Microsoft Word - 2-Agra_26241.doc 11 Original Article Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 TEMPERATURE AND HUMIDITY OF SOIL COVERED WITH PERENNIAL HERBACEOUS LEGUMES IN THE SEMIARID REGION OF MINAS GERAIS STATE, BRAZIL TEMPERATURA E UMIDADE DO SOLO COBERTO COM LEGUMINOSAS HERBÁCEAS PERENES NA REGIÃO SEMI-ÁRIDA DO ESTADO DE MINAS GERAIS, BRASIL Diego Mathias Natal da SILVA1; Fábio Luiz de OLIVEIRA2; Ricardo Borges TEODORO3; Claudenir FÁVERO4; Mateus Augusto Lima QUARESMA5 1. Post doctorate in Plant Production of Centro de Ciências Agrárias da Universidade Federal do Espírito Santo - CCA / UFES, Alegre, ES, Brazil. diegoufvjm@yahoo.com.br; 2. PhD in Plant Science, Teacher of the CCA / UFES, Alegre, ES, Brazil; 3. Master in Plant Production of Universidade Federal dos Vales do Jequitinhonha e Mucuri - UFVJM, Diamantina, MG, Brazil; 4. PhD in Soil Science and Plant Nutrition, Professor of UFVJM, Diamantina, MG, Brazil; 5. Doctoral student in Plant Production of the CCA / UFES, Alegre, ES, Brazil ABSTRACT: Agricultural sustainability of areas in semiarid region, is directly related to soil management, emphasizing especially the continuous coverage strategy. In this sense, this study aimed to evaluate the influence of perennial legumes on soil coverage, temperature and moisture in the semiarid region of Minas Gerais, Brazil. The study used a randomized blocks experimental, with 9 m2, design and treatments consisted of bare soil cultivated with the following legumes: tropical kudzu (Pueraria phaseoloides), calopo (Calopogonium mucunoides), perennial peanut (Arachis pintoi), perennial soybean (Glycine wightii) and stylosanthes Campo Grande (mixture of Stylosanthes capitata and Stylosanthes macrocephala), with four replications. Soil coverage, temperature and moisture rates were evaluated. Due to the soil protection provided by the biomass production, the use and management of cover plants in semiarid region of Minas Gerais contributed to the temperature reduction and to the conservation of soil moisture, both essential for the agricultural production in this region. Calopo, tropical kudzu and perennial peanut provided greater soil coverage and, consequently, they provided greater reduction in temperature and higher moisture retention in soil. In more advanced stages of the cycle, the perennial soybean also provided good soil coverage, temperature reduction and moisture retention in the soil. KEYWORDS: Cover plant. Green manure. Caatinga. Sustainability. INTRODUCTION In tropical regions, agricultural soils exposed to climatic, thermal and water phenomena need continuous protection in order to maintain their productive conditions. The management and direct exposure result in an increase in temperature and evaporation, loss of soil and nutrients, reduction of soil organic matter and destruction of the original structure of the soil, with consequence on agricultural productivity (PERIN et al., 1998). Soil degradation in the Brazilian semiarid region is directly related to its inadequate use and management, through the excess in the use of mechanization, especially the plowing and harrowing, bad programmed fertilization, being aggravated by prolonged drought. Despite the rains being sporadic, rainfall events occur at certain times and places with great intensity, coupled with the low efficiency of the agricultural systems to protect soils, resulting in degrading events of great magnitude (ALBUQUERQUE et al., 2002). However, the sustainability of these Caatinga areas, a Brazilian biome located in the semiarid region, can be achieved through the proper management of the soil, with emphasis to the use of cover plants (FARIA et al., 2004). The adoption of the green manure practice performed with species of the family Fabaceae may represent an important strategy in the pursuit of the sustainability of the agroecosystems in this biome, given the benefits to the soil such as: permanent protection against the major causative agents of soil degradation (LEITE et al., 2010), maintenance of moisture, decrease in maximum temperatures and thermal amplitude of the soil (TORRES et al., 2006), in addition