Alternatives for soil fertility reclamation in shift cultivation system in northeast Para.

Abstract

In a secondary vegetation area of Marapanim-PA county and using a completely randomized plot design, with four replicates, the factors slash-and-trituration practice, rock phosphate and green manure were tested as agroecology alternatives for soil fertility reclamation, through the following treatments: secondary vegetation; control; rock phosphate (RP); wonderbean [Canavalia ensiformis (L.) D.C.] (W); RP + W; RP + pigeonpea [Cajanus cajan (L.) Millspaugh] (P); RP + tithonia [Tithonia diversifolia (Hemsl.) A. Gray] (T); W + P; and W + T. The soil preparation for planting the cassava–corn sequential cropping was made by slash-and-trituration of the secondary vegetation. The treatments of soil fertility restoration only affected positively the corn production variables, and higher impacts were observed for rock phosphate with pigeonpea, followed by rock phosphate with wonderbean, and rock phosphate alone. In slash-and-trituration conditions and in terms of organic matter and available phosphorus, the higher positive impact in soil fertility occurred under rock phosphate with pigeonpea treatment, which reflected in corn production. Different from tithonia, pigeonpea clearly took advantage of rock phosphate.