Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky. Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2). Results showed that cultivars used different physiological strategies to achieve high yields, but these were not always consistent across the environments studied. High yields were often associated to a higher efficiency partitioning biomass to seeds that lead to a higher seed number in some cultivars, as well as associated to low seed growth rates (Chapter 1). The choice of MG cultivar had a greater impact on double-crop soybean yields than increasing seeding rates from 40 to 54 seed m-2. The higher seeding rate increased yields by 5% without an interaction with cultivar. Optimal MG choices for double-crop soybean in KY were dependent on the environment.

Within Arkansas, Louisiana, Mississippi, Missouri, and Texas, rice acreage is rotated with soybean due to both crops’ adaptability to the clay soils of the midsouthern USA. Two row patterns, two maturity groups, and six seeding rates were examined at Stoneville, MS, in 2009-2010, with respect to soybean growth and yield produced on silt loam soil. Optimal yield for MG IV was 333,000 seed ha-1 (297,000 plants ha-1). Twin-row soybean increased seed yield 7 to 10% more than single-row due to greater LAI, NDVI, and node and pod production. Rice field experiments quantified N loss via ammonia volatilization and determined grain yield for various N sources and preflood application timing. Cumulative ammonia volatilization loss on Tunica clay was minimal (10% of applied N). Grain yields were 6% less when fertilizer was applied 10 days before flood (dbf) as compared to 1 dbf; N sources are available to minimize ammonia volatilization loss.

Nos últimos anos, houve rápido crescimento da utilização de substâncias que buscam aumentar a produtividade de soja, seja por alterações fisiológicas ou morfológicas. Entre estes compostos, lactofen (LC), citocinina (CK), ácido salicílico (AS) e boro (B) têm sido utilizados com esse propósito. No entanto, não existem informações científicas que atestam esses manejos, o que causa instabilidade na resposta observada no campo. Além disso, atualmente existe mais de 1000 variedades cultivadas de soja disponíveis no mercado, o que dificulta o entendimento do efeito desses produtos na cultura e soja. Visando entender as alterações fisiológicas e morfológicas que estes compostos proporcionam, objetivou-se avaliar os efeitos da época de aplicação de cinetina (KIN) e os efeitos das associações entre KIN, LC, AS e B nas variedades cultivadas NA-5909-RG (GM 6.7) e NS-7114-RR (GM 7.1). Foram realizados dois experimentos em condições de campo no Centro Universitário de Patos de Minas, Patos de Minas (MG), durante o período de novembro de 2014 a maio de 2015. Foram realizadas avaliações fisiológicas (atividade da nitrato redutase - ANR, teor de proteína total solúvel na folha, atividade da peroxidase e superóxido dismutase, teor de H2O2, peroxidação de lipídios e teor de prolina) e fenométricas (valor Spad, massa de matéria seca de raiz, caule, folhas e vagens), além do número de vagens, nós, ramificações e produtividade. Para o primeiro experimento, foram utilizados quatro tratamentos: (i) Controle; (ii) KIN (V4); (iii) KIN (V6) e (iv) KIN (V4+V6) com cinco repetições em delineamento inteiramente casualizado. No segundo experimento, foram utilizados dezesseis tratamentos: (i) Controle; (ii) L; (iii) KIN; (iv) AS; (v) B; (vi) LC + KIN; (vii) LC + AS; (viii) LC + B; (ix) LC + KIN + AS; (x) LC + KIN + B; (xi) LC + AS + B; (xii) LC + KIN + AS + B; (xiii) KIN + AS; (xiv) KIN + B; (xv) KIN + AS + B e (xvi) AS + B em duas variedades cultivadas, NA-5909-RG e NS-7114-RR, em esquema fatorial 16x2 com quatro repetições em delineamento em blocos ao acaso. Com base nos resultados obtidos, conclui-se que: (i) a aplicação de KIN em V4, V6 ou V4+V6 aumenta a ANR e o teor de proteína na folha, reduz o nível de estresse e aumenta o acúmulo de massa de matéria seca e a produtividade; (ii) a aplicação de LC aumenta o nível de estresse das plantas e incrementa a produtividade apenas na variedade