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Effect of soil compaction on root growth and crop yield in Central and Eastern Europe
Lipiec J.,Medvedev V.V.,Birkas M.,Dumitru E.
International Agrophysics , 2003,
Abstract: Variations in root growth and functions in response to soil compaction associated with soil and crop type, and soil wetness at the time of load application and weather in Central and Eastern Europe are reviewed. The effects of soil compaction on the morphological and anatomical modifications of the roots were shown. The influence of soil compaction on plasticity in root growth and functioning in relation to structural discontinuity is discussed. Possible mechanisms of root-shoot relations as affected by soil compaction are presented. Crop yields on compacted soil largely depend on weather conditions and initial soil compactness.
Cenosis structure and species composition dynamics of micromycetes decomposing crop root residues in soil
Z. Kriau iūnien , R. Veli ka , M. Rimkevi ien , R. Pupalien , O. Salina
Biologija , 2008, DOI: 10.2478/v10054-008-0008-6
Abstract: Experiments on the decomposition of crop residues were carried out at the Experimental Station of the Lithuanian University of Agriculture (54°53'N, 23°50'E) in a model field in 2004-2006. The soil of the experimental site is Endocalcari-Epihypogleyic Cambisol (sicco) (CMg-p-w-can). We investigated root residues of winter oilseed rape (Brassica napus L. ssp. oleifera biennis Metzg.), spring oilseed rape (Brassica napus L. ssp. oleifera annua Metzg.), winter wheat (Triticum aestivum L.), and red clover (Trifolium pratense L.) decomposed in soil for different time (7.5, 14.5, 19.5, and 26.5 months). The aim of the investigation was to establish in soil decomposed winter and spring rape root micromycetes community structure and species composition dynamics in comparison with winter wheat and clover roots. It has been established that on the decomposed crop roots micromycetes spread depended first of all on the plant species. Most of micromycetes colony forming units were found on red clover roots, less on rape roots and least on winter wheat roots. The micromycetes colony forming unit number depended on root decomposition (according to correlative-regressive analysis a positive strong and very strong correlation) and on the decomposed substrate C: N ratio (a strong and very strong negative correlation). A specific character of the genus Trichoderma fungi species spreading depending on the nature of crop roots has been established. For the first time in Lithuania the following species have been identified: T. longibrachiatum - on winter and spring rape, T. aggressivum f. europaeum - on winter rape, T. spirale - on spring rape, winter wheat and clover, T. crassum - on winter wheat and winter rape, T. brevicompactum - on winter wheat roots. On the decomposed rape roots Trichoderma micromycetes producing antibiotics were prevailing (T. harzianum, T. aggressivum f. europaeum, T. viride, T. hamatum and others) and limited the development of conditionally phytopathogenic Fusarium, Rhizoctonia, Penicillium, Alternaria and other fungi. In all periods of study, on rape roots the number of Fusarium species was lower than on clover or wheat roots. Thus, Trichoderma fungi abundance on rape residues, rape root chemical composition and the peculiarities of their fragmentation products are important factors influencing the phytosanitary state of soil.
Optimum matching between soil infiltration body and crop root system under trickle irrigation

ZHANG Miao-Xian,

中国生态农业学报 , 2005,
Abstract: The optimum match ing between soil infiltration body and c rop root system under trickle irrigation shows that the soil infiltration body i s the intermediate effect region between trickle irrigation system and crop root system and the reasonable matching betw een soil infiltration body and crop root system is one of the keys to raising tr ickle irrigation system efficiency.
Root growth characteristics of different leguminous crop in degraded grassland soil

