Spatial and temporal variability of productivity of coffee plants grown in an experimental field located in Três Pontas, Brazil

Received: January 31st, 2023 ; Accepted: April 25th, 2023 ; Published: September 5th, 2023 ; Correspondence: [email protected] coffee grower seeks to increase productivity, as well as reduce the operating costs of his crop. Precision Agriculture (PA) is composed of a cycle of tools and technologies that can bring a good return to coffee growers, seeking to optimize production processes, bringing better yields and minimizing costs. Therefore, the objective of this research is to evaluate the spacetime behavior of productivity in a coffee plantation, aiming to apply AP techniques. The study was carried out in a coffee plantation of the species (Coffea arabica), cultivar Topázio MG1190, located in the municipality of Três Pontas, Brazil, with an area of 1.2 ha. With the aid of a GNSS RTK, 30 plants were georeferenced, from which their yields were later sampled in the years 2020, 2021 and 2022. The collected data were evaluated in two statistical processes in the RStudio software. The first stage consisted of a one-way analysis of variance with repeated measures, from the results it is concluded that there are differences between the production averages when buying the productivity of the years 2020, 2021 and 2022 and, in addition, the coefficient of variation for the three sets of samples was quite high (CV > 30%) indicating a heterogeneity between the data. The second stage consisted of a geostatistical analysis the data were fitted in a model and interpolated by ordinary kriging; the result was maps of spatial variability. Through these maps it was possible to evaluate the behavior of productivity spatially and temporally, as well as to quantify areas that had higher and lower levels of this attribute. It is concluded that productivity, even in the case of such a small productive area, can vary substantially in space and time, and the use of PA can help producers in decision making regarding management

Spatial variability of chlorophyll and NDVI obtained by different sensors in an experimental coffee field

Received: January 31st, 2024 ; Accepted: May 1st, 2024 ; Published: May 8th, 2024 ; Correspondence: [email protected] objective of this research was to study the spatial variability of NDVI and chlorophyll sampled by different sensors, as well as to evaluate the correlation between them in a coffee field. The study was carried out on a coffee farm located in the municipality of Três Pontas, Minas Gerais. A sampling grid containing 30 points was created for the study area. Each sampling point was represented by one plant, which was georeferenced by a GNSS RTK. For each sample plant, NDVI and chlorophyll were obtained by the optical and active sensors GreenSeeker and ClorofiLOG, respectively. In addition, it was carried out a flight with an RPA equipped with a passive and multispectral sensor. Using the data obtained by active sensors, a geostatistical analysis was carried out to evaluate the spatial variability of NDVI and chlorophyll. The geostatistical analysis verified the existence of spatial dependence for the two attributes, and thus it was possible to generate spatialization maps through kriging. The images obtained by the passive sensor resulted in five multispectral orthomosaics, making it possible to calculate the NDVI, thus generating a spatialization map of this index. It was possible to observe in the generated maps, points that presented a certain similarity and for this purpose a correlation analysis was carried out for the values of each attribute, sampled directly in the maps, and in different sampling grids (30, 60, 90 and 120 points). By analyzing the Pearson coefficient (R) it was possible to quantify the level of correlation between the data obtained by the different sensors and through the t test it was possible to find significant correlations between them

Composição química e degradabilidade in situ da ração em ovinos em área de caatinga no sertão de Pernambuco Chemical composition and in situ digestibility of diets for sheep in the caatinga region