cultivada do GM 7.1; (iii) a aplicação de KIN proporciona maior efeito na produtividade na variedade cultivada NS-7114-RR; (iv) mesmo a variedade cultivada NA-5909-RG sendo mais responsivo à aplicação de AS para as características fisiológicas e fenométricas, este incrementou a produtividade apenas no NS-7114-RR; (v) a aplicação de B proporciona os melhores efeitos na NS-7114-RR; (vi) o efeito das associações entre LC + CK + AS e AS + B é mais estável na NS-7114-RR, enquanto que na NA-5909-RG, os efeitos mais estáveis foram observados para LC + CK + AS + B; (vii) considerando as duas variedades cultivadas, a associação entre LC + CK proporciona o maior incremento de produtividade; e (viii) a variedade cultivadas NS- 7114-RR manteve maior teor de proteína na folha, superior acúmulo de massa de matéria seca durante o final do período do enchimento de grãos e maior massa de 1000 grãos, o que repercutiu em maior produtividade em relação ao NA-5909-RG. / In recent years, there has been a rapid growth of the substance use to increase soybean productivity, either physiological or morphological changes. Among these compounds, lactofen (LC), cytokinins (CK), salicylic acid (SA) and boron (B) have been used with this purpose. However, there is no scientific information that attest these managements, which cause instability in the observed response in field. In addition, there are currently more than 1,000 soybean cultivars available on the market, making it difficult to understand the product effect on the soybean crop. In order to understand the physiological and morphological changes that these compounds provide, this work aimed to evaluate the effects of kinetin (KIN) application time and the effects of the associations between KIN, LC, SA and B in the NA-5909-RG (GM 6.7) and NS-7114-RR (GM 7.1) cultivars. Two field experiments were carried out at the University of \'Patos de Minas\' (UNIPAM), \'Minas Gerais\' state, Brazil, during the period from November 2014 to May 2015. Physiological (nitrate reductase activity, total soluble protein content in leaf, peroxidase and superoxide dismutase activity, H2O2 content, lipid peroxidation and proline content) and phenometric (Spad value, dry matter of root, stem, leaves and pods) evaluations were done, as well as the number of pods, nodes, branches and productivity. For the first experiment, four treatments were used: (i) Control; (ii) KIN (V4); (iii) KIN (V6) and (iv) KIN (V4+V6) with five replications in a randomized block design. In the second experiment, sixteen treatments were used: (i) Control; (ii) LC; (iii) KIN; (iv) SA; (v) B; (vi) LC + KIN; (vii) LC+SA; (viii) LC + B; (ix) LC + KIN+SA; (x) LC + KIN + B; (xi) LC+SA+B; (xii) LC + KIN+SA+B; (xiii) KIN+SA; (xiv) KIN + B; (xv) KIN+SA+B and (xvi) SA+B. The NA-5909-RG and NS-7114-RR cultivars (factorial 16x2) were used with four replications in a randomized block design. Based on the results, it is possible to conclude that: (i) the application of KIN in V4, V6 or V4+V6 increases the nitrate reductase activity and leaf protein content, reduces the stress level, increases the total dry matter production and productivity; (ii) the LC application increases the plant stress level and productivity (only in the maturation group 7.1); (iii) the KIN application provides greater effect on productivity in the NS-7114-RR cultivar; (iv) the NA-5909-RG cultivar is more responsive to the application of SA, however it increased productivity only in the NS-7114- RR cultivar; (v) the B application provides the best effects on NS-7114-RR cultivar; (vi) the effects of LC + CK + SA and SA + B were more stable in the NS-7114-RR cultivar, while the NA-5909-RG cultivar was more stable for LC + CK + SA + B application; (vii) considering two varieties, LC + CK application provides the greatest increase in productivity; and (viii) the NS-7114-RR cultivar maintained higher protein content on the leaf, higher total dry matter accumulation during the late grain filling period and higher mass of 1,000 grains, which reflected in higher productivity compared to the NA-5909-RG cultivar.

