Recycling soil nitrate nitrogen by amending agricultural lands with oily food waste.
With current agricultural practices the amounts of fertilizer N applied are frequently more than the amounts removed by the crop. Excessive N application may result in short-term accumulation of nitrate nitrogen (NO3-N) in soil, which can easily be leached from the root zone and into the ground water. A management practice suggested for conserving accumulated NO3-N is the application of oily food waste (FOG; fat + oil + greases) to agricultural soils. A two-year field study (1995-1996 and 1996-1997) was conducted at Elora Research Center (43 degrees 38' N, 80 degrees W; 346 m above mean sea level), University of Guelph, Ontario, Canada to determine the effect of FOG application in fall and spring on soil NO3-N contents and apparent N immobilization-mineralization of soil N in the 0- to 60-cm soil layer. The experiment was planned under a randomized complete block design with four replications. An unamended control and a reference treatment [winter wheat (Triticum aestivum L.) cover crop] were included in the experiment to compare the effects of fall and spring treatment of oily food waste on soil NO3-N contents and apparent N immobilization-mineralization. Oily food waste application at 10 Mg ha(-1) in the fall decreased soil NO3-N by immobilization and conserved 47 to 56 kg NO3-N ha(-1), which would otherwise be subject to leaching. Nitrogen immobilized due to FOG application in the fall was subsequently remineralized by the time of fertilizer N sidedress, whereas no net mineralization was observed in spring-amended plots at the same time.
Rashid
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Institute of Natural Resources and Environmental Sciences, NARC, Park Road 45500, Islamabad, Pakistan. trashid256@yahoo.com
Voroney
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RP
D000383:Agriculture; D003247:Conservation of Natural Resources; D005308:Fertilizers; D019649:Food Industry; D009584:Nitrogen / Q000737:chemistry / Q000302:isolation & purification*; D009821:Oils; D012037:Refuse Disposal; D012621:Seasons; D014908:Triticum; D014876:Water Pollution
D005308:Fertilizers; D009821:Oils; D009584:Nitrogen