Variations in yields are due mainly to variation in climate, genetics, and the level of intensive farming techniques (use of fertilizers, chemical pest control, and growth control to avoid lodging).
vˌɛɹɪˈeɪʃənz ɪn jˈiːldz ɑːɹ dˈuː mˈeɪnli tə vˌɛɹɪˈeɪʃən ɪn klˈaɪmət, dʒɪnˈɛɾɪks, ænd ðə lˈɛvəl ʌv ɪntˈɛnsɪv fˈɑːɹmɪŋ tɛknˈiːks jˈuːs ʌv fˈɜːɾəlˌaɪzɚz, kˈɛmɪkəl pˈɛst kəntɹˈoʊl, ænd ɡɹˈoʊθ kəntɹˈoʊl tʊ ɐvˈɔɪd lˈɑːdʒɪŋ.