

New Zealand Herald, Volume LXII, Issue 18951, 24 February 1925, Page 14

BURNING OF PASTURES.

EXPERIMENTS AND RESULTS. ! NO HARMFUL EFFECTS. Experiments were made on a 1500 aero tract of pasture land in Kansas at an altitude of 1200 ft. to 1400 ft. which was too hilly for cultivation, to demonstrate clearly 'the actual effect of burning on v(.'gelation and to disprove the controversial opinions that it encourages weed growtli and decreases the quantity of beneficial green feed. Areas were burned earlv each year and records were made with thermographs ami quadrat chartiugs. The number of plants of each species of grasses, sedges and weeds, the temperature of the soil, the time at wh'ch growth began in the spring, and the yield of forage, was ascertained in each case. The results arc classified as follows: (1) Effect of burning on grasses.—The total number of grasses was not decreased—there was, however, during 4 years, a decrease in the number of sedges compared with an increase, on the unhurried plot. There was also a change in the general constitution of the experimental areas. Big bluestem (Andropogon furcalus) and Poa pratensis behaved as the sedges, but A. scoparius, on the contrary, increased on the burned, arid decreased on the unburned plots, and Bouteloua curtipenduia decreased on both plots. (2) Effect on weeds. —The first year of experiment both plots were practically free from weeds.—The second year they were prevalent and from then onwards there was a decrease each year on the burned plot and an increase on the control plot. (3) Effect on soil temperatures. —The object was to ascertain if burning results in a warmer soil early in the spring, and if so, whether this difference could be correlated with the growth of vegetation. Results indicate that mean maximum soil temperatures at a depth of lin. averaged 12.1dcg. F. higher on the burned plot, and the mean minimum temperature 4.ldeg. F. higher. At a depth ot 3in. the maximum and minimum temperatures were 3.6deg. and 4.2 d eg. lr.gher, respectively, on the burned plot. This explains why growth starts earlier when old vegetation has been removed by burning. (4) Effect on yield of hay.-—This was slightly higher on the unburned are* but varied with seasons. The author considers these results to be sufficient evidence as to the harmless effect of burning but advises that experiments should be made on a wider scale i under varying conditions, with different tvpes of vegetation and covering a longer period, before final conclusions can lie drawn.