- , 2016,
Abstract: 以退化草地土壤为供试基质,采用盆栽和网箱栽培方法,研究大豆、黑大豆、绿豆、豌豆和蚕豆根系生长特征。结果表明:不同豆科作物根系各项指标的增长随生育期变化的时间趋势基本呈"S"型增长模型,可划分为缓增期、速增期、顶峰期和衰减期 4 个时期;不同豆科作物根系垂直分布的深浅存在较大差异,根系生物量空间呈"T"型分布,其垂直递减率符合幂曲线模型Y=B0·XB1。综合试验结果,黑大豆、蚕豆和大豆比绿豆和豌豆更适合在该试验条件下种植,其中黑大豆和蚕豆可以作为该类型土壤首选作物。本研究结果为选择适宜的豆科作物进行合理种植达到改良退化草地土壤、提高退化草地生物量产出提供了依据。
The root-growth rhythm of different leguminous crops including soybean, black soybean, mung bean, pea, and broad bean in degraded grassland soil was studied by pot culture and rebar chain link mesh box cultivation methods.The results showed that:The root growth index of different leguminous crop followed an "S"-shaped growth model which classified as slow-increased period, rapid-increased period, peak period and decline period;Vertical distribution of roots had significant difference for all tested leguminous crops and the biomass of root system showed "T" shaped distribution model for vertical depth and root biomass followed the power curve model of decreasing successive reduction (Y=B0·XB1).According to the result of the study, it was found that black soybean, broad bean and soybean were more suitable for planting in the experimental conditions than mung bean and pea, among them, the black soybean and broad bean were preferred crops for this type of soil.This study provided a theoretical basis for the selection of suitable legume crops to improve the degraded grassland soil and increase the output of degraded grassland biomass.
Soil water extraction by roots and Kc for the coffee crop
Silva, Adriana L. da;Bruno, Isabeli P.;Reichardt, Klaus;Bacchi, Osny O. S.;Dourado-Neto, Durval;Favarin, José L.;Costa, Flávio M. P. da;Timm, Luis C.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2009, DOI: 10.1590/S1415-43662009000300006
Abstract: basic information for a rational soil-water management of the coffee crop is still insufficient, particularly under irrigated conditions. of great importance for the estimation of water requirements of coffee crops are their root distribuition and evapotranspiration crop coefficients. this study compares soil water extraction by roots of coffee plants of the variety "catuaí vermelho" (iac-44), grown in piracicaba, sp, brazil, 3 to 5 years old, with direct measurements of root dry matter, showing a good agreement between both approaches, and confirming that most of the root system is distributed in the top soil layer (0-0.3 m) and that less than 10% of the root system reaches depths greater than 1.0 m. calculated evapotranspiration crop coefficients are in agreement with those found in the literature, with an average of 1.1, independent of shoot dry matter, plant height and leaf area index.
Impacts of soil structure on crop growth
Rajkai K.,V????gh K.R.,V????rallyay G.,Farkas C.S.
International Agrophysics , 1997,
Abstract: Intensive agricultural utilisation of soils may change the structural status and through it the credibility and fertility of soils. Since soil structure has not been quantified explicitly, studying structure-related soil phenomena is still actual. The goal of the present study was to apply field measurements on structure related soil hydrophysical properties and to study their mutual effect on crop growth. Near hydraulic water conductivity, bulk density, water retention characteristics of soils were measured in a wheat and a maize field as well as the soil water content dynamics during the vegetation period. Simulation models (SOIL and SOILN) were applied for studying different effects of soil structural status on winter wheat and maize crop's developments and on yields. Simulation results showed that water limitation in fields having normal and high bulk density topsoil developed gradually. In the low bulk density field case, water limitation on crop growth is noticeable almost from the beginning of crop growth. Though the combined effects of soil water stress and rooting due to soil structure resulted in marked differences in simulated yields, the effect of the saturated water conductivity and bulk density on the crop yield alone proved to be non significant. However, when a consequence was introduced regarding the plant root distribution, which differs in different soil physical conditions, a strong effect on the crop's growth was detected. This finding demonstrates the complex nature of the phenomenon called structural status of soil, and it definitely requires further research.
Leaching Requirements to Prevent Soil Salinization  [PDF]
Tekin Kara,Lyman S. Willardson
Journal of Applied Sciences , 2006,
Abstract: The purpose of this study was to develop a model to quantify the rate of upward water movement from a shallow water table for different soils with and without plants as a function of water table depth and time, to predict Electrical Conductivity (EC) of the soil in a one-dimensional homogenous soil profile and to develop a water management procedure to control soil profile salinity in the presence of a shallow water table. The model simulates water and solute movement from a shallow water table for a bare soil surface. Salt distribution in the soil profile, caused by a saline shallow water table, was simulated by assuming a steady state upward water movement in the absence of a crop. As water moves upward through a soil profile from a shallow water table, the water evaporates at the surface, leaving the salt behind. Some of the salt moves down to a depth about 30 cm by molecular diffusion. This raises the salt concentration within the top 30 cm of the soil. The model also simulates crop water extraction patterns and consequently the salt distribution patterns in an irrigated soil profile for a specified root distribution. After a fallow season and the resulting salt concentration near the soil surface, the salt redistributes downward because of irrigation water application. Different leaching fractions were used in the simulations. A computer program, for the model SALTCTRL (Salt Control), was written in QBASIC language. The program was tested for two soils for different leaching fractions. The soil parameters needed for the computations were selected from the literature. Application of model results is discussed and recommendations for further research were made.
Physical model for movement of water in split-root wheat plants
Kirkham M.B.,Erickson P.I.
International Agrophysics , 1997,
Abstract: Roots can be split between soil and nutrient solution to determine the effect of soil matric potential on water relations. When such experiments are done with wheat, water from the nutrient solution side moves to the soil side and keeps it wet. Wheat grown with roots split between soil and nutrient solution grows taller than wheat with roots split between soil and soil or between nutrient solution and nutrient solution. A physical model, based on Darcy's law and an Ohm's-law analogy, is used to explain the movement of water between the roots. The model shows that the direction of water flowing in each part of a split-root system depends upon the total head for the stem, crown, and each half of the root. In practice, a root split between soil and nutrient solution acts as a wick and draws solution from the solution side to the soil side of the system. At the crown, the flow of the solution splits, and part of the solution goes up to the shoot and part goes down to the roots in soil. Nutrients feed the roots and shoots. As long as the roots can wick over the nutrient solution into the soil, the plants thrive. Such a split-root system might be realized under furrow-dike irrigation in the field, where part of a root might be in soil and part in water with fertilizer. The model permits the estimation of a crown water potential, which determines the direction of water movement (down to root in soil and/or up to shoot). The crown water potential can be used to compare culti-vars and treatments.
The simplified model of salt-water regimes in farm land soil under the processing of evaportranspiration

