Clean quality control of agricultural and non-agricultural lime by rapid and accurate assessment of calcium and magnesium contents via proximal sensors.

Ca and Mg are the most important chemical elements in lime. Properly measuring Ca and Mg contents is essential to assess the quality of lime products. Quality control guarantees the adequate use of lime in industrial processes, in soils, and helps avoiding adulteration. Proximal sensors can aid in this process by determining Ca and Mg contents easily, rapidly and without producing chemical waste. The objective of this study was to evaluate the use an environmentally-friendly method of analyzing the quality of lime. We studied 1) the use of portable X-ray fluorescence (pXRF) to predict concentrations of Ca and Mg in lime, 2) tested if NixPro™ sensor can improve prediction accuracy and 3) tested if sample preparation methods (grinding) affect analyses. 74 samples of lime were analyzed by two different laboratories (lab. 1 = 38, lab. 2 = 36). All samples submitted to pXRF and NixPro™ analyses. Sensor analyses were done in whole (CP) and ground (AQ) samples to test the effect of sample preparation in prediction performance. High correlation was found between Ca and Mg contents measured via pXRF and laboratory analyses. Mg-CP presented the highest correlation coefficient (r = 0.81); Mg-AQ, the lowest (0.57). Predictions presented good performance (R2 > 0.68); Mg had the best results (0.86). Separating models per laboratory showed that some datasets are harder to model, probably due to variability in the source material (limestone). The addition of NixPro™ data contributed to improve prediction accuracy, although slightly. Predictions using CP samples presented the best results, especially for Mg, indicating that grinding is not necessary. This pioneer study demonstrated that fused proximal sensors can be used to rapidly and easily determine contents of Ca and Mg in soil amendments without producing chemical waste.

Growth and yield of the cowpea cultivar BRS Guariba inoculated with rhizobia strains in southwest Piauí / Crescimento e produtividade de feijão-caupi cultivar BRS Guariba inoculado com estirpes de rizóbio no sudoeste do Piauí

The interaction of cowpea with efficient strains of rhizobia in biological nitrogen fixation can allow increased yield, which can completely replace nitrogen fertilization and can reduce production costs. The aim of this study was to evaluate the response of cowpea cultivar BRS Guariba to inoculation with six strains of rhizobia (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 and BR 3262) in a field experiment conducted in the Southwest of Piauí. The experimental design was randomized blocks with eight treatments and four replicates, including the six cited strains and two uninoculated controls, one with mineral nitrogen (70 kg ha-1) and the other without mineral nitrogen. Nodulation, growth, yield, nitrogen accumulation in shoots and in grains and crude protein content in grains were evaluated. Strains under selection (UFLA 03-154 and UFLA 03-164) promoted yields that were higher compared to those obtained by strains authorized as inoculants (INPA 03-11B, BR 3267 and BR 3262). Inoculation with strains UFLA 03-84, UFLA 03-154 and UFLA 03-164 promoted yields equivalent to the control with mineral nitrogen (796.51 kg ha-1) and similar to the yield obtained with the control without mineral nitrogen and without inoculation, indicating efficient symbiosis of the indigenous rhizobia. UFLA 03-154 was better than the other treatments in terms of increased crude protein.(AU)

A interação do feijão-caupi com estirpes de rizóbio eficientes na fixação biológica de nitrogênio pode permitir o aumento da sua produtividade, sendo possível substituir totalmente a adubação nitrogenada e reduzir os custos de produção. Objetivou-se avaliar a resposta do feijão-caupi cultivar BRS Guariba à inoculação com seis estirpes de rizóbio (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 e BR 3262) em experimento conduzido em campo no Sudoeste do Piauí. O delineamento experimental foi em blocos casualizados com oito tratamentos e quatro repetições, sendo as seis estirpes citadas e dois controles não inoculados, um com nitrogênio mineral (70 kg ha-1) e outro sem nitrogênio mineral. Foram avaliados nodulação, crescimento, produtividade, acúmulo de nitrogênio na parte aérea e nos grãos e o teor de proteína bruta nos grãos. As estirpes em fase de seleção (UFLA 03-154 e UFLA 03-164) promoveram rendimento de grãos superiores aos obtidos pelas estirpes autorizadas como inoculantes (INPA 03-11B, BR 3267 e BR 3262). As inoculações com as estirpes UFLA 03-84, UFLA 03-154 e UFLA 03-164 proporcionam rendimento de grãos equivalentes ao controle com nitrogênio mineral (796,51 kg ha-1), porém, semelhantes ao rendimento obtido com o controle sem nitrogênio mineral e sem inoculação, indicando boa eficiência simbiótica das populações nativas de rizóbio. A UFLA 03-154 destacou-se dos demais tratamentos com relação ao aumento de proteína bruta.(AU)

