Yield,Yield Components,Soil Chemical Properties,Plant Physiology,and Phosphorus Use Efficiency in Soybean Genotypes

Expansion of soybean [Glycine max (L.) Merrill] cultivated in Brazil to regions with low fertility soils gave rise to studies on the possibility of obtaining highly productive cultivars with high nutrient use efficiency. An experiment in greenhouse conditions was conducted to assess phosphorus (P) use efficiency (PUE) by 13 soybean genotypes. The genotypes were grown in an Ustoxix Quartzipsamment with two P rates [0 (no P application) and 150 mg P kg^?1], whose source was monoammonium phosphate (MAP, P₂O₅ 44%). Shoot dry weight (SDW), grain yield (GY), grain harvest index (GHI), relative yield (RY), and physiological components (photosynthetic rate, stomatal conductance, respiratory rate, and internal CO₂ concentration) were influenced by soybean genotypes and P rates. Genotypes BMX Apolo RR, BRS 360RR, BRS 378RR, CD 219RR, DM 2302RR, TMG 7161RR, and Vtop RR were classified as non-efficient and non-responsive to P application, while BMX Potência RR, Vmax RR, FPS Solar RR, NA 5909RR, TMG 1066RR, and M 6210 IPRO were classified as efficient and responsive. Phosphorus application increased the values of physiological components, which was not observed for N, K, Ca, Mg, and S concentration in the leaves and grains. Soybean genotypes selection for increased P efficiency could help growers overcome the problem of soybean cultivation on new areas or degraded pastures.     

Variability on Yield,Nutritional Status,Soil Fertility,and Potassium-Use Efficiency by Soybean Cultivar in Acidic Soil

The use of cultivar with nutrient-use efficiency is an important strategy in the management of plant nutritional status, particularly potassium (K), because its high demand and the progressive impoverishment caused by the use of inadequate amounts cause frequent deficiency symptoms observed in soybean [Glycine max (L.) Merrill] crops. This study was conducted in greenhouse conditions in a completely randomized design with four replicates in an Typic Quartzipsamment soil aimed to assess the effect of applying two rates of K (50 and 200 mg kg^?1) on growth, shoot dry weight yield (SDWY) and seed yield (SY), nutritional status, yield components, and efficiency of K use in eleven cultivars of different characteristics and growth habits. The SDWY, SY, number of seeds per pod, number of pods, and estimated 100-seed weight showed significant interaction between cultivar and the K rates, with greater values at the rate 200 mg K kg^?1. Similarly, the concentration of nitrogen (N), phosphorus (P), K, calcium (Ca), magnesium (Mg), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in leaves and grains varied according to the K rates and in the cultivar. The most K-use efficient cultivars were BMX Magna RR, BRS 232, BRS 284, BRS 294RR, NA 5909RR, and Vmax RR, whereas FTS Campo Mourão RR was inefficient. Regarding response to fertilization, the cultivars Vmax RR, BMX Magna RR, NA 5909RR, BRS 284, and BRS 294RR were found to be efficient and responsive, whereas the cultivar FTS Campo Mourão RR, BRS 232, BMX Potência RR, BRS 295RR, TMG 1066RR, and TMG 1067RR are inefficient and responsive to K application in the soil.     

Lime and Micronutrients Interaction in Soybean Genotypes Adapted to Tropical and Subtropical Conditions

Liming reduces acidity neutralizes aluminum (Al³⁺) and manganese (Mn²⁺) toxicities and increases calcium (Ca²⁺) and magnesium (Mg²⁺) concentrations in many acid soils of the world. However, it reduces the availability of other cationic micronutrients that are essential for plant growth. Therefore, an experiment was conducted in greenhouse conditions for assessing the effects of higher lime rates in foliar and grain boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) concentrations of 15 soybean genotypes [Glycine max (L) Merrill]. The lime rates were calculated to raise base saturation (V) to 40 and 70%. The soybean genotypes were classified as efficient and moderately efficient in lime-use, the most efficient cultivar was BRS 295RR, and the least efficient was TMG 7161RR and BMX Força RR. The lime rates × genotypes interaction was significant for foliar Cu. The grain the interactions were significant for B, Cu, Fe, and Mn concentrations. Foliar and grain B, Cu, Fe, Mn, and Zn concentrations varied significantly among the genotypes. The Ca and Mg concentrations in the leaf, grain, and soil showed a positive correlation with foliar B concentrations and a negative correlation with leaf and grain Cu, Mn, and Zn concentrations.     

