Long term effects of wheat straw incorporation compared with burning on wheat yield and soil properties

Abstract

Two manipulations of wheat straw, burning and soil incorporation, were studied to determine the long-term effects on winter wheat (Triticum aestivum L.) yields and soil properties. The experiment was carried out on a basic calcareous soil of the semiarid Central Region of Spain, and initiated in 1979. Burning versus not burning wheat stubble was examined at three N levels on sowing time and top fertilization; 0, 28 and 56 kg ha-1 and 0, 50 and 100 kg ha-1 respectively, over 12 years. A basic inorganic fertilizer of P and K was also applied in all treatments. Stubble burning had no effect on grain yield and on grain N uptake in any of the 12 years. Significant difference between both treatments were not found. Nitrogen fertilization increased grain yield and N grain uptake.Long term burning reduced the oxidable organic matter, but this decrease was not significative. Total and inorganic N in soil did not significantly changed in the plot with burning straw as compared to the plots with straw incorporated. Soil samples from straw-incorporated treatments showed a light decrease in soil pH, and plots where straw was burnt the cation exchangeable capacity (CEC), decreased significantly (p < 0.05), in all treatments.