Growth and yield of the cowpea cultivar BRS Guariba inoculated with rhizobia strains in southwest Piauí / Crescimento e produtividade de feijão-caupi cultivar BRS Guariba inoculado com estirpes de rizóbio no sudoeste do Piauí

The interaction of cowpea with efficient strains of rhizobia in biological nitrogen fixation can allow increased yield, which can completely replace nitrogen fertilization and can reduce production costs. The aim of this study was to evaluate the response of cowpea cultivar BRS Guariba to inoculation with six strains of rhizobia (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 and BR 3262) in a field experiment conducted in the Southwest of Piauí. The experimental design was randomized blocks with eight treatments and four replicates, including the six cited strains and two uninoculated controls, one with mineral nitrogen (70 kg ha-1) and the other without mineral nitrogen. Nodulation, growth, yield, nitrogen accumulation in shoots and in grains and crude protein content in grains were evaluated. Strains under selection (UFLA 03-154 and UFLA 03-164) promoted yields that were higher compared to those obtained by strains authorized as inoculants (INPA 03-11B, BR 3267 and BR 3262). Inoculation with strains UFLA 03-84, UFLA 03-154 and UFLA 03-164 promoted yields equivalent to the control with mineral nitrogen (796.51 kg ha-1) and similar to the yield obtained with the control without mineral nitrogen and without inoculation, indicating efficient symbiosis of the indigenous rhizobia. UFLA 03-154 was better than the other treatments in terms of increased crude protein.

A interação do feijão-caupi com estirpes de rizóbio eficientes na fixação biológica de nitrogênio pode permitir o aumento da sua produtividade, sendo possível substituir totalmente a adubação nitrogenada e reduzir os custos de produção. Objetivou-se avaliar a resposta do feijão-caupi cultivar BRS Guariba à inoculação com seis estirpes de rizóbio (UFLA 03-164, UFLA 03-154, INPA 03-11B, UFLA 03-84, BR 3267 e BR 3262) em experimento conduzido em campo no Sudoeste do Piauí. O delineamento experimental foi em blocos casualizados com oito tratamentos e quatro repetições, sendo as seis estirpes citadas e dois controles não inoculados, um com nitrogênio mineral (70 kg ha-1) e outro sem nitrogênio mineral. Foram avaliados nodulação, crescimento, produtividade, acúmulo de nitrogênio na parte aérea e nos grãos e o teor de proteína bruta nos grãos. As estirpes em fase de seleção (UFLA 03-154 e UFLA 03-164) promoveram rendimento de grãos superiores aos obtidos pelas estirpes autorizadas como inoculantes (INPA 03-11B, BR 3267 e BR 3262). As inoculações com as estirpes UFLA 03-84, UFLA 03-154 e UFLA 03-164 proporcionam rendimento de grãos equivalentes ao controle com nitrogênio mineral (796,51 kg ha-1), porém, semelhantes ao rendimento obtido com o controle sem nitrogênio mineral e sem inoculação, indicando boa eficiência simbiótica das populações nativas de rizóbio. A UFLA 03-154 destacou-se dos demais tratamentos com relação ao aumento de proteína bruta.

Laranja-da-terra: potential citric fruit for Piauí State / Laranja-da-terra: fruta cítrica potencial para o Piauí

The work had as objecive the phisico-chemical caracterization of laranja-da-terra fruits. Five samples of 10 fruits were harvested in laranja-da-terra plants produced in home orchards of the municipality of Bom Jesus/PI and caracterized by evaluation of lenght and width, number of the seeds per fruits, weigth, soluble solids (SS), titulable acidity (TA), vitamin C and SS/AT ratio. Laranja-da-terra has good quality phisico-chemical and is a natural source of vitamin C with an average of 125.76 mg/100g of fresh fruit, low titratable acidity and high values of soluble solids and SS/AT ratio.

O trabalho teve como objetivo a caracterização físico-química de frutos de laranja-da-terra (Ctrius aurantium L). Cinco amostras de dez frutos cada foram colhidas em plantas de laranja-da-terra produzidos em pomares domésticos do município de Bom Jesus/PI e caracterizadas pela avaliação de diâmetro e altura, número de sementes por fruto, massa de frutos sólidos solúveis (SS), acidez titulavel (AT), vitamina C e relação SS/AT. A laranja-da-terra tem boas qualidades físico-quimicas e é uma fonte natural de vitamina C com media de 125,76 mg/100g de fruta fresca, com acidez baixa e elevados sólidos solúveis e ratio.