The sequestration of carbon and nitrogen by clay-sized particles in soils is well established, and clay content or mineral surface area has been used to estimate the sequestration potential of soils. Here, via incubation of a sieved (<2 mm) topsoil with labelled litter, we find that only some of the clay-sized surfaces bind organic matter (OM). Surprisingly, <19% of the visible mineral areas sh...

to assess the effects of different levels of nitrogen and phosphorous on yield and nutrient use efficiency of sugar beet (polygerm seed (cv. 7233)), this study was carried out in 1999-2001 in ardabil agricultural research station (alarough). the experiment contained two factors of: nitrogen in 4 levels (control, 100, 200 and 300 kg n/ha) and phosphorous in 3 levels (control, 100 and 200 kg p2o5...

The effect of integrated use of mineral and organic N sources (farmyard manure, poultry manure, and Filter Cake) on yield and N uptake of wheat were assessed in biennial field experiment carried out on silty clay loam soil in Nuclear Institute for Food and Agriculture, Tarnab, Peshawar Pakistan during 2005-07. Combined dose of N provided from all sources was applied @120 kg ha-1. There were 17 ...

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Crop production is the single largest cause of human alteration of the global nitrogen cycle. We present a comprehensive assessment of global nitrogen flows in cropland for the year 2000 with a spatial resolution of 5 arc-minutes. We calculated a total nitrogen input (IN) of 136.60 trillion grams (Tg) of N per year, of which almost half is contributed by mineral nitrogen fertilizers, and a tota...

Although the nitrogen nutrition index (NNI) is a widely used indicator of plant nitrogenstatus, no model of NNI calculation for spring barley (Hordeum vulgare) reflecting also specificmalting requirements on grain has been published. The aim of this study was to determinean optimal range of the nitrogen nutrition index (ratio of nitrogen concentration in shootbiomass to critical nitrogen concen...

An approach is outlined for synthesising current understanding of nitrogen dynamics in natural grasslands and extensively managed grassland systems. The increasing complexity of models is illustrated from recent literature, first conceptualising and eventually process-simulating the dynamics of nitrogen, especially in the soil sub-systems of grasslands. Some comparisons are made between New Zea...

Ninety, day old broiler chicks were arranged into 5X3X6 pattern to investigate the effect of exclusion of Cobalt, Iron and Copper from the mineral mixture. Five dietary groups (T1 to T5) were assigned basal diets containing 2800 kcal ME/kg and 22% CP (Starter) and 20% (Finisher) for a total duration of 6 weeks. The chicks in T1 were fed commercial mineral mixture, T2 were supplemented with mine...

Ectomycorrhizal fungi allow their host plants access to organic forms of N through enzymatic mineralization of the substrate and enhanced absorption of amino acids and mineral N. The cost to the plant is carbohydrates that support fungal growth and metabolism. Enrichment of soils with mineral N, as through atmospheric deposition, may affect the growth and function of these fungi by direct effec...