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Rice (Oryza sativa L.) is the staple food for more than 50% world population and nitrogen (N) is one of the most yield-limiting nutrients for rice production worldwide. A greenhouse experiment was conducted to evaluate the efficiency of three N sources for lowland rice production. The N sources used were ammonium sulfate, common urea, and polymer-coated urea. There were three N rates, i.e. 100, 200, and 400 mg N kg−1 applied with three sources plus one control treatment (0 mg N kg−1). Growth, yield, and yield components were significantly increased either in a linear or quadratic fashion with the addition of N fertilizers in the range of 0–400 mg kg−1 soil. Maximum grain yield was obtained with the addition of ammonium sulfate at 100, 200, and 400 mg kg−1 of soil. Common urea and polymer-coated urea were more or less similar in grain production at 100 and 200 mg N kg−1. However, at 400 mg N kg−1 treatments, polymer-coated urea produced the lowest grain yield. Most of the growth and yield component...

Globally, lowland rice contributes more than 70 percent of total rice production, and nitrogen (N) is one of the most yield-limiting nutrients for lowland rice production under all agroecological conditions. A field experiment was conducted for 2 consecutive years to evaluate response of twelve lowland rice genotypes to N fertilization. The N rates used were 0, 50, 100, 150, and 200 kg ha−1. Plant height, grain yield, panicle number, 1000-grain weight, spikelet sterility, grain harvest index (GHI), and nitrogen-use efficiency (NUE; grain yield per unit of N applied) were significantly influenced by N and genotype treatments, except for 1000-grain weight and spikelet sterility, which were not affected by N treatment. Across N rates, genotypes BRS Tropical, BRA 051126, BRA 051130, BRA 05108, and BRA 051134 produced greater grain yields (above average of twelve genotypes) and genotypes BRS Jacana, BRA 02654, BRA 051077, BRA 051108, BRA 051129, BRA 051135, and BRA 051250 produced lower grain yield (lower tha...

Rice is a staple food for more than 50 percent world’s population. It is mainly grown under two ecosystems, known as upland and lowland. Soils on which these two types of rice are grown are mostly deficient in phosphorus (P). Two field experiments were conducted (one with upland rice and another with lowland rice) with the objective to determine responses of upland and lowland rice to two sources of P fertilizers. The P sources were mono-ammonium phosphate and polymer coated mono-ammonium phosphate. The P rates used in the two experiments were 25, 50, 100, and 200 kg P2O5 ha−1 plus one control treatment. Plant height and grain yield of upland rice significantly increased with the addition of P fertilization. Similarly, plant height, straw yield, grain yield, panicle density, 1000-grain weight, P concentration, and uptake of lowland rice were significantly increased with the application of P fertilization. The response of these plant parameters to P fertilization was quadratic in nature. Rate of P for maxi...

Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20 mg kg−1. In one experiment dolomitic lime was added at the rate of 2.5 g per kg of soil before the application of Mo treatments and incubated 5 weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20 mg kg−1. Maximum shoot dry weight was obtained with the addition of 17 mg Mo kg−1 in the experiment with Mo rates without lime and 9.69 mg Mo kg−1 in the experimen...

Phosphorus (P) deficiency is one of the most yield-limiting factors in lowland rice production on Brazilian Inceptisol. The objective of this study was to evaluate eight P sources for lowland rice production. The P sources were simple superphosphate (SSP), polymer-coated simple superphosphate (PSSP), ammoniated simple superphosphate (ASSP), polymer-coated ammoniated simple superphosphate (PASSP), triple superphosphate (TSP), polymer-coated triple superphosphate (PTSP), monoammonium phosphate (MAP), and polymer-coated monoammonium phosphate (PMAP). These P sources were applied in four rates (i.e., 50, 100 200, and 400 mg P kg−1) + one control treatment (0 mg P kg−1). Plant height, straw yield, grain yield, panicle number, and root dry weight were significantly increased in a quadratic fashion with increasing P levels from 0 to 400 mg kg−1 of all the P sources evaluated. However, overall maximum root length and P-use efficiency were significantly less at greater P levels. Based on regression equation, maxim...