to the supply of N by biological fixation (GAMA-RODRIGUES et al., 2007), among other benefits, especially with the use of perennial herbaceous species, which have great potential as soil coverage, for covering the ground for some months or throughout the year (PERIN et al., 2009). In tropical climates, the water transpired by plants is often lower than that evaporated directly Received: 12/04/15 Accepted: 20/10/15 12 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 from the soil (PRIMAVESI, 2002). Thus, the use of cover plants in farming enables greater optimization of productive resources, especially water, a primary limiting resource for the agricultural activity of the Brazilian semiarid region (OLIVEIRA et al., 2002). Moreover, a bare soil will have its surface encrusted by rain, and as a consequence, the surface water runoff and, hence, the erosion will be more intense than the ones occurring in a soil covered by vegetation (PRIMAVESI, 2002). The identification of legumes species adapted to the edaphoclimatic conditions of the region where they will be inserted is essential to ensure the successful use of these plants as permanent coverage. These because the success of the practice depends on the knowledge related to the behavior, adaptation, requirement (nutritional, photoperiodic life, water) and residence time of the species in the environment in which it was introduced. In recent years, several studies regarding the behavior of herbaceous perennial legumes were performed (ESPINDOLA et al., 2005; GUERRA et al., 2007; PERIN et al., 2009). However, information on the behavior of these species in the Caatinga conditions are scarce, especially for the region of Jequitinhonha Valley (Vale do Jequitinhonha) in Minas Gerais, Brazil. Thus, this study aimed to evaluate the influence of perennial herbaceous legumes on soil coverage, temperature and moisture in the semiarid region of Minas Gerais, Brazil. MATERIAL AND METHODS The study was conducted in the experimental area of the Escola Família Agrícola de Jacaré – EFAJ in city of Itinga, MG, Brazil, at latitude 16° 28' 04" South, longitude 41° 59' 50" West and altitude of 672 m, in the region of occurrence of Caatinga biome in the Middle Jequitinhonha. The region is characterized by its tendency to semiaridness, with an average annual temperature of 24.4°C and annual rainfall of 700 mm, with high concentrations in the summer months (OLIVEIRA et al., 2002), corroborating the meteorological data observed in this study (Figure 1). Figure 1. Average monthly rainfall (mm), maximum and minimum temperature (° C) observed in the period from December 2008 to February 2010, in Araçuaí-MG. Source: Data from INMET Network, 2014. The area in which the experiment took place was in fallow, covered by spontaneous vegetation, predominantly Cenchrus echinatus, the Poaceae family, followed by Bidens subalternans, Asteraceae family, and the soil was classified as Yellow Argisol (EMBRAPA, 2014). Soil samples (0 to 20 cm) were collected and their chemical and granulometric characteristics showed the following values: pH 5.9 in water; 0.0029 dag kg-1 of P (Mehlich 1); 0.0426 dag kg -1 of K; 28.0 molc dm-3 of Ca; 18.0 molc dm-3 of Mg; 2.0 molc dm-3 of Al; 63% base saturation; 1.7 dag kg-1 of organic matter; 64% sand, 10% silt and 26% clay. The study used a randomized blocks experimental design and treatments consisted of bare soil cultivated with the following legumes: tropical kudzu (Pueraria phaseoloides), calopo (Calopogonium mucunoides), perennial peanut (Arachis pintoi), perennial soybean (Glycine wightii) and stylosanthes Campo Grande (mixture of 13 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 Stylosanthes capitata and Stylosanthes macrocephala), with four replications. The area of each plot was 9 m2 (3 m x 3 m), and central 2 m2 was considered useful area. Before sowing, only a hand weeding was carried out in the entire experimental area, followed by the opening of planting rows of legumes. Legumes were sown in December 2008 at a depth of 2 cm, furrow spacing of 40 cm, with an average density of 20 seeds per meter of furrow. The seeds did not