Nos últimos anos, houve rápido crescimento da utilização de substâncias que buscam aumentar a produtividade de soja, seja por alterações fisiológicas ou morfológicas. Entre estes compostos, lactofen (LC), citocinina (CK), ácido salicílico (AS) e boro (B) têm sido utilizados com esse propósito. No entanto, não existem informações científicas que atestam esses manejos, o que causa instabilidade na resposta observada no campo. Além disso, atualmente existe mais de 1000 variedades cultivadas de soja disponíveis no mercado, o que dificulta o entendimento do efeito desses produtos na cultura e soja. Visando entender as alterações fisiológicas e morfológicas que estes compostos proporcionam, objetivou-se avaliar os efeitos da época de aplicação de cinetina (KIN) e os efeitos das associações entre KIN, LC, AS e B nas variedades cultivadas NA-5909-RG (GM 6.7) e NS-7114-RR (GM 7.1). Foram realizados dois experimentos em condições de campo no Centro Universitário de Patos de Minas, Patos de Minas (MG), durante o período de novembro de 2014 a maio de 2015. Foram realizadas avaliações fisiológicas (atividade da nitrato redutase - ANR, teor de proteína total solúvel na folha, atividade da peroxidase e superóxido dismutase, teor de H2O2, peroxidação de lipídios e teor de prolina) e fenométricas (valor Spad, massa de matéria seca de raiz, caule, folhas e vagens), além do número de vagens, nós, ramificações e produtividade. Para o primeiro experimento, foram utilizados quatro tratamentos: (i) Controle; (ii) KIN (V4); (iii) KIN (V6) e (iv) KIN (V4+V6) com cinco repetições em delineamento inteiramente casualizado. No segundo experimento, foram utilizados dezesseis tratamentos: (i) Controle; (ii) L; (iii) KIN; (iv) AS; (v) B; (vi) LC + KIN; (vii) LC + AS; (viii) LC + B; (ix) LC + KIN + AS; (x) LC + KIN + B; (xi) LC + AS + B; (xii) LC + KIN + AS + B; (xiii) KIN + AS; (xiv) KIN + B; (xv) KIN + AS + B e (xvi) AS + B em duas variedades cultivadas, NA-5909-RG e NS-7114-RR, em esquema fatorial 16x2 com quatro repetições em delineamento em blocos ao acaso. Com base nos resultados obtidos, conclui-se que: (i) a aplicação de KIN em V4, V6 ou V4+V6 aumenta a ANR e o teor de proteína na folha, reduz o nível de estresse e aumenta o acúmulo de massa de matéria seca e a produtividade; (ii) a aplicação de LC aumenta o nível de estresse das plantas e incrementa a produtividade apenas na variedade cultivada do GM 7.1; (iii) a aplicação de KIN proporciona maior efeito na produtividade na variedade cultivada NS-7114-RR; (iv) mesmo a variedade cultivada NA-5909-RG sendo mais responsivo à aplicação de AS para as características fisiológicas e fenométricas, este incrementou a produtividade apenas no NS-7114-RR; (v) a aplicação de B proporciona os melhores efeitos na NS-7114-RR; (vi) o efeito das associações entre LC + CK + AS e AS + B é mais estável na NS-7114-RR, enquanto que na NA-5909-RG, os efeitos mais estáveis foram observados para LC + CK + AS + B; (vii) considerando as duas variedades cultivadas, a associação entre LC + CK proporciona o maior incremento de produtividade; e (viii) a variedade cultivadas NS- 7114-RR manteve maior teor de proteína na folha, superior acúmulo de massa de matéria seca durante o final do período do enchimento de grãos e maior massa de 1000 grãos, o que repercutiu em maior produtividade em relação ao NA-5909-RG. / In recent years, there has been a rapid growth of the substance use to increase soybean productivity, either physiological or morphological changes. Among these compounds, lactofen (LC), cytokinins (CK), salicylic acid (SA) and boron (B) have been used with this purpose. However, there is no scientific information that attest these managements, which cause instability in the observed response in field. In addition, there are currently more than 1,000 soybean cultivars available on the market, making it difficult to understand the product effect on the soybean crop. In order to understand the physiological and morphological changes that these compounds provide, this work aimed to evaluate the effects of kinetin (KIN) application time and the effects of the associations between KIN, LC, SA and B in the NA-5909-RG (GM 6.7) and NS-7114-RR (GM 7.1) cultivars. Two field experiments were carried out at the University of \'Patos de Minas\' (UNIPAM), \'Minas Gerais\' state, Brazil, during the period from November 2014 to May 2015. Physiological (nitrate reductase activity, total soluble protein content in leaf, peroxidase and superoxide dismutase activity, H2O2 content, lipid peroxidation and proline content) and phenometric (Spad value, dry matter of root, stem, leaves and