Initial absolute growth dynamic of neem under supplemental irrigation with saline waters and biofertilizer

Abstract

The growing need to increase food production constitutes a serious scientific-technological challenge, requiring the expansion of cultivated sites also with the utilization of degraded areas, such as soils affected by salts. In order to achieve that, alternatives to mitigate such limitations have been pursued, such as the use of biofertilizers in the formation process of neem seedlings. In the pursuit for alternative and ecological control methods considered healthy and sustainable, the use of the neem tree (Azadirachta indica) associated with organic inputs in semiarid regions is highlighted, since this species possesses azadirachtin as the main bioactive compound, capable of acting against more than 418 plague species due to its insecticidal properties. An experiment was conducted in a screened plant nursery in the municipality of Areia – PB, in the period from January to July 2016, to evaluate the effects of the supplemental irrigation with saline waters on the absolute growth of neem seedlings in soil with biofertilizer. The substrate was a Dystrophic Red- Yellow Latosol. The experimental design was in randomized blocks, in a 5x2x3 factorial scheme, with four replications. The treatments were irrigated with five levels of water salinity (0.5; 1.5; 3.0; 4.5; 6.0 dS m-1), in the soil without and with common fermented bovine biofertilizer, and evaluated after three periods: 30, 60, and 90 days after the emergence of the plantlets, for the determination of the absolute growth in AP, DC, IAF, MSR, MSPA, and MST. The liquid fermented biofertilizer, after diluted, was applied a single time in a 1:3 proportion, two days before sowing, at the level of 10% the volume of the substrate. The treatments with fermented bovine biofertilizer provided better conditions for the growth and development of the neem through osmotic effect than in the soil without the input as a function of the time.