undergo any kind of treatment to break dormancy. The rate of soil cover was determined at 30; 60; 90; 120; 150; 180; 265; 325; 355; 375; 405 and 440 days after sowing (DAS) the legumes, by the method of number of intersections described by Fávero et al. (2001), using a wooden frame 1 m² strings containing a network, spaced 10 cm, 100 defining points on the area in which they wanted to determine the coverage. The intersection of two perpendicular strings defines a point and is an area, as adopted spacing. It is reported then the number of intersections that are on vegetation. The sum of these points, which means the sum of the areas that represent these points, in relation to the total area of the set points, estimates the soil cover. Soil temperature was measured at the depths of 5; 10 and 15 cm, at 30; 60; 90; 120; 150; 355; 375 and 440 DAS, always at 2 p.m. Instant readings were performed by a digital thermometer, model SoloTerm 1200, which uses metallic probe. Volumetric soil moisture was indirectly determined through the soil bulk density, by standard greenhouse method (BERNARDO et al., 2006.), at 30; 60; 90; 120; 150; 180; 265, 355 and 375 DAS. The collections were performed in the layer of 0 to 5 cm under the soil. For verification of normality and homoscedasticity of data were used Liliefors and Cochran & Bartlett tests, respectively. Data were subjected to analysis of variance by F test and the means were compared by Tukey test at 5% probability. It calculated the Pearson correlation coefficients to determine the degree of relationship between the variables. Statistical analyses were performed using the SISVAR statistical software (FERREIRA, 2008). RESULTS AND DISCUSSION There was no difference among the legumes regarding the time of seedling emergence. Most species showed values which were greater than or equal to 80% emergence 7 days after sowing (DAS). Calopo and perennial peanut had higher percentages of soil coverage, around 99% and 74%, respectively, at 90 DAS (Figure 2). Tropical kudzu showed slower initial growth when compared with calopo and perennial peanut, however, as it can be seen in Figure 2, from 120 days on, the three species completely covered the soil. Figure 2. Soil coverage by herbaceous perennial legumes in the Caatinga region, in the Middle Jequitinhonha Valley. *Vertical lines indicate the least significant difference at 5% using the Tukey method to compare treatment means. Similar behavior was also identified by PERIN et al. (2000) and GUERRA et al. (2007) in the Atlantic Forest region, for calopo, tropical kudzu and perennial peanut, when the authors observed that the average time for the total soil coverage was 106; 106 and 114 days, respectively. In the current study, these three species were those that had the highest rates of soil coverage up to 325 DAS, highlighting the calopo. Up to 265 DAS, the driest period of the performed evaluations (Figure 1), the perennial soybean showed 88% maximum soil 14 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 coverage, at 120 DAS, while the stylosanthes showed 63% maximum soil coverage (Figure 2). All species started a reduction process in the rate of soil coverage at 120 DAS, which was more evident for Stylosanthes species, perennial soybean and perennial peanut. This occurred due to the high temperatures and shortages of rainfall, since it was the beginning of the dry season, which is characteristic of this region (Figure 1). As the dry season spread, the plants responded with significant senescence of leaves, which reduced soil protection. However, as the deposited leaves were not removed from the area and the low coverage rate that legumes offer, was due to the deposited organic material. Another factor that probably contributed to the decline in the coverage rate was the beginning of the reproductive period of legumes. The stylosanthes presented, in all plots, flowering plants at 120 DAS. The perennial soybean and calopo had full bloom at 150 DAS. The later flowering was tropical kudzu which showed around 20% of flowering plants from 150 DAS, lasting up to 180 DAS. This behavior of the species, except for the