Sulfur Use Efficiency in Soybean Cultivars Adapted to Tropical and Subtropical Conditions

Sulfur (S) is an essential nutrient in crop plants and one of the components of amino acids (AAs) and proteins. Studies about sulfur efficiency on soybean cultivars [Glycine max (L) Merril] adapted to the tropical and subtropical conditions are still incipient. In Brazil, one experiment under greenhouse conditions evaluated the S-efficiency from eight soybean cultivars. The plants cultivated in a Typic Quartzipsamment received two S rates (0 and 80 mg kg^?1). The grain yield (GY), shoot dry weight (SDW), and the relative yield (RY) had influence from the S rates. The cultivars BRS 295RR and BRS 360RR were the most efficient in using the S application. The number of pods per plant (NPP), photosynthetic rate (A), nitrate reductase (N-NO₂^?), and chlorophyll significantly increased with de 80 mg kg^?1 of S. By contrast, the internal concentration of carbon dioxide (CO₂) (Ci) was reduced. Similarly, there were increases in the concentration of nitrogen (N), phosphorus (P), magnesium (Mg), and N:S ratio in the leaves and grain, but the K increased only in the leaves. Comparing the cultivars, only the N concentration in the leaves and the Mg in the grain had non-significant differences.     

Upland Rice Genotype Evaluations for Acidity Tolerance

Upland rice is an important crop in South American cropping systems. In Brazil it is mainly grown in the central area, locally known as the Cerrado region. Soils of the Cerrado region are acidic and have poor fertility. A greenhouse experiment was conducted with the objective to evaluate thirty upland rice genotypes for acidity tolerance. Two acidity levels were created: high (without lime addition) and low (addition of 2.5 g dolomitic lime per kg soil). Plant height, straw yield, grain yield, panicle number, thousand-grain weight, spikelet sterility, grain harvest index (GHI), maximum root length, and root dry weight were significantly influenced by lime and genotype treatments. Lime × genotype interactions were also significant for most of these traits, indicating variation in these treats with the variation in acidity levels. Based on grain yield acidity tolerance index (GYATI), genotypes were classified as tolerant, moderately tolerant, and susceptible to soil acidity. Among thirty genotypes, 30 percent were classified as tolerant, 53 percent were classified as moderately tolerant, and 17 percent were classified as susceptible to soil acidity. Most of the growth, yield, and yield components had significant quadratic positive association with grain yield across two acidity levels. Soil acidity indices such as pH, base saturation, calcium (Ca) saturation, magnesium (Mg) saturation, and potassium (K) saturation increased with the addition of lime. Phosphorus content also increased with the addition of lime. However, hydrogen and aluminum (H + Al) and iron (Fe) content decreased with the addition of lime. Adequate soil acidity indices for grain yield were established.     

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 cmol_c kg^?1, Mg 0.9 cmol_c kg^?1, base saturation 51%, cation exchange capacity (CEC) 4.8 cmol_c kg^?1, Ca/Mg ratio 1.9, Ca?/?potassium (K) ratio 5.6, and Mg/K ratio 3.0.     

Optimum Soil Acidity Indices for Dry Bean Production on an Oxisol in No‐Tillage System

Abstract

Soil acidity is one of the major yield constraints to crop production in various parts of the world. Quantifying optimum soil acidity indices is an important strategy for achieving maximum economic crop yields on acid soils. Five field experiments were conducted for three consecutive years using dry bean as a test crop on an Oxisol. The lime rates used were 0, 12, and 24 Mg ha^?1 for creating a wide range of soil acidity indices in a no‐tillage cropping system. Grain yield of dry bean was significantly increased by improving soil pH, base saturation, calcium (Ca), magnesium (Mg), and potassium (K) saturation and reducing aluminum (Al) saturation. These soil acidity indices were higher in the 0‐ to 10‐cm soil layer than the 10‐ to 20‐cm soil layer for maximum grain yield. Across two soil depths, optimum values for maximum bean yield were pH 6.5, base saturation 67%, Ca saturation 48%, and Mg saturation 19%. Bean yield linearly increased with increasing K saturation in the range of 1.5 to 3% across two soil depths. There was a significant linear decrease in grain yield with increasing Al saturation in the range of 0 to 8% across two soil depths. Optimal values of soil indices for maximum bean yield can be used as a reference for liming and improving yield of bean crop on Oxisols in a no‐tillage cropping system. Yield components, such as pod number, grain per pod, and 100‐grain weight were significantly improved with liming, and bean yield was significantly associated with these yield components.     