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 genoty...

Lowland or flooded rice is mainly responsible for about 76% of total rice production at global level, yet information on micronutrient requirements for this crop is limited. Six greenhouse experiments were conducted at the National Rice and Bean Research Center of EMBRAPA, Santo Antonio de Goias, Brazil, to determine requirements of zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), manganese (Mn), and iron (Fe) for lowland rice grown on a Brazilian Inceptisol. The levels of micronutrients used were Zn (0, 10 20, 40, and 80 mg kg−1), Cu (0, 5, 10, 20, and 40 mg kg−1), B (0, 5, 10, 20, and 40 mg kg−1), Mo (0, 2, 4, 8, and 16 mg kg−1), Mn (0, 50, 100, 300, and 600 mg kg−1), and Fe (0, 250, 500, 1000, and 2000 mg kg−1). Grain yield was significantly increased in a quadratic fashion with the addition of Zn, Cu, B, Mo, Mn, and Fe. The adequate rates of micronutrients for maximum grain yield were Zn 33 mg kg−1, Cu 25 mg kg−1, B 26 mg kg−1, Mo 10 mg kg−1, Mn 250 mg kg−1, and Fe 1269 mg kg−1. In addition to grai...

Rice is the staple food crop for about 50% of the world's population. It is grown mainly under two ecosystems, known as upland and lowland. Lowland rice contributes about 76% of the global rice production. The anaerobic soil environment created by flood irrigation of lowland rice brings several chemical changes in the rice rhizosphere that may influence growth and development and consequently yield. The main changes that occur in flooded or waterlogged rice soils are decreases in oxidation–reduction or redox potential and increases in iron (Fe2+) and manganese (Mn2+) concentrations because of the reductions of Fe3+ to Fe2+ and Mn4+ to Mn2+. The pH of acidic soils increased and alkaline soils decreased because of flooding. Other results are the reduction of nitrate (NO3 −) and nitrogen dioxide (NO2 −) to dinitrogen (N2) and nitrous oxide (N2O); reduction of sulfate (SO4 2−) to sulfide (S2−); reduction of carbon dioxide (CO2) to methane (CH4); improvement in the concentration and availability of phosphorus ...

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 Jacana, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guara, BRS Alvorada, BRS Jaburu and BRS Bigua. 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 Jacana was most efficient and genotype CNAi 8569 was most inefficient in P use efficiency. Shoot dry weight and panicle number was also inc...

Zinc (Zn) deficiency in annual crops is very common in Brazilian Oxisols. Data are limited on Zn uptake and use efficiency during crop growth cycles. A field experiment was conducted during two consecutive years with the objective to determine shoot dry weight and Zn uptake and use efficiency in upland rice, dry bean, corn, and soybean during growth cycles. Shoot dry weight of four crops was significantly increased in an exponential quadratic fashion with increasing plant age. Rice and corn had higher shoot dry weights and grain yields than dry bean and soybean. Zinc concentration in rice and corn decreased in a quadratic fashion with increasing plant age. However, in dry bean and soybean, Zn concentration had a quadratic increase. Zinc uptake followed an exponential quadratic response in four crops, and it was higher in corn and upland rice than in dry bean and soybean. Zinc use efficiency in shoot dry‐weight production had significant quadratic responses in upland rice and soybean with increasing plant ...

Lowland rice is a staple food for more than 50% world population. Iron toxicity is one of the main nutritional disorders, which limits yield of lowland rice in various parts of the world. The toxicity of iron is associated with reduced soil condition of submerged or flooded soils, which increases concentration and uptake of iron (Fe2 +). Higher concentration of Fe2 + in the rhizosphere also has antagonistic effects on the uptake of many essential nutrients and consequently yields reduction. In addition to reduced condition, increase in concentration of Fe2 + in submerged soils of lowland rice is associated with iron content of parent material, oxidation-reduction potential, soil pH, ionic concentration, fertility level, and lowland rice genotypes. Oxidation-reduction potential of highly reduced soil is in the range of –100 to –300 mV. Iron toxicity has been observed in flooded soils with a pH below 5.8 when aerobic and pH below 6.5 when anaerobic. Visual toxicity symptoms on plants, soil and plan...