Objetivou-se avaliar o efeito do tipo de fístula e da hora de coleta sobre a composição química e a degradabilidade in situ da ração em ovinos criados na caatinga. Foram utilizados dez ovinos mestiços de Santa Inês (cinco com cânula no rúmen e cinco com cânula no esôfago) recebendo água e mistura mineral ad libitum. Os percentuais de matéria seca (MS) variaram de 11,99 a 25,28%, matéria mineral (MM), 10,92 a 14,44%, proteína bruta (PB), 10,64 a 17,19%, extrato etéreo (EE), 2,95 a 4,77%, fibra em detergente neutro (FDN), 54,83 a 63,14%, fibra em detergente ácido (FDA), 39,40 a 46,62%, proteína insolúvel em detergente neutro (PIDN), 49,74 a 57,95%, proteína insolúvel em detergente ácido (PIDA), 28,52 a 39,15%, carboidratos totais (CT), 65,40 a 72,73%, carboidratos não-fibrosos (CNF), 5,47 a 12,86%, fenóis totais (FT), 0,37 a 0,52%, taninos totais (TT), 0,16 a 0,28% e taninos condensados (TC), 1,28 a 6,24%, respectivamente. A degradabilidade potencial variou de 48,25 a 64,63% para MS; 36,43 a 54,34% para FDN; e de 62,13 a 77,24% para proteína; a fração B, de 35,77 a 47,78% para MS; 33,28 a 50,38% para FDN; e 35,44 a 56,09% para proteína; a fração C, de 4,60 a 13,40% para MS; 3,84 a 8,42% para FDN; e 5,37 a 14,36% para proteína; a fração A, 9,74 a 18,13% para MS; 2,16 a 4,41% para FDN; e 20,21 a 31,49% para proteína; a degradabilidade efetiva para a taxa de passagem de 2%/hora, de 43,28 a 55,71 para MS; 29,21 a 36,54 para FDN; 55,84 a 67,49 para proteína; e a degradabilidade efetiva para a taxa de passagem de 5%/hora, de 37,60 a 47,27 para MS; 23,02 a 33,33 para FDN; e 45,74 a 59,99 para proteína. A composição química e a degradabilidade in situ da ração em ovinos foi influenciada pelo mês de avaliação. A dieta apresentou baixa digestibilidade in situ da MS, FDN e PB. A fistula ruminal, em comparação à fistula de esôfago, permitiu melhor avaliação da dieta, em virtude da recuperação total da extrusa.<br>This work was conducted with the objective of evaluating the effect of the type of fistula and time of collection on the chemical composition and in situ digestibility of dry matter, neutral detergent fiber and crude protein in the caatinga region. The experiment was conducted between September 2004 and July 2005. Ten Santa Inês castrated sheep, five with permanent ruminal cannula and five with esophageal cannula, were used. Samples were collected from both cannulas at 7:00 am and 2:00 pm. Sheep had free access to water and mineral mix. The percentage of DM, MM, CP, EE, NDF, ADF, NDIP, ADIP, CHOT, NFC, FT, TT and TC ranged from 11.99 to 25.28%; 10.92 to 14.44; 10.64 to 17.19%; 2.95 to 4.77; 54.83 to 63.14%; 39.40 to 46.62%; 49.74 to 57.95; 28.52 to 39.15; 65.40 to 72.73; 5.47 to 12.86%; 0.37 to 0.52%; 0.16 to 0.28%; and from 1.28 to 6.24%, respectively. Potential degradability (%), fraction B (%), fraction C (%/h), fraction A (%), effective degradability and passage rate of 2 and 5%/h ranged from 48.25 to 64.63; 35.77 to 47.78; 4.60 to 13.40; 9.74 to 18.13; 43.28 to 55.71 and 37.60 to 47.27 for dry matter; from 36.43 to 54.34; 33.28 to 50.38; 3.84 to 8.42; 2.16 to 4.41; 29.21 to 36.54; 23.02 to 33.33 for neutral detergent fiber and from 62.13 to 77.24; 35.44 to 56.09; 5.37 to 14.36; 20.21 to 31.49; 55.84 to 67.49; 45.74 to 59.99 for protein, respectively. The chemical composition and in situ digestibilility of diets for sheep in caatinga is influenced by the month of evaluation. The diet for sheep in the caatinga region presented low in situ digestibility of dry matter, neutral detergent fiber and crude protein. Ruminal cannula instead of esophageal cannula can be used to characterize the chemical composition and degradability of diet consumed by small ruminants