Dry Bean Genotypes Evaluation for Zinc-Use Efficiency

Dry bean is an important legume for human consumption worldwide. Low soil fertility, including zinc (Zn) deficiency, is one of the main factors limiting yield of this legume in South America, including Brazil. The objective of this study was to evaluate 30 dry bean genotypes for zinc (Zn)–use efficiency. The Zn rates used were 0 mg Zn kg^?1 (low) and 20 mg Zn kg^?1 (high) of soil. Grain yield, straw yield, number of pods, hundred-seed weight, number of seeds per pod, maximum root length, and rood dry weight were significantly affected by Zn and genotype treatments. The Zn × genotype interactions were also significant for growth, yield, and yield components, indicating that some genotypes were highly responsive to the Zn application while others were not. Based on seed yield efficiency index (SYEI), genotypes were classified as efficient, moderately efficient, and inefficient in Zn-use efficiency. Most efficient genotypes were CNFP 10104, BRS Agreste, BRS 7762 Supreme, CNFC 10429, BRS Estilo, CNFC 10467, BRS Esplendor, and BRS Pitamaba. The most inefficient genotype was BRS Executive. Remaining genotypes were moderately efficient in Zn-use efficiency.     

Iron and manganese effect on soil chemical properties,yield components,and nutritional status of soybean

In plants, iron (Fe) and manganese (Mn) have many functions, as the transport and electron transference during photosynthesis, and their deficiencies affect the chlorophyll formation, plant growth and grain yield (GY). We carried out two experiments under greenhouse conditions with the aim of determining the influence of Fe and Mn on nutritional status, physiological components, soil chemical properties and yield components of soybean plants. In both experiments, five Fe and Mn rates were used. The GY, shoot dry weight yield (SDWY), the number of grain per pot (NGP), photosynthesis rate (A) and chlorophyll content were influenced by Fe rates, while GY, SDWY, root length and A were influenced by Mn rates. Iron and Mn concentrations in leaves and grains increased with rates of Fe and nutrients. The Mehlich 1 and DTPA-TEA extractants were efficient to determine the Fe and Mn available in the soil.     

Response of common bean varieties to the magnesium application in the tropical soil

The appropriate supply of magnesium (Mg) to the common bean (Phaseolus vulgaris L.) according to the requirements of each variety increases the productivity and nutritional value of grains. However, there are few studies on soil's ability to provide the adequate amount of the nutrient and on the reaction of plants with different Mg concentrations. The present study analyzed the response of the common bean plant to soil fertility, grain yield (GY), shoot dry weight (SDW) yield, nutritional status and the response of physiological components of the plant to the concentrations of Mg applied to the tropical soil. Thus, an experiment was conducted in a completely randomized design, in 5 × 4 factorial arrangement, with three replicates. The varieties BRS Estilo, IAPAR 81, BRS Ametista, IPR Campos Gerais (CG) and IPR Tangará were cultivated in an Ustoxix Quatzipsamment with five rates of Mg [0, 50, 100, and 200 mg kg^?1, source magnesium chloride (MgCl₂)]. The common bean varieties and the Mg rates significantly affected the soil chemical properties. Photosynthetic rate, stomatal conductance, transpiration rate, intercellular concentration of carbon dioxide (CO₂), and total soluble sugars significantly correlated with common bean GY and SDW yield. The nutrient content in leaves and grains showed difference responses among the varieties. IAPAR 81 showed the highest rate of mobilization of nitrogen, phosphorus, magnesium, sulfur, boron, copper and zinc (N, P, Mg, S, B, Cu, and Zn) for grains, being an important factor in studies of crop biofortification.     

