المغذيات النباتية و أعراض نقصها و البدائل الطبيعية للتخصيب في نظم الزراعة العضوية

[عبير العبير]

محاصيل البقول الرئيسية وتقديرات لكميات النتروجين المثبتة بواسطتها

Crop and N-Flxing Bacteria Annual N2 Flxation
Range (kg/ha/year) Typical Value (kg/ha/year)
Host Plant Rhlzoblum
Alfalfa R. Melll otl 60 - 500 225
Clovers R.trlfolll 60 - 350 115
Peas, Vetch R. legumlnosarum 90 - 180 100
Beans R. Phaseoll 20 - 100 45
Host Plant Brabyrhlzoblum
Luplns B. luplnll 150 - 170 160
Soybeans B. Japonlcum 65 - 200 100
Cowpea B. Parasponlae 65 - 130 100
Note: Rhizobium are fast-growing symbiotic bacteria: Bradyrhizobium are slow growing b. Average values from various sources. Organic wastes as a source of nitrogen

Representative Values for Nitrogen and Availablity for Selected Oganic Wastes.
Organic N Source Total N(%) Organic N Mineralized a (%)
Animal Manure
Beef 1.3-1.8 25-35
Dairy 2.5-3.0 25-40
Poultry 4.0-6.0 50-70
Swine 3.5-4.5 30-50
Biosolids
Aerobic digestion 3.5-5.0 25-40
Anaerobic digestion 1.8-2.5 10-20
Composted 0.5-1.5 (-10)-10
Other Wastes
Fermentation 3.0-8.0 20-50
Poultry Processing 4.0-8.0 40-60
Wastes 0.2-1.0 (-20)-5
Papermill Sludge
Note: Average values various sources.
a Organic N mineralized estimated from laboratory incubation studies.
Negative values for composts and papermill sludges indicates that immobilization of N occurred.

Nutrient removal Estimates For Selected Crops
Crop (Kg/frsh weight unless otherwise indicated)
Nitrogen Phosphate Potash CaO MgO
Rye 15 8 5 10 3
Wheat 15 8 5 6 3
Winter barley 20 8 5 10 4
Spring barley 18 8 5 10 3
Oats 17 8 5 6 4
Straw 5 3 13 5 1

Maize (+straw) 30 15 35 8 8
Maize (-straw) 20 8 5 - 2
Oil Seed rape 55 30 50 60 10

Potatos (main crop) 4.5 2 7 2 -
Potatoes ( early) 3 2 5 0.5 0.5
Sugar beet (+tops) 5 2 8 1.5 1.5
Sugar beet (-tops) 2 - 2.5 0.5 0.5

Lucerne* 30 8 20 25 4
Red clover* 30 7 25 22 5
White clover/grass* 10 3 5 20 5
Hay* 20 7 21 20 5