Intercropping of Lettuce with Mint (Mentha piperita) Fertilized with Rooster Tree (Calotropis procera) Plus Cattle Manure

Abstract

Background: Intercropping lettuce and peppermint improves crop productivity and offers environmental and economic benefits. In Brazil’s semi-arid region, combining cattle manure with green manure from native species can reduce production costs and enhance soil fertility sustainably. Aim: The combined application of organic fertiliser sources plays a crucial role in promoting the optimal growth and development of horticultural and medicinal crops, particularly within intercropping systems. Place of Study: The experiment was conducted at the experimental farm of the Federal Rural University of the Semi-Arid Region (UFERSA), Brazil, located at latitude 5°03′37″ S and longitude 37°23′50″ W, at an altitude of 72 m above sea level. The study aimed to evaluate the intercropping of lettuce with mint (Mentha piperita) under fertilisation with a mixture of rooster tree (Calotropis procera) biomass and cattle manure. Study Design and Methodology: The experiment was arranged in a randomised complete block design using a 4 × 2 factorial scheme, with three replications. The treatments consisted of four application rates of a mixture of rooster tree (Calotropis procera) and cattle manure (0.0, 1.0, 2.0, and 3.0 kg m⁻²) combined with two cropping systems, namely monocropping and intercropping. Mint (Mentha piperita) Evaluated Characteristics: For mint (Mentha piperita) cultivation, the following characteristics were evaluated: biomass height, green mass, number of bunches and dry mass. Evaluation of Lettuce Crop Characteristics: plant height, number of leaves, production and dry matter mass. Conclusions: The soil application of the mixture of organic fertilizers [rooster tree (Calotropis procera) plus cattle manure] greatly contributed to the increase in productivity, with maximum values of 760.5 and 310.96 g m-2 for monocropping and intercropping cultivation, respectively, in the mint (Mentha piperita) and lettuce intercropping system at the dose of 3.0 kg m-2. In lettuce cultivation, the maximum values were 893.83 and 344.30 g m⁻² for monoculture and intercropped cultivation, respectively, at the rate of 3.0 kg m⁻². The intercropping system demonstrated potential for productive use of physical space, represented by the area-equivalent ratio (AER), with a maximum value of 1.45, in the quantity of 3.0 kg m-2 of rooster tree and bovine manure.