energy method of evaluation is widely employed in analyzing problems associated with sustainable agriculture. in this study, energy ratio (er) of dryland wheat for three regions of eghlid township was quantified. the total cropping area of eghlid is nearly 8282 hectares comprised of: khosrowshirin (5000 ha), sedeh (1682 ha) and dezhkord (1600 ha). the corresponding values of wheat yield in thes...

Accurate simulation of agricultural management effects on N loss in tile drainage is vitally important for understanding hypoxia in the Gulf of Mexico. An experimental study was initiated in 1978 at Nashua, Iowa of the USA to study long-term effects of tillage, crop rotation, and N management practices on subsurface drainage flow and associated N losses. The Root Zone Water Quality Model (RZWQM...

Because the adoption of conservation tillage requires long-term evaluation, the effect of tillage and residue management on corn (Zea mays L.) grain and stover yields was studied for 13 seasons in east central Minnesota. Three primary tillage methods (no-till (NT), fall chisel plow (CH), fall moldboard plow (MB)) and two residue management schemes (residue removal versus residue returned) were ...

Soil organic carbon (SOC) and nitrogen (N) are directly influenced by tillage, residue return and N fertilization management practices. Soil samples for SOC and N analyses, obtained from a 23-year field experiment, provided an assessment of nearequilibrium SOC and N conditions. Crops included corn (Zea mays L.) and soybean [Glycine max L. (Merrill)]. Treatments of conventional and conservation ...

The objective of this study was to explore if more crop-specific plant growth modules can improve simulations of crop yields, and N in tile flow under different management practices compared with a generic plant growth module. We calibrated and evaluated the Root Zone Water Quality Model (RZWQM) with the Decision Support for Agrotechnology Transfer (DSSAT v3.5) plant growth modules (RZWQM–DSSAT...

The adoption of no tillage (NT) in crop production has been encouraged primarily due to its more significant benefits to the environment compared with other conservation tillage systems. There are nevertheless concerns about NT corn (Zea mays L.) performance from both shortand long-term perspectives. This study was conducted near Burlington, Nashua, Newell, Sutherland, and Crawfordsville in Iow...

NT will reduce soybean grain yields and economic returns, particularly during the first few years of adoption. Farmers have been encouraged to adopt no-tillage (NT) because Soybean grain yield response to NT systems depends of its positive environmental effects compared with other conservation tillage systems. Nevertheless, poor crop performance under NT manmainly upon soil drainage and previou...

Kucey and Schaalje, 1986; Reeves et al., 1993; Randall et al., 1997; Torbert et al., 2001). Tillage and N management systems can have a significant effect Many soil and water quality problems are associated on N use by corn (Zea mays L.) and nitrate (NO3–N) movement with conventional tillage, along with other problems that through the soil profile. Potential water quality and NO3–N loss probaff...