tropical kudzu, strengthens the potential for their use as permanent living mulch in the studied environment, because the production of seeds prior to the dry period ensures the reseeding of areas and the maintenance of the species through their restoration when the rainy season returns. At 265 DAS, in a period of complete drought in the region, August 2009 (Figure 1), calopo and tropical kudzu had higher rates of soil coverage (Figure 2) provided by the senescent phytomass of these legumes. However, the tropical kudzu was the only one that showed green cover in this period, around 10% of the phytomass covering the soil. The higher soil coverage provided by calopo and tropical kudzu can be explained by the increased production of both green and senescent phytomass by these species. With the onset of the rainy season in October 2009 (Figure 1), at 325 DAS, legumes resumed growth. In this period, calopo showed lower soil coverage in relation to 265 DAS, a fact explained by the decomposition of senescent phytomass previously deposited to the soil and by the slow initial rate of coverage promoted by the growth of young plants, since calopo had little regrowth. On the other hand, regarding tropical kudzu, the increase in the rate of soil coverage was small, because this species already had soil coverage around 80% at 265 DAS (Figure 2), promoted by senescent phytomass. In this period, the increase in the rate of soil coverage was greater for perennial soybean and perennial peanut. This was probably due to the lower accumulation of senescent phytomass on the soil during the dry season, providing less soil coverage at 265 DAS. However, with the onset of rains (Figure 1), these species began to grow again and recovered the soil reaching rates near 100% coverage at 355, 375 and 405 DAS, equaling the tropical kudzu. With the onset of rains, differences were observed between the legumes regarding their way of recovery. All legumes sprouted, except calopo, which has been reestablished via germination of the seeds released after the fruiting occurred in the dry season. Among the sprouted species, tropical kudzu had excelled mainly by the rate of restoration of its vegetative mass, while calopo stood out for the high seed production, demonstrating its potential in reseeding the areas. After the resumption of growth, with the onset of rains, calopo completely covered the soil only at 405 DAS (Figure 2). This is probably due to the physical barrier promoted by senescent phytomass itself, which remained in the area after the dry season, thus hindering the emergence of seedlings. All legumes have fickle habit of growth, with the exception of perennial peanut which shows creeping habit (stoloniferous) and Stylosanthes Campo Grande, a mixture of Stylosanthes capitata which features a more vertical growth habit, and Stylosanthes macrocephala, which presents a more horizontal growth habit, which may have influenced the lower soil coverage observed in this last legume. In general, the soil coverage provided by legumes at 440 DAS decreased (Figure 2). This fact is probably related to the low rainfall and high temperatures occurring during this period (Figure 1), which could have caused stress in the legumes, and as a result, decrease in soil coverage, except for the tropical kudzu, which maintained 100% coverage, showing its greater tolerance to high temperatures and low soil moisture. It is noteworthy that, at 440 DAS, legumes restated their reproductive period, since flower buds were observed in all species. This behavior strengthens the potential for the use of some legumes as permanent cover in semi-arid environment, because seed production can ensure the reseeding of areas, representing an alternative for the species preservation. In general, with the return of the rainy season and the subsequent resumption of growth of legumes at 325 DAS, it can be stated that tropical 15 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 kudzu, calopo, perennial peanut and perennial soybean had a satisfactory soil coverage rate for the semiarid region where the study was performed, especially the tropical kudzu. As for