pods) evaluations were done, as well as the number of pods, nodes, branches and productivity. For the first experiment, four treatments were used: (i) Control; (ii) KIN (V4); (iii) KIN (V6) and (iv) KIN (V4+V6) with five replications in a randomized block design. In the second experiment, sixteen treatments were used: (i) Control; (ii) LC; (iii) KIN; (iv) SA; (v) B; (vi) LC + KIN; (vii) LC+SA; (viii) LC + B; (ix) LC + KIN+SA; (x) LC + KIN + B; (xi) LC+SA+B; (xii) LC + KIN+SA+B; (xiii) KIN+SA; (xiv) KIN + B; (xv) KIN+SA+B and (xvi) SA+B. The NA-5909-RG and NS-7114-RR cultivars (factorial 16x2) were used with four replications in a randomized block design. Based on the results, it is possible to conclude that: (i) the application of KIN in V4, V6 or V4+V6 increases the nitrate reductase activity and leaf protein content, reduces the stress level, increases the total dry matter production and productivity; (ii) the LC application increases the plant stress level and productivity (only in the maturation group 7.1); (iii) the KIN application provides greater effect on productivity in the NS-7114-RR cultivar; (iv) the NA-5909-RG cultivar is more responsive to the application of SA, however it increased productivity only in the NS-7114- RR cultivar; (v) the B application provides the best effects on NS-7114-RR cultivar; (vi) the effects of LC + CK + SA and SA + B were more stable in the NS-7114-RR cultivar, while the NA-5909-RG cultivar was more stable for LC + CK + SA + B application; (vii) considering two varieties, LC + CK application provides the greatest increase in productivity; and (viii) the NS-7114-RR cultivar maintained higher protein content on the leaf, higher total dry matter accumulation during the late grain filling period and higher mass of 1,000 grains, which reflected in higher productivity compared to the NA-5909-RG cultivar.

The occasional failure of glyphosate to control all weeds throughout the entire growing season has prompted growers to sometimes use herbicides other than glyphosate on glyphosate-tolerant soybean. Field studies were conducted in 1999 and 2000 to investigate potential crop injury from several herbicides on glyphosate-tolerant soybean, and to determine the relationship between soybean maturity, planting date, and herbicide treatment on soybean injury, leaf area index (LAI), and yield. Three glyphosate-tolerant soybean cultivars representing maturity groups III, IV and V were planted at dates representing the full-season and double-crop soybean production systems used in Virginia. Within each cultivar and planting date, 15 herbicide treatments, in addition to a control receiving only metolachlor preemergence, were applied to cause multiple levels of crop injury. Results of this study indicate that glyphosate-tolerant soybean generally recovered from early-season herbicide injury and LAI reductions; however, reduced yield occurred with some treatments. Yield reductions were more common in double-crop soybean than in full-season soybean. In full-season soybean, most yield reductions occurred only in the early maturing RT-386 cultivar. These yield reductions may be attributed to the reduced developmental periods associated with early maturing cultivars and double-crop soybean that often lead to reduced vegetative growth and limited LAI. Additional reductions of LAI by some herbicide treatments on these soybean may have coincided with yield reductions; however, reduced LAI did not occur with all yield reducing treatments. Therefore, soybean LAI response to herbicide treatments does not always accurately indicate the potential detrimental effects of herbicides on soybean yield. Further, yield reductions associated with herbicide applications occurred, although soybean sometimes produced leaf area exceeding the critical LAI level of 3.5 to 4.0 which is the minimum LAI needed for soybean to achieve maximum yield. / Master of Science

Kenntnisse zur Blattflächenentwicklung von Silomaissorten während der Vegetationsperiode sind erforderlich, um die Ausreife der Pflanzen charakterisieren und neue Sorte bewerten zu können. Die Blattfläche ist eine Funktion von Blattzahl und Blattfläche und kann den Ertrag und die Futterqualität von Silomais in Abhängigkeit von den Umweltbedingungen in unterschiedlichem Ausmaß variieren. Ein maßgebliches Kriterium für das Erreichen einer guten Futterqualität ist die Prognose des optimalen Erntetermins. In den Jahren 2002 und 2003 wurden zwei Experimente am Standort Berge des Institutes für Pflanzenbauwissenschaften (Landwirtschaftlich-Gärtnerische Fakultät der Humboldt-Universität zu Berlin) durchgeführt, um zu