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start:hype_model_description:hype_np_soil [2019/05/09 08:18]
cpers [Crop cover and ground cover]
start:hype_model_description:hype_np_soil [2019/05/09 08:28] (current)
cpers [Crop cover and ground cover]
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 ==== Crop cover and ground cover ==== ==== Crop cover and ground cover ====
  
-Erosion can be mitigated by protective vegetation or vegetation residues that are in contact with the ground. Crop cover and ground cover erosion ​reduction are used for particulate phosphorus (PP) and the default sediment transport model (SS). The reduction is given by the fraction of coverwith full cover (1halting the erosion completely. Harvested crops have seasonally varying ground and crop cover, while permanent vegetation (e.g. forest) has constant values for these parameters. The input data needed for calculations (//ccmax1, ccmax2, gcmax1, gcmax2//) are given in [[start:​hype_file_reference:​cropdata.txt|CropData.txt]]. Parameters //ccmax1// and //gcmax1// describe the maximum crop and ground cover during spring-summer growing season, parameters //ccmax2// and //gcmax2// are corresponding maxima for winter crop's growth. These maximum ratios are reached at //maxday1// and //​maxday2//,​ which are defined as halfway between planting and harvest, and halfway between autumn planting and midwinter (1 January or 30 June depending on autumn planting date), respectively. ​ From sowing the coverage fractions increase linearly up to their maximum values. After these dates maximum coverage is maintained to the next ploughing, harvest, or until the growing season starts again in the spring (for winter crops) (Figure 4). During the period between harvesting and ploughing, crop cover is equal to ground cover (//​gcmax1//​). At ploughing, ground and crop cover are reduced to zero. Parameters //bd1// and //bd4// describe the dates of spring and autumn ploughing. In the case of spring sowing, when no winter crop is crowing, either one of the ploughing parameters can be set for ploughing date.+Erosion can be mitigated by protective vegetation or vegetation residues that are in contact with the ground. Crop cover and ground cover reduce ​erosion ​by rain and surface runoff ​for particulate phosphorus (PP) and the default sediment transport model (SS). Each crop covers a fraction of the groundthus for simultanous crops (1st and 2nd croptheir respective crop/ground cover is combined to a common crop/ground cover 
 + 
 +Harvested crops have seasonally varying ground and crop cover, while permanent vegetation (e.g. forest) has constant values for these parameters. The input data needed for calculations (//ccmax1, ccmax2, gcmax1, gcmax2//) are given in [[start:​hype_file_reference:​cropdata.txt|CropData.txt]]. Parameters //ccmax1// and //gcmax1// describe the maximum crop and ground cover during spring-summer growing season, parameters //ccmax2// and //gcmax2// are corresponding maxima for winter crop's growth. These maximum ratios are reached at //maxday1// and //​maxday2//,​ which are defined as halfway between planting and harvest, and halfway between autumn planting and midwinter (1 January or 30 June depending on autumn planting date), respectively. ​ From sowing the coverage fractions increase linearly up to their maximum values. After these dates maximum coverage is maintained to the next ploughing, harvest, or until the growing season starts again in the spring (for winter crops) (Figure 4). During the period between harvesting and ploughing, crop cover is equal to ground cover (//​gcmax1//​). At ploughing, ground and crop cover are reduced to zero. Parameters //bd1// and //bd4// describe the dates of spring and autumn ploughing. In the case of spring sowing, when no winter crop is crowing, either one of the ploughing parameters can be set for ploughing date.
  
 {{ :​start:​hype_model_description:​groundcover_cropcover.png?​400 |}} {{ :​start:​hype_model_description:​groundcover_cropcover.png?​400 |}}
start/hype_model_description/hype_np_soil.txt · Last modified: 2019/05/09 08:28 by cpers