the effect of full irrigation (fi), partial root-zone drying at two levels (receiving 75 percent of et (prd75), 55 percent of et (prd55)) and deficit irrigation treatments at the same levels (75 percent (di75) and 55 percent (di55)) under drip irrigation on nitrogen uptake and leaching in a maize field in sari agricultural sciences and natural resources university were carried out during years ...

A dynamic simulation model for the soil plant system is described. The model includes a number of main modules viz. a water model, a soil temperature model, a soil nitrogen model including a submodel for soil organic matter dynamics, and a crop model including a submodel for nitrogen uptake. The soil part of the model has a one dimensional vertical structure. The soil profile is divided into la...

California's dairies are the largest confined animal industry in the state. A major portion of these dairies, which have an average herd size of nearly 1000 animal units, are located in low-relief valleys and basins. Large amounts of liquid manure are generated and stored in these dairies. In the semi-arid climate, liquid manure is frequently applied via flood or furrow irrigation to forage cro...

Temperate forests receive some of the highest rates of nitrogen (N) deposition in the world. While numerous studies have investigated the effects of N enrichment on forests, there is little consensus on why some forests become N saturated while others do not. To investigate this, we used a multi-factor metaanalysis to simultaneously estimate the relative importance of several environmental, exp...

Batch leaching tests were employed to investigate the leaching potential of arsenic (As) and selenium (Se) from two fly ash samples. The effect of pH and solid-to-liquid (S/L) ratio on As and Se leaching was examined in this preliminary study. Maximum As leaching occurred at pH 7-8, and soluble As concentration slightly increased with decrease of S/L ratio. Se displayed consistently increasing ...

Direct grazing of winter forage crops to feed non-lactating, pregnant dairy cows prior to calving is a common management practice in the New Zealand South Island. However, the high crop yields per hectare grazed, combined with a high stocking density of cows, means this potentially leads to large amounts of urinary nitrogen (N) deposited on bare, wet soil, that in turn, could lead to high nitra...

Field experiments were carried out in Huantai County from 2006 to 2008 to evaluate the effects of different nitrogen (N) fertilization and irrigation management practices on water leakage and nitrate leaching in the dominant wheat–maize rotation system in the North China Plain (NCP). Two N fertilization (NF1, the traditional one; NF2, fertilization based on soil testing) and two irrigation (IR1...

The decline in water quality in Lake Taupo has been attributed to nitrogen (N) leaching from surrounding land areas. Pastoral agriculture has been identified as a significant contributor to this N transfer to the lake through animal urine deposition. There is therefore an immediate need for new management options to reduce N losses. The objective of this study was to measure the effectiveness o...