zeigen, wie sich Silomaissorten der Reifegruppen früh und mittelfrüh im Blattflächenindex, in der Blattentwicklung sowie spezifischen Blattfläche unterscheiden und welche Unterschiede zwischen zwei Messmethoden zur Bestimmung des Blattflächenindexes bestehen. Unter Beachtung von Ertrag und Futterqualität haben sich bei limitiertem Wasserangebot unter den gegebenen Standortbedingungen Sorten mit einer geringeren Anzahl von Blattgenerationen (13 bis 16) als geeignet erwiesen. Um Trockenmassegehalte in der Gesamtpflanze im optimalen Bereich von 30 bis 35 % im Erntegut garantieren zu können, sollte Silomais speziell unter trocken-heißen Abreifebedingungen dann geerntet werden, wenn mindestens zwei Blätter unterhalb des Kolbenansatzes noch grün sind. / Knowledge of leaf area development of silage maize varieties during the vegetation period is useful in the characterisation of the maturity conditions of plants and in the evaluation of new varieties. Leaf area, which is a function of leaf number and leaf size may affect yield and quality parameters of silage maize at varying levels, depending on the environmental conditions under which the crops are grown. One of the criteria for obtaining good quality forage is prognosis for optimum harvest time. Two experiments were conducted in 2002 and 2003 at Berge research station, belonging to the Institute of Crop Science (Faculty of Agriculture and Horticulture, Humboldt-University Berlin) with the aim to assess how silage maize varieties of maturity group early and mid early differ in LAI, leaf area development, specific leaf area, what differences exist between the two methods used to measure LAI. Considering yield and forage quality, under the condition of location Berge, with limited water availability, varieties with fewer leaves (13-16) may be suitable. To maintain the whole plant dry matter content within the optimum range (30-35%), especially under drought condition, harvest time must fall within the period when at least a minimum of two leaves below the cob leaf are still green.

Winter cover crops grown in rotation with grain crops can be an efficient integrated pest management tool (IPM). However, cover crop biomass production and thus successful provisioning of ecosystem services depend on a timely planting and cover crop establishment after harvest of a cash crop in the fall. One potential management adaptation is the use of short-season soybeans to advance cover crop planting date in the fall. Cover crops planted earlier in the fall may provide a greater percentage of ground cover early in the season because of higher biomass accumulation that may improve weed suppression. However, adapting to short-season soybeans could have a yield penalty compared to full-season soybeans. In addition, it is unclear if further increasing cover crop growing season and biomass production under environmental conditions in Kentucky could limit nitrogen and water availability for the next cash crop. This thesis combines the use of field trials and a crop simulation model to address the research questions posed. In Chapter 1, field trials evaluating yield and harvest date of soybean maturity group (MG) cultivars from 0 to 4 in 13 site-years across KY, NE, and OH, were used to calibrate and evaluate the DSSAT crop modeling software (v 4.7). The subsequent modeling analysis showed that planting shorter soybean maturity groups (MG) would advance date of harvest maturity (R8) by 6.6 to 11 days per unit decrease in MG for May planting or by 1 to 7.3 days for July planting. The earliest MG cultivar that maximized yield ranged from MG 0 to 3 depending on the location, allowing a winter-killed cover crop to accumulate between 257 to 270 growing degree days (GDD) before the first freeze occurrence when soybean was planted in May, and between 280 to 296 GDD when soybean was planted in July. Winter-hardy cover crops could accumulate 701 to 802 GDD following soybean planted in May and 329 to 416 GDD after soybean planted in July. In Chapter 2, a two-year field trial was conducted at Lexington, KY to evaluate the effect of a soybean – cover crop rotation with soybean cultivars MG 1, 2, 3 or 4 on cover crop biomass and canopy cover, and on weed biomass in the fall and the following spring. Results showed that having cover crops was an efficient management strategy to reduce weed biomass in the fall and spring compared to no cover treatment. Planting cover crops earlier in the fall after a short-season soybean increased cover crop biomass production and percentage of ground cover in the fall, but not the following spring. Planting cover crop earlier after a