the variation of soil temperature, we can observe differences between the soil covered with some legumes and bare soil, at all periods and depths evaluated (Table 1). It was observed that from 30 to 90 DAS, the highest soil coverage observed for calopo, tropical kudzu and perennial peanut (Figure 2) also promoted greater reduction of soil temperature compared with the bare soil at all depths evaluated (table 1). However, from 120 DAS, the coverage of all legumes, with less intensity in stylosanthes, caused reduction of soil temperature, compared with bare soil. Table 1. Temperature (°C) of soil with different plant covers, at 2 p.m., measured at the depths of 5, 10 and 15 cm, in eight periods. Cover plants Temperature (°C) ------------------------------------Days after sowing------------------------------------- 30 60 90 120 150 355 375 440 5 cm Tropical kudzu 35.3 bc 38.0 b 42.6 b 25.4 cd 31.7 b 28.6 bc 24.9 d 26.7 c Calopo 32.3 d 29.9 d 36.9 d 23.9 e 31.1 b 32.2 b 27.2 c 29.7 b Perennial peanut 34.1 cd 32.5 c 39.5 c 24.5 de 30.2 b 27.3 c 26.0 cd 26.7 c P. soybean 36.6 abc 39.0 ab 43.6 ab 26.3 c 31.8 b 26.5 c 26.6 c 26.5 c Stylosanthes 36.6 ab 39.7 ab 43.9 ab 28.3 b 33.7 b 31.9 b 30.7 b 31.3 b Bare soil 38.0 a 40.8 a 45.2 a 34.2 a 42.4 a 45.8 a 44.3 a 45.1 a CV% 5.8 4.3 4.7 4.2 5.7 5.3 2.2 3.6 10 cm Tropical kudzu 31.9 bcd 37.2 a 40.2 bc 24.7 c 30.1 bc 27.5 bcd 24.3 d 25.9 cd Calopo 29.8 d 29.1 c 34.1 d 23.4 d 28.7 c 30.8 b 26.6 c 28.7 bc Perennial peanut 31.1 cd 31.5 b 38.1 c 23.5 d 29.2 c 25.8 d 25.1 cd 25.4 d P. soybean 33.7 ab 37.5 a 41.8 ab 25.7 c 30.8 bc 27.1 cd 25.9cd 26.5 cd Stylosanthes 33.6 ab 38.3 a 41.1 ab 27.2 b 32.5 b 29.9 bc 29.2 b 29.5 b Bare soil 35.4 a 39.4 a 42.9 a 30.9 a 39.6 a 40.5 a 38.1 a 39.2 a CV% 4.8 4,0 3,7 3.7 5.6 5.0 2.8 4.3 15 cm Tropical kudzu 29.5 bc 35.6 a 38.0 ab 24.1 c 28.4 bc 26.6 bc 23.7 c 25.1 bc Calopo 28.2 c 28.5 b 34.8 c 23.0 d 27.1 c 28.9 b 25.7 bc 27.3 bc Perennial peanut 29.1 bc 30.4 b 36.2 bc 23.3 d 27.8 c 24.6 c 24.4 c 24.5 c P. soybean 31.1 ab 35.8 a 39.6 a 25.1 c 29.2 bc 25.9 bc 25.7 bc 25.8 bc Stylosanthes 30.8 ab 36.2 a 38.8 a 26.4 b 30.9 b 28.9 b 27.5 b 28.1 b Bare soil 32.2 a 37.2 a 40.1 a 27.6 a 37.1 a 38.1 a 35.3 a 36.7 a CV% 4.2 3.6 3.5 2.3 5.5 4.5 4.7 4.6 Values followed by the same letters, in the columns, do not differ from each other according to Tukey test (p <0.05) Temperatures observed at a depth of 5 cm were greater than the ones observed at 10 and 15 cm, which is related to a higher incidence of sunlight on the soil surface. The highest values of soil temperature were observed at 90, 355, 375 and 440 DAS, which is directly related to the observation of higher values for maximum temperature (Figure 1). Up to 120 DAS, the calopo coverage provided lower soil temperatures at the evaluated depths, which shows that the species has a greater ability to reduce soil temperature in less time (DAS) compared with the other evaluated legumes. However, in older age, from 355 to 440 DAS, the lowest temperatures were observed in soils covered by perennial soybean, tropical kudzu and perennial peanut (Table 1). These results demonstrate that the cover plants directly contribute to the decrease of soil temperature. However, they exhibit different behaviors, which are directly related to the rate of soil coverage, in which calopo, tropical kudzu and perennial peanut stood out, as well as perennial soybean from 355 DAS. The legumes’ growing living mass added to the senescent biomass covering the soil surface constitute a physical barrier to sunlight and to energy transfer, which hinders the heat exchange between the soil and the atmosphere (STRECK et al., 1994). This reinforces the importance of using 16 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 these species as permanent soil coverage, since soil temperatures above 40°C are considered unsuitable for plant growth (SIDIRAS; PAVAN, 1986). According to Bragagnolo; Mielniczuck (1990), lower soil temperatures were observed when higher amounts of straw were applied on its surface, indicating the importance of the presence of permanent coverage on the soil in order to maintain lower temperatures. As