Modeling phosphorus in the environment - Chapter 17 (end) pptx

... Modeling of Phosphorus 413 17. 10 SUMMARY Much progress has been made in the modeling of P in the environment over the past 30 years. To continue this progress, the following improvements to modeling ... Georgia, Athens, GA CONTENTS 17. 1 Introduction 405 17. 2 Runoff 406 17. 3 Soil Phosphorus Pools and Model Parameters 406 17. 4 Leaching of Phosphorus 408 17....

Ngày tải lên: 12/08/2014, 00:22

... working on a modeling approach to BMP evaluation (see Chapter 15 on BMPs in this book; Gitau et al. 2001). An initial step in modeling BMP-induced reduction in P loss is the characterization of the ... overlying waters. In the short term, however, river flow and physical properties of the sediments will in uence the amount of sediment P leaving the watershed in th...

Ngày tải lên: 12/08/2014, 00:21

... LLC 44 Modeling Phosphorus in the Environment field (drainage) boundary to the outlet of the field. This length and difference in elevation from the most remote point to the outlet are the same ... rain falling during the time of concentration, R tc , was proportional to the amount of rain falling during the 24-h period, or where α tc is the fraction of daily rai...

Ngày tải lên: 12/08/2014, 00:21

... on the size and spacing of the drains (van der Ploeg et al. 1999). Models described in the following chapters simulate tile drain flow in a variety of ways, including the Richards equation linked with ... routines depicting P leaching in the soil profile. Recent interest in determining P leaching losses may lead to alternative methods for modeling P leaching. Simplified forms...

Ngày tải lên: 12/08/2014, 00:22

... Novak et al. 2003). Phosphorus 124 Modeling Phosphorus in the Environment The concept of sediment EPC 0 might provide a useful mechanism to simulate in- stream processes in these watershed models. ... detailed in Figure 5.1. The sediments were placed in the fluvarium to a 3-cm depth, and water was recir- culated over the sediment at a rate representing the average...

Ngày tải lên: 12/08/2014, 00:22

... rejecting a model because of errors in the data. Thus, in the case of the grazing inputs and the imbalance in the hydrological fluxes, it is argued that the rejection criteria should be relaxed as the model ... assess- ing the inputs at the measurement scale, together with interpolation errors in space and time to provide the values required at the lumped or distr...

Ngày tải lên: 12/08/2014, 00:22

... Sorption 171 7.2.4 Leaching 173 7.2.5 Fertilizer Application 173 7.2.6 Phosphorus Uptake by Plants 174 © 2007 by Taylor & Francis Group, LLC 174 Modeling Phosphorus in the Environment 7.2.6 PHOSPHORUS ... Group, LLC 178 Modeling Phosphorus in the Environment Green-Ampt in ltration equation, an improved weather generator, the ability to read in daily...

Ngày tải lên: 12/08/2014, 00:22

... was delineated into FIGURE 8.4 Upper Etowah River basin with the solid dot indicating the watershed outlet at Canton, Georgia. The gray lines indicate the stream network, and the dark lines indicate ... LLC 212 Modeling Phosphorus in the Environment modeling water movement in HSPF. Donigian and Love (2003) and U.S. Environ- mental Protection Agency (2006) are helpful...

Ngày tải lên: 12/08/2014, 00:22

... (g/ha) Oct-96 Mar-97 Sep-97 Mar-98 Sep-98 Mar-99 Sep-99 Mar-00 Sep-00 Time (months) 1200 1000 800 600 400 200 0 Observed Predicted Total P loss (g/ha) Oct-96 Mar-97 Sep-97 Mar-98 Sep-98 Mar-99 Sep-99 ... change in the input leads to a 1% relative change in the output. A negative value indicates that input and output are inversely related. The greater the absolute value of the in...

Ngày tải lên: 12/08/2014, 00:22

... net gain of sediments. sed_loss Value -8 35 - -7 50 -7 50 - -6 00 -6 00 - -4 50 -4 50 - -3 00 -3 00 - -1 50 -1 50 - 0 0 -1 50 150 - 300 300 - 450 © 2007 by Taylor & Francis Group, LLC 241 10 ANSWERS-2000: ... represents the storage volume at the end of the time increment. The value of Po j+1 is then replaced into Equation...

Ngày tải lên: 12/08/2014, 00:22