Differential Soil Acidity Tolerance of Dry Bean Genotypes

Soil acidity is a major yield-limiting factors for bean production in the tropical regions. Using soil acidity–tolerant genotypes is an important strategy in improving bean yields and reducing cost of production. A greenhouse experiment was conducted with the objective of evaluating 20 dry bean genotypes for their tolerance to soil acidity constraints. An Inceptisol soil was amended with dolomitic lime (2 g dolomitic lime kg^–1 soil) to achieve low acidity (pH = 5.9) and without lime (zero lime kg^–1 soil,) to achieve high acidity (pH = 4.8) levels to evaluate bean genotypes. At both acidity levels, genotypes differed significantly in shoot dry weight and grain yield. Shoot dry weight and grain yield were significantly decreased at the high acidity level compared to the low acidity level. Grain yield was more sensitive to soil acidity than shoot dry weight. Hence, grain yield was used in determination of tolerance index (GTI) to differentiate the range of soil acidity tolerance among bean genotypes. Based on a GTI value, 55% of the genotypes were classified as tolerant, 40% classified as moderately tolerant, and the remaining were grouped as susceptible to soil acidity. The genotype CNFC 10410 was most tolerant and genotype CNFP 10120 was most susceptible to soil acidity. Number of pods and grain harvest index were significantly and positively associated with grain yield. The improvement in grain yield in low acidity may be related to reduction of toxic levels of soil aluminum (Al³⁺) and hydrogen (H⁺) ions by lime addition. At harvest, soil extractable phosphorus (P) and potassium (K) increased with the reduction of soil acidity, and this might have contributed to the better nutrition of beans and lead to higher growth.     

Boron and Amino Acid Foliar Application on Wheat-Soybean Intercropping in a Non-Tillage System

Micronutrient and amino acid (AA) foliar fertilization has generally been sprayed onto plants to increase the crop yield. The experiment had the aim of evaluating the foliar boron (B) and AA application on grain yield (GY), physiological characteristics, nutritional status, and yield components in wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merrill] intercropping in a non-tillage system (NTS). The experiment was set up as a randomized block design with eight treatments and four replicates. The treatments had the following boron (B) rates: [0, 1, 2, 4, and 8 kg ha^?1, source: boric acid (H₃BO₃)] + AAs (2 L ha^?1) applied by foliar spraying and the additional treatments [(Control - without B and AAs), 2 kg ha^?1 B, 2 L ha^?1 AAs and 2 kg ha^?1 B + 1 L ha^?1 AAs] applied at the end of the elongation and spike beginning of wheat plants and development growth stage (V5) of soybean for two growing seasons. Boron and AAs had no influence on the physiological and yield components and had no increases in the foliar and grain B content in wheat and soybean. No matter the dose, the foliar B + AAs (2 L ha^?1) application did not increase the GY in wheat-soybean under a rotational NTS in loamy soil with suitable available B.     

Lowland Rice Genotypes Evaluation for Potassium-Use Efficiency

Lowland rice significantly contributes to world as well as Brazilian rice production and information on genotypes potassium-use efficiency is limited. A greenhouse experiment was conducted with the objective to evaluate lowland rice genotypes for potassium (K)–use efficiency. Ten genotypes were evaluated at 0 mg K kg^?1 (low) and 200 mg K kg^?1 (high) of soil. Grain yield and shoot dry weight were significantly affected by K as well as genotype treatments. Genotypes CNAi 8860, CNAi 8859, BRS Fronteira, and BRS Alvorada were the best in relation to K-use efficiency because they produced best grain yield at low as well as at higher K levels. Shoot dry weight, number of panicles per pot, and 1000-grain weight had highly significant (P < 0.01) association with grain yield. Spikelet sterility, however, had significant negative association with grain yield. These plant parameters were mainly influenced by genotypes, indicating importance of selecting appropriate genetic material for improving grain yield. Soil K depletion was significant at harvest, suggesting large amount of K uptake by lowland rice genotypes.     

