Respiration characteristics of cotton soil under irrigation and fertilization measures in arid region

To discuss the soil respiration rate and its relationship with soil temperature and moisture, two different irrigation methods including drip irrigation and flood irrigation and four fertilizer treatments including organic manure(OM), N P K fertilizer(NPK), combined application of NPK fertilizer and organic manure(NPK+OM), and no fertilization(CK) were arranged during cotton growth period in Xinjiang oasis. Soil respiration rate, soil temperature and soil moisture were measured and analyzed under different irrigation methods and fertilizer treatments. The results showed that soil respiration rate of cotton field exhibited a significant seasonal variation feature, and soil respiration rate reached a peak in mid-July and reduced to the minimum in mid-October after cotton harvest; The diurnal variations of soil respiration rate showed a single peak curve, and the highest peak of full flowering stage appeared at 15:00-17:00 and full bolling stage appeared at 15:00 and the minimum value appeared at 04:00. Soil respiration rate under drip irrigation was larger than that under flood irrigation, and the soil respiration rate with (NPK+OM) treatment was the highest, and then followed by OM, CK and NPK among the fertilizer treatments. The average temperature sensitivities of soil respiration under drip and flood irrigation were 2.03 and 2.43, respectively. The Q10 value under drip irrigation was larger than that under flood irrigation. Under different irrigation and fertilizer measures, compound equation could predicted soil respiration rate, and the coefficient of determination was 0.64-0.72. Considering the effects of soil temperature and soil moisture content on soil respiration rate could improve the accuracy of the research into regional soil respiration rate.