ABSTRACT
Yield and disease incidence were evaluated in potato (Solanum tuberosum, cv. Atlantic) after six years of cultivation in succession with corn (Zea mays, cv. ‘AG 6080’) under conventional tillage (CT, depth of tillage: 20 cm) or in succession with three grass species [Guinea grass (Panicum maximum, cv. Tanzânia), Palisade grass (Brachiaria brizantha, cv. Marandu) and corn] under deep tillage (DT, depth of tillage: 70 cm). Total tuber yield was higher in DT in average 36% the value obtained in CT (17.76 t/ha), with no effect of the grass species. Common scab (Streptomyces scabies) incidence was influenced by treatments, the highest (16.9%) and the lowest (9.5%) values being obtained in succession with corn and Guinea grass, respectively, both under DT. The lowest incidence of tuber greening at field (2.58%) was also recorded in Guinea DT, significantly lower than obtained in Corn CT (6.33%), possibly due to a more efficient ridging operation. Grass species showed different values of aboveground dry biomass production. Guinea grass (26.56 t/ha) was the most and Corn under CT and DT (5.72 and 5.56 t/ha, respectively, without ears) were the least productive ones. Soil density, macroporosity and resistance to penetration indices were significantly better with DT, the grass species affecting them in a minor degree. The deep tillage system is, therefore, recommended for potato cultivation regardless the grass species used for crop succession.
Keywords:
Solanum tuberosum; compaction; soil recuperation; crop succession.