Dry bean (Phaseolus vulgaris L.) is an important food legume for the world population. However, its average yield is low worldwide. The main reasons for low yield are biotic and abiotic stresses. Maximum economic yield of a crop can be achieved with appropriate balance between plant and environmental factors during crop growth cycle. Adopting appropriate management practices in favor of high yields can modify some of these factors. Hence, knowledge of yield physiology of dry bean is important for understanding yield formation components during crop growth and development and consequently improving yield. Dry bean growth cycle is divided into vegetative and reproductive growth stages. During vegetative stage, development of roots, trifoliate, node, and branches take place. Main features of reproductive growth stage are flowering, pod and grain formation. Important plant traits associated with yield are root and shoot dry matter yield, pod number, 100 grain weight, leaf area index, grain harvest in...

Rice is a staple food for more than 50% of the world's population and nitrogen (N) is one of the most yield limiting nutrients in lowland rice ecosystems. A field experiment was conducted for two consecutive years to evaluate dry matter production and grain yield of 12 lowland rice genotypes (BRS Jacana, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guara, BRS Alvorada, BRS Jaburu, and BRS Bigua) at five N rates (0, 50, 100, 150, and 200 kg ha− 1). Genotypes showed significant variation in grain yield and shoot dry weight. Genotype BRSGO Guara was highest yielding, whereas genotype BRS Jaburu was lowest yielding and the remaining genotypes were intermediate in grain yielding potential. Grain yield and shoot dry weight were having significant quadratic increase with increasing N rates in the range of 0 to 200 kg ha− 1. However, 90% of the maximum yield is often considered as an economical rate, which was 120 kg for shoot dry weight and 136 kg N ha− 1 for gr...

Use of adequate rates of phosphorus (P) in crop production on high‐P‐fixing acid soils is essential because of high crop response to P fertilization and the high cost of P fertilizers. Information on lowland rice response to thermophosphate fertilization grown on Inceptisols is limited, and data are also lacking for soil‐test‐based P fertilization recommendations for this crop. The objective of this study was to evaluate response of lowland rice to added thermophosphate and to calibrate P soil testing for making P fertilizer recommendations. A field experiment was conducted for two consecutive years in central Brazil on a Haplaquept Inceptisol. The broadcast P rates used were 0, 131, 262, 393, 524, and 655 kg P ha−1, applied as thermophosphate Yoorin. Rice yield and yield components were significantly increased with the application of P fertilizer. Average maximum grain yield was obtained with the application of 509 kg P ha−1. Uptake of macro‐ and micronutrients had significant quadratic response...

Rice is one of the world's most important cereal crops and rice ratooning is one of the potential technologies to increase rice production. Based on land and water management, rice ecosystem is mainly divided into lowland, upland and deep water or floating rice. Rice ratooning is mainly practiced on lowland rice ecosystem. Ratooning provides higher resource use efficiency per unit time and per unit land area. However, better yield of ratoon crop is possible by adopting appropriate management practices for main crop as well as for ratoon crop. These management practices include land preparation, adequate plant density and spacing, use of appropriate cultivars, water management, application of adequate rate of fertilizers, appropriate height of cutting, and control of diseases, insects and weeds.

Phosphorus (P) deficiency is the most yield-limiting factor in lowland rice production in Inceptisols of Brazil. A greenhouse experiment was conducted to evaluate 12 genotypes of lowland rice (Oryza sativa L.) using an Inceptisol (Typic Haplaquepts). The P treatments were: low (0 mg P kg−1), medium (100 mg P kg−1), and high (400 mg P kg−1). Significant (P

Aluminum (Al) toxicity is a major limiting factor for crop production in many acid soils in Brazil. Two greenhouse experiments were conducted to evaluate response of rice (Oryza saliva L.) and common bean (Phaseolus vulgaris L.) to Al levels on a Low Humic Gley acid soil. The Al levels created by liming were: 0,0.03, 0.10, 0.23, 1.03, and 3.83 cmolc kg‐1 of soil. Rice dry matter and grain yield were significantly improved (P