NITROGEN USE EFFICIENCY IN DRY BEAN GENOTYPES

Dry bean is an important legume crop for Latin American people and nitrogen is one of the most yields limiting nutrients for bean crop. A greenhouse experiment was conducted to evaluate nitrogen (N) use efficiency of 20 dry bean genotypes. Genotypes were grown on an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg^?1 (high level). Shoot dry weight, grain yield and yield components, N concentration and uptake in shoot and grain were significantly affected by N and genotype treatments. Grain yield had a highly significant (P < 0.01) association with shoot dry weight, pod number, grains per pod and 100 grain weight. Among the 20 genotypes tested, Perola, CNFR 7847, CNFR 7865, CNFP 7777 and CNFM 6911 were found to produce reasonably good yield at low N rate as well as responded well to applied N. Whereas, some genotypes like BRS Radiante, CNFP 7624, CNFM 7875, CNFM 7886, CNFC 7813, CNFC 7827, CNFP 7677 and CNFP 7775 produced very good yields at higher N rate but very low yields at lower N rate. Hence, these genotypes are good for farmers using higher technology. Nitrogen concentration and uptake were higher in dry bean grains compared with shoot and 63% of N accumulated at zero N rate and 75% N accumulated at 400 mg N rate were translocated to grain across 20 genotypes. Nitrogen uptake efficiencies were having highly significant (P < 0.01) quadratic relationship with grain yield. This indicates that improving N uptake in dry bean plants can increase grain yield.     

Influence of pH on Productivity,Nutrient Use Efficiency by Dry Bean,and Soil Phosphorus Availability in a No‐Tillage System

Abstract

Low pH is one of the most yield‐limiting factors for crop production in Cerrado soils. The objective of this study was to determine influence of soil pH on grain yield and its components, and use of nutrients by dry bean in a no‐tillage system in an Oxisol (Typic Haplorthox) of the Cerrado region of Brazil. Five field experiments were conducted for three consecutive years. The pH levels were low (5.3), medium (6.4), and high (6.8), created by applying lime at the rates of 0, 12, and 24 Mg ha^?1. Grain yield and its components were significantly influenced by soil pH. Adequate pH for grain yield and its components was 6.4. Maximum variation in grain yield was measured by shoot dry weight, and minimum variation was due to 100‐grain weight. Nutrient utilization efficiency was in the order of magnesium (Mg) > phosphorus (P) > calcium (Ca) > potassium (K) > nitrogen (N) > copper (Cu) > manganese (Mn) > zinc (Zn) > iron (Fe). Soil extractable P increased linearly with increasing pH in the range of 5.3 to 7.3. These results show that adequate soil pH is an important soil acidity index in improving bean yield in Brazilian Oxisols.     

Nitrogen-Use Efficiency in Lowland Rice Genotypes under Field Conditions

Rice is staple food for more than 50% of the world's population. Nitrogen (N) is one of the most yield-limiting nutrients for lowland rice production around the world. Two field experiments were conducted at two locations for two consecutive years to evaluate N-use efficiency of 12 lowland rice genotypes. Growth, grain yield, and yield components were significantly influenced by N as well as genotype treatments. Location?×?year?×?genotype and location?×?year?×?N interactions were significant for most of the growth, yield, and yield components, indicating influence of these factors on yield and yield components. Overall, the most N-efficient genotypes measured in terms of grain yield were BRA 031032, BRA 031044, and BRA 02654 and the most inefficient genotypes were BRS Jaçana, BRS Fronteira, and BRA 02674. Genotypes had linear and quadratic responses to added N in the range of 0 to 200 kg ha^?1. Nitrogen significantly influenced plant height, shoot dry weight, panicle number, and 1000-grain weights. Nitrogen-use efficiency (kg grain per kg N applied) varied from 33 to 49 kg grain per kg N applied, with an average value of 40 kg grain per kg N applied. The genotype BRA 031044 produced the greatest N-use efficiency, and the lowest N-use efficient genotype was BRS Fronteira. There was a significant linear association between N-use efficiency and grain yield.     

Lowland Rice Genotypes Evaluation for Nitrogen Use Efficiency

Rice is important crop for world population, including Brazil. Nitrogen (N) is one of the most yield limiting nutrients in rice production under all agro-ecological conditions. A greenhouse experiment was conducted to evaluate N responses to 12 lowland rice genotypes. Soil used in the experiment was a Gley humic according to Brazilian soil classification system and Inceptisol according to USA soil taxonomy classification. The N rates used were 0 mg kg^?1 (low) and 300 mg kg^?1 (high) of soil. Plant height, straw yield, grain yield, panicle density, 1000 grain weight, and root dry weight were significantly increased with the addition of N fertilization. These growth, yield, and yield components were also significantly influenced by genotype treatment. Grain yield had significant linear or quadratic association with shoot dry weight, panicle number and 1000 grain weight Based on grain efficiency index genotypes were classified as efficient, moderately efficient and inefficient in N use. The N efficient genotypes were ‘BRS Tropical’, ‘BRS Jaçanã’, ‘BRA 02654’, ‘BRA 051077’, ‘BRA 051083’, ‘BRA 051108’, ‘BRA 051130’ and ‘BRA 051250’. Remaining genotypes fall into moderately efficient group. None of the genotypes were grouped as inefficient in N use efficiency.     

