Using Bokashi and Cow Urine as Organic Low-Cost Amendments Can Enhance Arugula (Eruca sativa L.) Agronomic Traits but Not Always Total Polyphenols and Antioxidant Activity

Productive traits, total polyphenols (TPC), and antioxidant activity (DPPH) of arugula submitted to the combination (or not) of cow urine and doses of bokashi were evaluated in two experimental areas. Arugula was planted in cultivation bags with 55 dm(3) of capacity in protected cultivation. The treatments were bokashi doses (0, 10, 20, and 30 g) and use (or not) of cow urine diluted 1% in water. The variables evaluated were fresh leaf biomass (FLB), dry leaf biomass (DLM), plant height (PH), chlorophyll index, TPC, and DPPH. In area 1, all agronomic variables were increased at 30 g and 20 g bokashi doses. FLB was increased by 87 and 76% with 30 g of bokashi. Cow urine only increased PH. In area 2, the use of bokashi + cow urine increased FLB, DLB, and PH with a positive quadratic response. At the maximum point, the FLB was increased by 159% with 28.92 g of bokashi. Bokashi increased FLB and DLB in the two areas in all evaluated doses. For TPC, with the use of cow urine, 10 g of bokashi increased TPC by 14%. Without the use of cow urine, increases of 17 and 33% with 10 and 30 g of bokashi were observed. The 30 g of bokashi is recommended because of increased productive traits and TPC.