short-season soybean did not improve weed suppression in the fall or spring compared to a fallow control with full-season soybean. Having a fall herbicide application improved weed control when there was a high pressure of winter annual weeds. By the spring, delaying cover crop termination increased cover crop biomass but also did weed biomass. In Chapter 3, a soybean – cover crop – corn rotation was simulated to evaluate the effect of different soybean MG and cover crop termination, as well as year to year variability on water and nitrogen availability for the next corn crop in Lexington, KY. Simulations showed that when cover crops were terminated early, they did not reduced soil available water at corn planting. However, introducing a non-legume cover crop reduced total inorganic nitrogen content in the soil profile by 21 to 34 kg ha-1 implying 15 to 30 kg ha-1 less in corn nitrogen uptake. Cover crop management that was able to maintain similar available water values than fallow treatment while minimizing nitrogen uptake differences was cover crops planted after soybean MG 4 with an early termination. However, the best management strategies that will maximize ecosystem services from cover crops as well as cash crop productivity may need to be tailored to each environment, soil type, irrigation management, and must consider year-to-year variability.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objectives of this thesis were: To estimate the relative maturity group of old and modern soybean cultivars used in Southern Brazil; To quantify the branches contribution in the leaf area index; To characterize the development and the overlap period of vegetative and reproductive phases, growth in height and the emission of nodes after the beginning of flowering in determinate and indeterminate plant type cultivars in different sowing dates and soybean regions in Rio Grande do Sul and; To identify key biophysical and management factors governing variation in soybean yield potential in Southern Brazil. Were conducted 47 experiments using 23 soybean cultivars in five growing seasons (2010/2011, 2011/2012, 2012/2013, 2013/2014 and 2014/2015) at 12 sites in Rio Grande do Sul. The relative maturity group these cultivars that had not yet been classified ranged from 4.8 to 7.3. Most cultivars showed a reduction on total leaf area index, maximum, of main stem and of branches, in the duration of the reproductive phase, of the total development cycle with delay on sowing date regardless of the maturity group and type of growth. The indeterminate type cultivars had a higher overlap period of vegetative and reproductive phases, growing in height and emission nodes after the beginning of flowering bigger than determinate type cultivars. The potential yield ranged from 2.8 up to 6.0 Mg ha-1, depending on the amount and distribution of water during the growing season and the photothermal coefficient during reproductive stages of the soybean. / Os objetivos desta tese foram: Estimar o grupo de maturidade relativa de cultivares antigas e modernas de soja; Quantificar a contribuição das ramificações no índice de área foliar; Caracterizar o desenvolvimento e a duração do período de sobreposição das fases vegetativa e reprodutiva, o crescimento em estatura e a emissão de nós após o início do florescimento em cultivares modernas de soja com diferentes grupos de maturidade relativa, tipos de crescimento, semeadas em épocas e regiões produtoras de soja no Rio Grande do Sul e; Identificar as variáveis meteorológicas e de manejo que governam o potencial de rendimento em soja no sul do Brasil. Foram conduzidos 47 experimentos utilizando 23 cultivares de soja, durante cinco estações de crescimento (2010/2011, 2011/2012, 2012/2013, 2013/2014 e 2014/2015) em 12 locais no Rio Grande do Sul. O grupo de maturidade relativa das cultivares que ainda não tinham sido classificadas variou de 4.8 a 7.3. Há redução dos valores de índice de área foliar máximo, da haste principal e das ramificações, da duração da fase reprodutiva e do ciclo total de desenvolvimento, com o atraso da época de semeadura, independentemente do grupo de maturidade relativa e tipo de crescimento. As cultivares com tipo de crescimento indeterminado apresentam maior período de sobreposição das fases vegetativa e reprodutiva, crescimento em estatura e emissão de nós após o início do florescimento do que as cultivares determinadas. O potencial rendimento de soja variou de 2,8 até 6,0 Mg ha-1, dependendo da quantidade e distribuição da água durante a estação de crescimento e do coeficiente fototérmico durante os estágios reprodutivos da soja.