Pre-seeding tillage of long-term no-till soil may alter soil quality by changing some properties, but the magnitude of change depends on soil type and climatic conditions. Effects of short-term (2 or 3 years) tillage (hereafter called reverse tillage [RT]) of land previously under long-term no-till (NT, 29 or 30 years), with straw management (straw removed [SRem] and straw retained [SRet]) and ...

The relationships between N fertilizer rate, yield, and NO3 leaching need to be quantified to develop soil and crop management practices that are economically and environmentally sustainable. From 1996 through 1999, we measured yield and NO3 loss from a subsurface drained field in central Iowa at three N fertilizer rates: a low (L) rate of 67 kg ha(-1) in 1996 and 57 kg ha(-1) in 1998, a medium...

plant growth regulators (pgrs) are widely used for lodging control in winter wheat (triticum aestivum l.) grown at high n rates. although the introduction of semi-dwarf wheat cultivars had largely solved the problem of lodging, evidence was already accumu-lating that the timely application of a growth retardant such as chlormequat (ccc) or ethephon could increase the grain yield of wheat, by th...

Current biofuel feedstock crops such as corn lead to large environmental losses of N through nitrate leaching and NO emissions; second-generation cellulosic crops have the potential to reduce these N losses. We measured N losses and cycling in establishing miscanthus (), switchgrass ( L. fertilized with 56 kg N ha yr), and mixed prairie, along with a corn ( L.)-corn-soybean [ (L.) Merr.] rotati...

This study was conducted to measure the effects of slurry application method, swine growth stage, and flow rate on runoff nutrient transport. Swine slurry was obtained from production units containing grower pigs, finisher pigs, or sows and gilts. The swine slurry was applied using broadcast, disk, or injection methods at a rate required to meet annual nitrogen requirements for corn. Three 30 m...

abstract- declining land productivity associated with decreasing soil organic carbon and nutrients is a significant issue in monoculture production. the field experiment with different rates of fertilizer systems (60 kg ha-1 n + 100 kg ha-1 p, 300 kg ha-1 bio-organic (organic fertilizer), 3 kg ha-1 bioumik (biofertilizer), 30 kg ha-1  n + 50 kg ha-1 p + 150 kg ha-1 bio-organic fertilizer and 30...

Maize (Zea mays L.) production requires large amounts of nitrogen (N) thatdirectly affect production cost. Poultry litter can be used as an alternative source ofN. To optimize its use, poultry litter requires technical and economic feasibilityanalyses. Crop simulation models have proven to be efficient tools to support thistype of research. The objectives of this study were to determine yield a...

a field study was conducted at abourehan research farm of tehranuniversityin 2009 to find out the effects of slow releasing nitrogen from pellet fertilizer of nitrogen and manure on grain yield and some physiological characteristics of corn (single cross 704). the factorial design of the study comprised of randomized complete block with three replications. factors this experiment involved: firs...