for the Caatinga, where high temperatures cause stress in plants and increase crop evapotranspiration, often limiting some agricultural activities, the strategy of using species in permanent coverage can represent an interesting alternative for the farmer, aiming at reducing the soil temperature. A significant difference was observed in the volume of water accumulated in the soil in relation to the coverage with different legumes (Table 2), highlighting the calopo, in which higher values from 30 to 405 DAS were observed. From 120 DAS, larger volumes of water were observed in the soil in all areas covered by the other legumes in relation to bare soil, with the exception of soil covered by stylosanthes, which showed the lowest coverage rates (Figure 2), and, therefore, only at 120 and 355 DAS it showed larger volumes of water compared with bare soil. Table 2. Water volume (mm3 cm-3) in the 0 to 5 cm layer of soil with different cover plants in ten periods. Cover plants Water volume (mm3 cm-3) -------------------------------------Days after sowing----------------------------------- 30 60 90 120 150 180 265 355 375 405 Tropical kudzu 79 c 87 ab 30 b 92 bc 66 b 43 b 27 b 64 a 78 c 59 ab Calopo 121 a 99 a 68 a 136 a 82 a 69 a 34 a 58 a 103 a 64 a Perennial peanut 101 b 90 ab 64 a 106 b 66 b 51 b 23 b 64 a 89 b 51 b Perennial soybean 87 c 97 a 34 b 105 b 65 b 43 b 25 b 63 a 85 bc 59 ab Stylosanthes 78 c 74 b 31 b 74 c 52 bc 38 bc 16 c 40 b 52 d 32 c Bare soil 76 c 75 b 27 b 63 d 40 c 31 c 11 c 32 c 46 d 32 c CV% 7.0 11.2 13.6 11.0 10.0 15.3 10.7 6.0 6.0 9.6 Values followed by the same letters, in the columns, do not differ from each other according to Tukey test (p <0.05) These results demonstrate the greater ability of some cover plants to preserve soil moisture in the Caatinga area of Minas Gerais. The best performance of calopo compared with other legumes may be related to its greater coverage capacity (Figure 2) and reduced soil temperature (Table 1) as well as the increased deposition of senescent leaves recorded throughout the experiment. These effects increase soil protection against direct sunlight, and, thus, alleviate the temperatures, decrease thermal amplitude, and entail lower evapotranspiration and higher soil moisture conservation. It is known that heatstroke in bare soil increases when compared with the protected soil, which causes more warming and, consequently, greater water evaporation (PRIMAVESI, 2002). According to Streck et al. (1994), any kind of coverage on the soil surface constitutes a physical barrier to the transfer of energy and water vapor between the atmosphere and soil, thereby, increasing the capacity of maintaining soil moisture. From 120 DAS, decreasing values were observed in the volume of water stored in the soil, regardless of legume species. This is probably due to the high temperatures and low rainfall, since it was the beginning of the dry period in the region with the lowest rainfall recorded between July and September (Figure 1), confirming the observed smaller volumes of water in the soil at 265 DAS (Table 2). However, from 355 DAS, during the rainy season (Figure 1), larger volumes of water were observed in the soil, in relation to the 265 DAS. All species, except stylosanthes, contributed to the maintenance of soil moisture. The higher humidity values were observed at 30, 120 and 375 DAS in the ground covered with calopo and minors were recorded at 265 DAS in soil covered with stylosanthes and bare soil (Table 2), demonstrating different potentials between the species on maintaining soil moisture. The low soil moisture identified in the different legumes soil covers can be explained, in part, because the studied soil had franco-sandy texture, which has low water retention capacity. However, in the case of a biome where drought is one of the major limiters for the development of agricultural activities, the use of these cover plants can alleviate water losses during critical periods, especially legumes with greater potential for natural leaf fall, as it is the case of calopo, kudzu tropical and perennial soybean. Wastes of vegetable toppings promote