Milton Ferreira Moraes

Influence of Lime and Gypsum on Yield and Yield Components of Soybean and Changes in Soil Chemical Properties

Soybean is one of the most important legume crops in the world. Two greenhouse experiments were conducted to determine the influence of liming and gypsum application on yield and yield components of soybean and changes in soil chemical properties of an Oxisol. Lime rates used were 0, 0.71, 1.42, 2.14, 2.85, and 4.28 g kg−1 soil. Gypsum rates applied were 0, 0.28, 0.57, 1.14, 1.71, and 2.28 g kg−1 soil. Lime as well as gypsum significantly increased grain yield in a quadratic fashion. Maximum grain yield was achieved with the application of 1.57 g lime per kg soil, whereas the gypsum requirement for maximum grain yield was 1.43 g per kg of soil. Lime significantly improved soil pH, exchangeable soil calcium (Ca) and magnesium (Mg) contents, base saturation, and effective cation exchange capacity (ECEC). However, lime application significantly decreased total acidity [hydrogen (H) + aluminum (Al)], zinc (Zn), and iron (Fe) contents of the soil. The decrease in these soil properties was associated with increase in soil pH. Gypsum application significantly increased exchangeable soil Ca, base saturation, and ECEC. However, gypsum did not change pH and total acidity (H + Al) significantly. Adequate soil acidity indices established for maximum grain yield with the application of lime were pH 5.5, Ca 1.8 cmolc kg−1, Mg 0.66 cmolc kg−1, base saturation 53%, Ca saturation 35%, and Mg saturation 13%. Soybean plants tolerated acidity (H + Al) up to 2.26 cmolc kg−1 soil. In the case of gypsum, maximum grain yield was obtained at exchangeable Ca content of 2.12 cmolc kg−1, base saturation of 56%, and Ca saturation of 41%.

Optimal Acidity Indices for Soybean Production in Brazilian Oxisols

Soybean is an important crop for the Brazilian economy, and soil acidity is one of the main yield-limiting factors in Brazilian Oxisols. A field experiment was conducted during three consecutive years with the objective to determine soybean response to liming grown on Oxisols. Liming rates used were 0, 3, 6, 12, and 18 Mg ha−1. Liming significantly increased grain yield in a quadratic trend. Ninety percent maximum economic grain yield (2900 kg ha−1) was achieved with the application of about 6 Mg lime ha−1. Shoot dry weight, number of pods per plant, and 100-grain weight were also increased significantly in a quadratic fashion with increasing liming rate from 0 to 18 Mg ha−1. These growth and yield components had a significant positive association with grain yield. Maximum contribution in increasing grain yield was of number of pods per plant followed by grain harvest index and shoot dry weight. Uptake of nitrogen (N) was greatest and phosphorus (P) was least among macronutrients in soybean plant. Nutrient-use efficiency (kg grain per kg nutrient accumulation in grain) was maximum for magnesium (Mg) and lowest for N among macronutrients. Application of 3 Mg lime ha−1 neutralized all aluminum ions in soil solution. Optimal acidity indices for 90% of maximum yield were pH 6.0, calcium (Ca) 1.6 cmolc kg−1, Mg 0.9 cmolc kg−1, base saturation 51%, cation exchange capacity (CEC) 4.8 cmolc kg−1, Ca/Mg ratio 1.9, Ca / potassium (K) ratio 5.6, and Mg/K ratio 3.0.

Nitrogen Uptake and Use Efficiency in Upland Rice under Two Nitrogen Sources

Upland rice is an important crop in South America, including Brazil. Nitrogen (N) is one of the most yield-limiting nutrients in upland rice production in Brazil. A greenhouse experiment was conducted to evaluate N uptake and use efficiency as influenced by N sources. The soil used in the experiment was an Oxisol. The N sources were ammonium sulfate and urea, and N rates were 0, 50, 100, 150, 300, and 400 mg kg−1 of soil. Nitrogen concentrations in the root, shoot, and grain were significantly influenced by N sources. The N rate and N source significantly influenced the N uptake in root, shoot, and grain. Similarly, nitrogen rate by N source interaction was also significant for N uptake in the root, shoot, and grain, indicating N source has a significant influence on uptake of N. Overall, concentration (content per unit dry weight) of N was greater in the grain, followed by root and shoot. Agronomical efficiency, apparent recovery efficiency, and utilization efficiency of N were significantly influenced by N rate and varied with N sources. However, physiological and agrophysiological efficiencies were only influenced significantly by N sources. Overall, N recovery efficiency was 33% for ammonium sulfate and 37% for urea. Hence, the large amount of N lost from soil–plant system may be by denitrification or voltilization.

Phosphorus Nutrition of Lowland Rice in Tropical Lowland Soil

Rice is a main food crop for about half of the worlds population, and phosphorus (P) is the main limiting nutrient in rice production in tropical lowlands. A greenhouse experiment was conducted to evaluate P requirements of lowland rice grown on a lowland soil (Inceptisol). Dry matter, grain yield, and yield-attributing characteristics were significantly (P < 0.01) influenced by P fertilization. Based on quadratic response, maximum shoot dry weight and grain yield were obtained with the application of 190 mg P kg−1 of soil. Maximum panicle, tiller number, and plant height were obtained with the application of 177 192, and 175 mg P kg−1 of soil, respectively. Mehlich 1–extractable P for maximum grain yield was 15.6 mg kg−1 of soil. Variability in grain yield with plant growth and yield parameters was in the order of tiller > shoot dry weight > panicle number > spikelet sterility > plant height > grain harvest index > panicle length > weight of 1000 grains. Phosphorus uptake in shoot and concentration and uptake in grain significantly (P < 0.01) increased grain yield. However, variability in grain yield was greater with concentration and uptake of P in the grain. Similarly, P harvest index was also significantly associated with grain yield. Agronomic P-use efficiency, apparent P-recovery efficiency, and P-utilization efficiency decreased quadratically with increasing P rates, whereas physiological P-use efficiency increased quadratically and agrophysiological P-use efficiency decreased linearly with increasing P rates. Agrophysiological and utilization P-use efficiencies had significant positive correlation with grain yield.

