Effects of animal manure upon growth of Cerrado plants

Abstract

Through excretion, animals return to the soil part of the nutrients they ingest. This input can be an alternative to artificial inorganic fertilization aiming at increasing soil nutrient concentrations in degraded areas that are prone to restoration. In nutrient-poor soils, the addition of animal manure can promote increases in soil fertility, but studies assessing its effects upon plant communities are meager. This study aims at checking whether the addition of manure originated from livestock promotes plant growth increase and enzyme activity in Cerrado native plants of different functional groups as a way to subsidize processes of environmental recuperation in degraded areas using organic fertilization of an easily available source, as animal manure. The experiment was conducted in a screenhouse through a completely randomized design with four manure and six species treatments with three replicates. Manure treatments used were control, cattle, sheep and goat manure. The plant species selected belonged to main Cerrado herbaceous functional groups – two naturalized grasses, two alien invasive grasses, a legume herb and a Malvaceae herb. Phosphorus and nitrogen concentrations, and N:P ratios varied according to the type of manure. Soil organic matter content, phosphorus and potassium concentrations increased upon manure addition. Different manure types promoted various effects in height, biomass and acid phosphatase activity amongst the plants. Goat and cattle manure positively influenced Urochloa decumbens, an exotic invasive grass living in the Cerrado, whereas sheep manure addition promoted increase of non-invasive grasses. These results show that animal manure can promote better nutrient conditions for plants living in degraded areas, but the selection of the manure type for application in restoration projects aiming at aiding plant growth in Cerrado degraded areas will depend on the purpose of the project because different dung types benefit different plant functional groups.