retention of water in its structure, releasing it gradually to the soil and making it more 17 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 humid in the surface layer, as it is in direct contact with them (OLIVEIRA; SOUZA, 2003). By calculating the Pearson coefficients, one can confirm the influence of coverage on the temperature and soil moisture, as was observed positive and significant correlation coefficient for the variables cover and soil moisture, demonstrating an increasing linear relationship between land cover and soil moisture. It was also observed correlation between coverage and soil temperature, meaningful, however, negative, showing an inversely proportional linear relationship in which with increasing the ground floor there is a drop in temperature of the soil (Table 3). Table 3. Pearson correlation coefficients (r) between the characters, cover, soil moisture and temperature. Cover Moisture Temperature Cover 1 0,69* -0,80** Moisture 1 -0.37ns Temperature 1 *Significant (p <0.05); ** Significant (p <0.01); NS not significant (p> 0.05). Considering the results, it was possible to note the importance of the management of cover plants in the studied region, since the high temperatures and the incidence of winds increase the evapotranspiration in the cultivated areas (PRIMAVESI, 2002), and such effects can be minimized by the shading and physical barrier provided by these legumes. CONCLUSIONS The use and management of cover plants in the semiarid area of Minas Gerais contribute to the relief of temperature and to the preservation of soil moisture. Calopo, tropical kudzu and perennial peanut provide greater soil coverage and, hence, greater reduction in the temperature and greater retention of soil moisture, demonstrating the potential for permanent use as cover crops in soil semiarid region. ACKNOWLEDGMENT CAPES, for the Masters scholarship granted to the first author. CNPq and MDA / SAF, for the financial support provided to the research. Escola Família Agrícola de Jacaré and the Federal University of Jequitinhonha and Mucuri Valleys, for the support and infrastructure necessary to conduct the experiment. RESUMO: A sustentabilidade agrícola das áreas na região semiárida está diretamente relacionada ao manejo do solo, ressaltando-se principalmente a estratégia de cobertura contínua. Neste sentido, esse trabalho foi realizado com o objetivo de avaliar a influência de leguminosas perenes sobre a cobertura, temperatura e umidade do solo no semiárido mineiro, Brasil. O delineamento experimental foi o de blocos ao acaso, e os tratamentos constituídos pelo solo descoberto e cultivado com as leguminosas: cudzu tropical (Pueraria phaseoloides), calopogônio (Calopogonium mucunoides), amendoim forrageiro (Arachis pintoi), soja perene (Glycine wightii) e estilosantes campo grande (mistura de Stylosanthes capitata e Stylosanthes macrocephala), com quatro repetições. Foram avaliados taxa de cobertura, temperatura e umidade do solo. Pela proteção ao solo proporcionada pela produção de biomassa, o uso e manejo de plantas de cobertura no semiárido mineiro contribuíram para a amenização da temperatura e a conservação da umidade do solo, essenciais para a produção agrícola nesta região. Calopogônio, cudzu tropical e amendoim forrageiro proporcionaram maior cobertura do solo e consequentemente promoveram maior redução da temperatura e maior retenção de umidade no solo. Em estágio mais avançado de ciclo, a soja perene também proporcionou boa cobertura de solo, redução da temperatura e retenção de umidade no solo. PALAVRAS-CHAVE: Plantas de cobertura, Adubação verde, Caatinga, Sustentabilidade. REFERENCES ALBUQUERQUE, A. W.; LOMBARDI NETO, F.; SRINIVASAN, V. S.; SANTOS, J. R. Manejo da cobertura do solo e de práticas conservacionistas nas perdas de solo e água em Sumé, PB. Revista Brasileira de Engenharia Agrícola e Ambiental, v. 6, n. 1, p. 136-141, 2002. http://dx.doi.org/10.1590/S1415- 43662002000100024 18 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 BERNARDO, S.; SOARES A. A.; MANTOVANI, E. C. Manual de irrigação. 8. ed. Viçosa: UFV, 2006. 