Nutrient Uptake and Use Efficiency of Dry Bean in Tropical Lowland Soil

Dry bean is an important source of protein for the population of South America, and yield of this legume is very low in this continent. Knowledge of nutrient uptake and use efficiency of a crop is fundamental to improve yield. A greenhouse experiment was conducted to evaluate growth, nutrient uptake, and use efficiency of dry bean (Phaseolus vulgaris L., cv. BRS Valente) during the growth cycle. Plant samples were collected at 15, 30, 45, 60, 73, and 94 days after sowing. Root dry weight, maximum root length, shoot dry weight, and number of trifoliates were significantly increased in a quadratic fashion with the advancement of plant age. Root dry weight and number of trifoliates had significant positive association with shoot dry weight. Uptake of nutrients in the grain was in the order of nitrogen (N) > potassium (K) > calcium (Ca) > magnesium (Mg) > phosphorus (P) > iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Hence, it can be concluded the N requirements for bean is greatest and Cu is minimal compared to other essential nutrients for grain yield. Uptake efficiency for root, shoot, and grain production was in the order of P > Mg > Ca > K > N > Cu > Zn > Mn > Fe. The greatest P-use efficiency among macro- and micronutrients can be considered a positive aspect of mineral nutrition of bean, because recovery efficiency of P in acidic Inceptsols is less than 20%.

Humic Substances on Soybeans Grown Under Water Stress

ABSTRACT Hypothetically, humic substances (HSs) can improve the response of plants in sandy soils. The objective was to assess the effect of applying an organomineral fertilizer enriched with HSs on soybean plants grown with and without water stress. The experimental design was entirely randomized, in a greenhouse, in a 2 × 5 factorial setup (two moisture levels and five fertilizer doses: 0, 1, 2, 4, and 8 mL dm−3), for a total of 10 treatments, with eight repetitions, using as substrate a Psamment. The organomineral fertilizer was applied in the soil 21 days after plant emergence, and the water regimes were established 1 week thereafter. Plant height, shoot and root dry mass, mineral nutrition, and grain yield were evaluated. There was a positive response to the doses, with the most efficient one under water stress being 6.5 mL dm−3 and HSs favored the uptake of micronutrients.

Grain zinc concentrations differ among Brazilian wheat genotypes and respond to zinc and nitrogen supply

The combined application of nitrogen (N) and zinc (Zn) fertilizers is a promising agronomic strategy for the biofortification of wheat grain with Zn for human nutrition. A glasshouse experiment was carried out to assess the effects of supplying N on the uptake, translocation and accumulation of Zn in tissues of two wheat genotypes (Quartzo and BRS Parrudo) with contrasting potential for grain Zn biofortification. Winter wheat genotypes were grown to maturity in 5 cm diameter, 100 cm length tubes filled with a mixture of sand, grit and gravel (40:40:20 v/v/v) over a layer of 0.1 m3 of gravel, and supplied a full nutrient solution with low Zn (0.15 μM) or high Zn (2.25 μM) and low N (0.4 mM) or high N (4.0 mM) concentrations. High N supply increased biomass production, Zn concentration and Zn content of straw and grain in both Quartzo and BRS Parrudo. Grain Zn content more than doubled when the supplies of Zn and N were both increased from low to high in both genotypes. Quartzo had a greater grain yield than BRS Parrudo. BRS Parrudo had greater grain Zn concentration and Zn content than Quartzo. A greater N supply promoted better uptake, translocation to the shoot and accumulation of Zn within the grain. Quartzo and BRS Parrudo differed in their partitioning of biomass and Zn between tissues. It might be possible to combine the greater grain yield of Quartzo with the greater grain Zn accumulation of BRS Parrudo to deliver a greatly improved genotype for human food security.

Liquid organomineral fertilizer containing humic substances on soybean grown under water stress

Fertilizante organomineral líquido contendo substâncias húmicas em soja cultivada sob estresse hídrico R E S U M O Avaliou-se, neste trabalho, o efeito de um fertilizante organomineral enriquecido com substâncias húmicas em soja submetida a estresse hídrico. Em casa de vegetação foi realizado um experimento utilizando-se, como substrato, um Latossolo Vermelho com nível de fertilidade adequado no qual foram cultivadas plantas de soja em duas condições, sem e com estresse hídrico. O delineamento foi em blocos casualizados em esquema fatorial 2 x 5 (dois níveis de umidade e cinco doses: 0, 1, 2, 4 e 8 mL dm-3) totalizando 10 tratamentos, com 4 repetições. O fertilizante organomineral foi aplicado ao solo 21 dias após a emergência das plantas estabelecendo-se, uma semana após sua aplicação, os níveis de umidade. O fertilizante organomineral não foi capaz de atenuar os efeitos adversos do estresse hídrico reduzindo a produtividade dos grãos de soja em mais de 50% quando comparado às plantas cultivadas sem estresse hídrico. Houve resposta positiva quanto às doses sobre a nutrição e produtividade de grãos sendo que, na condição de estresse hídrico, a mais eficiente foi 5,4 mL dm-3; foi menor a concentração foliar de nitrogênio, fósforo e potássio nas plantas com estresse e maior concentração de enxofre; as substâncias húmicas favorecem a absorção de micronutrientes.