SPAD Index of Organic Corn in Consortium with Cover Crops and Coffee Straw

Abstract

Nitrogen is the most required nutrient by the corn crop and also the one that most limits yield. Organic fertilization is an economically viable and sustainable alternative for most farmers. The use of the portable chlorophyll meter allows instant measurements of the chlorophyll content in the leaf through the SPAD index and represents a promising alternative for assessing the level of nitrogen in plants. The objective of this work was to evaluate the SPAD index of maize in a consortium with legumes and coffee straw. The experiment was carried out with the following treatments: T1- Corn intercropped with common bean + mowing, T2- Corn intercropped with crotalaria + mowing, T3- Corn intercropped with jack bean + mowing, T4- Monoculture maize with coffee straw applied on surface + manual weeding, T5- Maize in monoculture and manual weeding and T6- Corn intercropped with pigeon pea + mowing. The treatments were arranged in a randomized block design with five replicates. Three readings corresponding to the chlorophyll index were made on the corn leaf with the SPAD Minolta 502 DL PLUS chlorophyll meter. The determinations with the chlorophyll meter were performed in vegetative stages V4 (four fully expanded leaves), V8 (eight fully expanded leaves) and reproductive R1 (flowering). It is concluded that the SPAD index is efficient in the initial stages of the corn crop and the use of coffee straw is beneficial for maize cultivation.