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近二十年来,美国棉花单产有所提高,亩产皮棉由42.7斤增为73.9斤。1.选用优良品种,加强种子管理。五十年代以来,在大量缩减棉田的情况下,为了提高棉花产量,实行一地一种制。只有经过州试验站试验确实比原有品种增产、品质符合标准、在作物种植协会登记的品种,才可以推广,只有持有检验证书的注
In the past two decades, the yield of cotton in the United States has been raised, with the output of cotton lint increased from 42.7 to 73.9 kg per mu. 1. Selection of fine varieties, strengthen seed management. Since the 1950s, with a large reduction of cotton fields, a system of one place has been put in place to increase cotton production. Only through the State Experimental Station test does yield more than the original varieties, quality standards, registered varieties in the crop cultivation association, can promote, only hold the certificate of the test Note