Nitrogen (N) is an essential and often limiting nutrient to plant growth. Maize grain yields are highly responsive to supplemental N, leading to annual application of an estimated 10 million metric tons of N fertilizer to the maize crop worldwide (FAO 2004). Nearly all cultivated maize in developed countries receives some form of N fertilizer and N use is increasing in developing countries, whe...

Two field experiments were conducted to know the effect of different doses of nitrogen fertilizer on the growth, botanical parameters and yield of maize and jumbo fodder cultivated with cowpea as inter crop and evaluation of silage. The experimental plots for Jumbo with cowpea and maize with cowpea were applied to nitrogen (N2) levels as urea 0, 100, 150kg ha-1 and 0, 150, 220 kg/ha, respective...

British chemist Humphry Davy is best known for being the first person to isolate several elements, including sodium and calcium. Davy carried out his work electrolytically more than 200 years ago as an early experimenter with batteries. Less known about Davy is that during experiments on water electrolysis, in which water is split into hydrogen and oxygen, he found that ammonia formed on the ca...

One of the principal aims of alternative cropping systems is to minimize excessive loss of N while maximizing N use efficiency and meeting crop N requirements. Many such cropping systems substitute intensive application of synthetic fertilizer with organic inputs, such as N2-fixing legumes. The effectiveness of legume residues as a N source for subsequent crops depends heavily on temporal N rel...

This field experiment was established in Eastern Cameroon to examine the effect of selected rhizobial inoculation on N2-fixation and growth of Pueraria phaseoloides. Treatments consisted of noninoculated and Bradyrhizobium yuanmingense S3-4-inoculated Pueraria with three replications each. Ipomoea batatas as a non-N2-fixing reference was interspersed in each Pueraria plot. All the twelve plots ...

There is currently limited understanding of the contribution of biological N2 fixation (diazotrophy) to the N budget of large river systems. This natural source of N in boreal river systems may partially explain the sustained productivity of river floodplains in Northern Europe where winter fodder was harvested for centuries without fertilizer amendments. In much of the world, anthropogenic pol...

Plant growth-promoting rhizobacteria (PGPR) of the genus Pseudomonas have been reported to increase the yield of nonleguminous plants. Inoculation with Pseudomonas has been found by some authors to improve nodulation of legumes. This work examined the response of various legumes to a combined inoculation with Pseudomonas and nodule bacteria in pot experiments under field conditions in gray fore...

Nitrogen supplied by N2 fixation to soybean [Glycine max (L.) Merr.] may not be sufficient to maximize yield. Field studies were conducted in 2002, 2003, and 2004 on Sharkey clay soil (very-fine, smectitic, thermic Chromic Epiaquert) at Stoneville, MS (33 269 N lat). The objective was to determine the effect of high rates of N applied as a replacement for N2 fixation in nonirrigated and irrigat...

Genetic manipulation of nitrogenase and key glutamate-forming enzymes can provide mutants that excrete fixed N2 as NH4+. A derepressed N2 fxation mutant (SK-24) has been isolated , which excretes up to 20.2 mumol of fixed N2 as NH4+ per mg of cell protein in 24 hr at room temperature. Biochemical analysis shows that this mutant, which requires glutamate for growth, releases fixed N2 as NH4+ int...

tion and nodulation, thus reducing N2 fixation capacity (Shibles, 1998). Application of N before planting or durNitrogen application during soybean [Glycine max (L.) Merrill] ing the early growth stages can suppress the N2 fixation reproductive stages has the potential to increase soybean productivity. The objective of this study was to determine the impact of N fertilizer process. Fertilizer N...