I - Aspects>                                                                                            

A - Monocultures                                                                                                                     

1) Traditionnelles                                                                                                                     

a) Dairy Belt ou Milk Belt (lait)                                                                                                 

     1- Production ancienne: Michigan, Minnesota, Wisconsin                                                  

     2- Production moderne: Oregon et Washington                                                                  

b) Tobacco Belt (Tabac)                                                                                                          

         Virginie, les deux Carolines                                                                                            

c) Cotton Belt (coton)                                                                                                               

         De la Georgie au Sud du Texas                                                                                      

d) Corn Belt (maïs)                                                                                                                   

       Ohio, Indiana, Illinois, Iowa, Missouri, Nebraska                                                               

       (Nouvelles cultures:soja, sorgho, avoine, orge)                                                                  

e) Wheat Belt (Blé)                                                                                                                   

    1- Blé du printemps au Nord (Montana, les deux Dakotas)                                                   

    2- Blé hiver au Sud (Kansas, Nebraska, Oklahoma)                                                              

2) Modernes                                                                                                                             

    a) Agrumes (Floride)                                                                                                             

    b) Cannes à sucre (Texas)                                                                                                    

    c) Riz (Louisiane, Arkansas)                                                                                                  

    d) Culture maraîchère (près des grosses villes)                                                                      

    e) Arachides (Plaines atlantiques)                                                                                        

    f) Pommes de terre (Maine)                                                                                                  

B - Polycultures                                                                                                                       

1) Pauvres: Ozark, plateaux de Cumberland, Appalaches                                                        

2) Riches (par irrigation)                                                                                                           

   a) Californie (vergers subtropicaux et tempérés)                                                                    

   b) Oasis du Nord (Utah): luzernes, bettraves, fruits                                                                 

   c) Oasis du Sud (Idaho): citron, dattes, figues, coton                                                             

C - Culture sèche (Dry farming)                                                                                               

    Mise au point en Utah au XIXème s.                                                                                    

    Humidité du sol entretenue par un travail en surface                                                           

    Cultures céréalières sur de grandes régions sèches (Washington, Montana)                         

    Consommation d'engrais: 40Kg/an                                                                                      

    Pesticides: usage intensif                                                                                                     

D - Élevage Spécialisé                                                                                                           

1) Le Ranching                                                                                                                        

   a) Boeufs transhumants (vers Idaho, Montana, Washington)                                                  

    (dans le Wyoming et les Etats de la Plaine)                                                                         

   b) Boeufs non transhumants (Mississipi et Sud de la Plaine)                                                 

Bovins: 99.4 millions                                                                                                                

Vaches à lait: 10.1 millions                                                                                                      

Moutons: 11.4 millions                                                                                                             

Porcs: 53.8 millions                                                                                                                  

2) Volailles                                                                                                                               

   a) Poulet (Rhode Island): 1550 millions                                                                                

   b) Dinde (Vermont) 3.1 millions                                                                                            

                                                                                                                                                     

                                                                                                                                                     

                                                                                                            

II - Fondements                                                                                 

A - Terres (en millions d'hectares)                                                             

a) Terres agricoles: 57%                                                                              

    1- Terres labourables: 191                                                                         

    2- Prairies permanentes: 244                                                                      

    3- Forêts pâturées: 80                                                                              

    4- Divers: 4                                                                                           

b) Terres non agricoles: 43%                                                                         

    1- Forêts: 212                                                                                        

    2- Parcs et réserves naturelles: 33                                                               

    3- Villes, autoroutes et aéroports: 26                                                             

    4- Divers: 127                                                                                        

B - Climat favorable à l'agriculture                                                              

    1- Méditérannéen sur la façade pacifique sud                                                  

    2- Tropical sur la façade du golfe du Méxique                                                   

    3- Tempéré dans les Grandes Plaines                                                            

C - Les sols fertiles                                                                                 

    1- Sol brun forestier sur la façade atlantique                                                    

    2- Sols alluvieux fertiles au Middle West                                                         

D - Les facteurs humains                                                                          

    1- L'agriculture commerciale (ou spéculative)                                                   

        C'est l'agriculture dont les productions sont destinées à l'exportation                    

        Exportations: blé (30,6%), maïs (44,5%)                                                      

    2- L'agriculture vivrière (ou de subsistance)                                                    

        C'est l'agriculture destinée à la consommation locale                                        

    3- L'agroalimentaire (Il emploie: 1.5% de la population active)                                 

        C'est une filière de production industrielle qui transforme les produits agricoles en aliments    

    4- L'agrobusiness                                                                                   

        C'est l'ensemble des activités centrées sur la production agricole et nécessitant des capitaux    

        importants (équipements, transformations de produits…)                                  

        ex: Philipp Morris (Tabac - 1er rang mondial) - Pepsico (Boisson - 4ème rang mondial)     

             Conagra (Alimentation - 5ème rang mondial) - Coca Cola (Boisson - 8ème rang mondial)    

E - L'irrigation                                                                                         

    a) Elle joue un rôle primordial  dans le déplacement des Belts                                 

            ex: déplacement de la Cotton Belt du Nord au Sud                                        

    b) Évolution positive de l'irrigation dans les villes les moins agricoles                        

            ex: Californie (par l'irrigation, cet état est devenu le plus important au niveau de la valeur    

                                 productive agricole)                                                            

F - Feed Lots                                                                                          

     Mode de production très efficace                                                                

     Ce sont des parcs d'engraissement artificiels pour les bovins et les ovins                

III - Limites / Contraintes                                                                  

A - Dangers de la monoculture                                                                  

     1) Usure des sols                                                                                   

     2) Érosion                                                                                            

     3) Revenus variables selon la récolte                                                            

     4) Les excédents de la production (surproduction)                                            

         Pour écouler la surproduction, l'Etat intervient et tente d'assurer des marchés exterieurs:    

         Débats de l'Uruguay Round (1986-1990) à l'OMC entre les Etats-Unis et l'Union Européenne      

         où ils se mettent d'accord à ce que les EU assurent un marché en Europe pour les Farmers    

         et réduisent les importations des produits agricoles européens.                          

         (Les aides se terminent en 2002)                                                              

B - Le probème de la sécheresse à l'ouest                                                  

     Elle est liée à la continuité et à la position de l'abri                                              

     Le climat désertique, le rôle négatif de la poussière                                           

     La végétation aride                                                                                 

C - Le problème des exploitations familiales, petites et moyennes                 

     Ces exploitations disparaîssent                                                                   

     Sur 700.000 fermiers, 56.000 fournissent les 2/3 de la production agricole                

     Endettement surélevé des fermiers (Farmers)                                                  

D - Compétitivité des produits agricoles                                                      

     Concurence des produits américains avec la C.É.E, l'Argentine, le Canada et l' Australie.    

                                                                                                                                                     

                                                                                                            

                                                                                                            

                                                                                                            

 * Les productions agricoles                                                                     

                                          Part de la production mondiale                      Rang mondial         

  Blé                                                    10.6%                                                3ème                 Maïs                                                  40.9%                                                1er                   Arachides                                            5.7%                                                4ème               Soja                                                   49.8%                                               1er                   Sucre                                                   5.1%                                               4ème                Agrumes                                             15.5%                                               2ème               Vin                                                    16.9%                                               4ème            Bovins                                                  7.8%                                               4ème               
Porcins                                                6.3%                                               2ème