LOWLAND RICE GENOTYPES EVALUATION FOR PHOSPHORUS USE EFFICIENCY IN TROPICAL LOWLAND

Lowland rice is a staple food for more than 50% of the world's population and phosphorus (P) deficiency is one of the main constraints in rice production in tropical lowlands. A field experiment was conducted for two years consecutive with the objective to evaluate 12 lowland rice genotypes for P use efficiency. The P rates used were 0, 22, 44, 66, and 88 kg P ha^?1 (0, 50, 100, 150 and 200 kg P₂O₅ ha^?1) applied to an Inceptisol. The genotypes used were BRS Jaçanã, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guará, BRS Alvorada, BRS Jaburu and BRS Biguá. There were significant and quadratic responses of genotypes to phosphorus fertilization. Adequate P rates for maximum grain yield varied from genotype to genotype. However, across 12 genotypes, maximum grain yield was obtained with the application of 54 kg P ha^?1. Genotype BRS Jaçanã was most efficient and genotype CNAi 8569 was most inefficient in P use efficiency. Shoot dry weight and panicle number was also increased significantly and quadratically with increasing P rates in the range of 0 to 88 kg P ha^?1. These two plant parameters were positively associated with grain yield. Agronomic efficiency (kg grain produced per kg P applied) was significantly decreased with increasing P rates in the range of 22 to 88 kg P ha^?1.     

UPLAND RICE GENOTYPES EVALUATION FOR PHOSPHORUS USE EFFICIENCY

Phosphorus (P) deficiency is one of the most yield limiting factors in crop production in Brazilian Oxisols. A greenhouse experiment was conducted to evaluate 20 upland rice genotypes at low (25 mg P kg^?1) and high (200 mg P kg^?1) P levels applied to a Brazilian Oxisol. Grain yield and yield components were significantly influenced by P level and genotype treatments. There was a significant interaction between P level and genotype treatments in relation to grain yield, indicating genotypes responded differently under two P levels. Based on grain yield efficiency index (GYEI), genotypes were classified into efficient, moderately efficient and inefficient groups. The efficient genotypes in utilizing P were ‘BRA052053’, ‘BRS Primavera’, ‘BRA052015’, ‘BRA052023’, ‘BRA01506’, ‘BRA052045’, ‘BRA032033’, ‘BRA01596’ and ‘BRA052034’. Remaining genotypes were classified as moderately efficient in P use efficiency. None of the genotypes were fall into inefficient group. Grain yield was significantly and positively related with shoot dry weight, panicle number, grain harvest index, 1000-grain weight and had a negative and significant correlation with spikelet sterility. Grain weight was having maximum contribution in total rice plant weight comparing to root and shoot, indicating improvement in harvest index of modern Brazilian upland rice cultivars by breeding.     

Corrective Potential of Alkaline Residue (Dregs) from Cellulose Industry in an Acid Soil Cultivated Under No-tillage

The use of alkaline residues from cellulose industry can increase soil fertility and crop productivity, but some of these residues, such as dregs, can also reduce soil physical quality. This study aimed to evaluate the effects of the dregs compared to lime as corrective for soil acidity applied on the surface under no-tillage. The treatments applied, half in 2004 and half in 2006, were: without corrective; dregs rates of 3.25, 6.5 and 13 Mg ha^?1 and dolomitic lime rates of 5.25 and 10.5 Mg ha^?1. After 5.5 years since the first application, soil chemical and physical attributes were determined, as well as soybean yield in 2010 and bean yield in 2011. Positive effects were observed on the soil chemical attributes with the application of dregs or lime, such as increased pH, calcium content, cation exchange capacity, and base saturation, and decreased the aluminum saturation. However, it was observed increase in sodium content and calcium/magnesium ratio with the application of dregs, however without impairing the soil physical quality. The soybean and bean yield increased in a similar way using dregs or lime. These results indicate the possibility of using dregs as corrective of soil acidity.