effects of different cotton tillage methods on n2o and nh3 emissions in a cotton-wheat rotation

Conventional tillage methods result in resource waste and the release of greenhouse gases into the environment. an experiment with a randomized complete block design and three treatments in four replications was conducted at darab agricultural research station for five years to determine the effects of different tillage methods on nitrous oxide (n2o) and ammonia (nh3) emissions in cotton-wheat rotation. direct farming (no tillage), low tillage, and conventional wheat-cotton tillage (control) were used as treatments. following wheat harvesting in the direct and low tillage treatments, 30% (weight) of wheat residues were dispersed on the field. within two years, n2o and nh3 emissions from the cotton-wheat field were estimated using the dndc 9.5 model. data from the first three years of the study was used to validate the model. the results of model validation revealed that the model performed well in simulating the soil environment as well as n2o and nh3 emissions. the simulation results revealed that the highest and lowest n2o emission rates occurred in conventional and no-tillage treatments, with a significant difference. after five years of experimentation, average annual n2o emissions were 4.40, 2.80, and 2.14 kg n ha-1 y-1 for conventional, low, and no-tillage treatments, respectively. according to the simulation results, peak nh3 emission from soil occurred on the fifth day after fertilization in all three treatments. the overall findings of this study indicated that the use of no-tillage methods is more advantageous than other cotton culture treatments in cotton-wheat rotation under similar conditions as in the current study.