625p. BRAGAGNOLO, L.; MIELNICZUK, J. Cobertura do solo por palha de trigo e seu relacionamento com a temperatura e umidade do solo. Revista Brasileira de Ciência do Solo, Viçosa, v. 14, n. 3, p. 369-374, 1990. EMBRAPA. Centro Nacional de Pesquisa de Solos (Rio de Janeiro, RJ). Sistema brasileiro de classificação de solos. 4rd. Ed. (E-book) Brasília: Produção de Informação, 2014. 377p. ESPINDOLA, J. A. A.; GUERRA, J. G. M.; ALMEIDA, D. L. de; TEIXEIRA, M. G.; URQUIAGA, S. Evaluation of perennial herbaceous legumes with different phosphorus sources and levels in a Brazilian Utisol. Renewable Agriculture and Food Systems, Cambridge, v. 20, n. 1, p. 56-62, 2005. http://dx.doi.org/10.1079/RAF200492 FARIA, C. M. B.; COSTA, N. D.; LEÃO, P. C. S. Adubação verde com leguminosas em videira no submédio São Francisco. Revista Brasileira de Ciência do Solo, Viçosa, v. 28, n. 4, p. 641-648, 2004. FÁVERO, C.; JUCKSCH, I.; ALVARENGA, R. C.; COSTA, L. M. Modificações na população de plantas espontâneas na presença de adubos verdes. Pesquisa Agropecuária Brasileira, Brasília, v. 36, n. 11, p. 1355- 1362, 2001. http://dx.doi.org/10.1590/S0100-204X2001001100005 FERREIRA, D. F. Sisvar: um programa para análises e ensino de estatística. Revista Symposium, Lavras, v. 6, n. 2, p. 36-41, 2008. GAMA-RODRIGUES, A. C.; GAMA-RODRIGUES, E. F.; BRITO, E. C. Decomposição e liberação de nutrientes de resíduos culturais de plantas de cobertura em argissolo vermelhoamarelo na região noroeste fluminense (RJ). Revista Brasileira de Ciência do Solo, Viçosa, v. 31, n. 6, p. 1421-1428, 2007. GUERRA, J. G. M.; ESPINDOLA, J. A. A.; PERIN, A.; TEIXEIRA, M. G.; ALMEIDA, D. L. de; ASSIS, R. L. de. Desempenho de leguminosas tropicais perenes como plantas de cobertura do solo. Seropédica: Embrapa Agrobiologia, 2007. 39p. (Boletim de Pesquisa e Desenvolvimento, 20). INMET. Instituto Nacional de Meteorologia. Disponível em: http://www.inmet.gov.br. Acesso em 10 fev. 2014. LEITE, L. F. C.; FREITAS, R. de C. A.; SAGRILO, E.; GALVÃO, S. R. da S. Decomposição e liberação de nutrientes de resíduos vegetais depositados sobre Latossolo Amarelo no cerrado Maranhense. Revista Ciência Agronômica, Fortaleza, v. 41, n. 1, p. 29-35, 2010. OLIVEIRA, F. R.; DUARTE, U.; MENEGASSE, L. N. Levantamento hidrogeológico da área de Araçuaí no médio vale do Jequitinhonha-MG. Revista Águas Subterrâneas, São Paulo, v. 16, p. 39-56, 2002. http://dx.doi.org/10.14295/ras.v16i1.1299 OLIVEIRA, C. A. P. de; SOUZA, C. M. de. Influência da cobertura morta na umidade, incidência de plantas daninhas e de broca-do-rizoma (Cosmopolites sordidus) em um pomar de bananeiras (Musa ssp.). Revista Brasileira de Fruticultura, Jaboticabal, v. 25, n. 2, p. 345-347, 2003. PERIN, A.; TEIXEIRA, M. G.; GUERRA, J. G. M. Avaliação inicial de algumas leguminosas herbáceas perenes para utilização como cobertura viva permanente de solo. II. Amendoim forrageiro, Galáxia e Centrosema. Seropédica: Embrapa Agrobiologia, 1998. 6p. (Embrapa CNPAB. Comunicado Técnico, 28). PERIN, A.; TEIXEIRA, M. G.; GUERRA, J. G. M. Desempenho de algumas leguminosas com potencial para utilização como cobertura permanente de solo. Agronomia, Seropédica, v. 34, n. 2, p. 38-43, 2000. 19 Temperature and humidity… SILVA, D. M. N. et al. Biosci. J., Uberlândia, v. 32, n. 1, p. 11-19, Jan./Feb. 2016 PERIN, A; GUERRA, J. G. M.; ESPINDOLA, J. A. A.; TEIXEIRA, M. G.; BUSQUET, R. N. B. Desempenho de bananeiras consorciadas com leguminosas herbáceas perenes. Ciência e Agrotecnologia, Lavras, v. 33, n. 6, p. 1511-1517, 2009. PRIMAVESI, A. Manejo ecológico do solo. São Paulo: Nobel, 2002. 549p. SIDIRAS, N.; PAVAN, M. A. Influência do sistema de manejo na temperatura do solo. Revista Brasileira de Ciência do Solo, Viçosa, v. 10, n. 3, p. 181-184, 1986. STRECK, N. A.; SCHNEIDER, F. M.; BURIOL, G. A. Modificações físicas causadas pelo mulching. Revista Brasileira de Agrometeorologia, Santa Maria, v. 2, p. 131-142, 1994. TORRES, J. L. R.; FABIAN, A. J.; PEREIRA, M. G.; ANDRIOLI, I. Influência de plantas de cobertura na temperatura e umidade do solo na rotação de culturas milho-soja em plantio direto. Revista Brasileira de Agrociência, Pelotas, v. 12, n. 1, p. 107-113, 2006.