ZHANG Miao- Xian,MAO Ren-Zhao,

中国生态农业学报 , 2003,
Abstract: According to the principle of salt-water balance and the observation and experimental data about ground water, irrigation and salt regimes, making use of water-need coefficient and transpiration coefficient and introducing salt and water migration coefficients, this paper presents a simplified model of salt-water regimes of upper soil layer under the processing of evapotranspiration. Based on the growth function of the crop roots, a water uptake ratio coefficient of crop roots is presented also, so that divide the lower boundary water flow into root extraction and soil capillary water movement. Introduced salt modified coefficient to evapotranspiration and feedback with the salt and water production function, evapotranspiration and the salt-water regime model are modified. The model is simple and suitable for the regulation and control of water and salt regimes on farmland under the processing of evapotranspiration.
Rodrigo Fascin Berni,Pedro Marques da Silveira,Jefferson Luís da Silva Costa
Pesquisa Agropecuária Tropical , 2007, DOI: 10.5216/pat.v32i2.2408
Abstract: As podrid es radiculares do feijoeiro s o causadas pelos fungos Rhizoctonia solani Kühn e Fusarium solani f. sp. phaseoli Snyd. & Hans. Neste trabalho testou-se a combina o dos fatores preparo de solo e rota o de culturas, além de se avaliarem seus efeitos sobre as podrid es radiculares do feijoeiro. Os tipos de preparo de solo consistiram em: arado+grade (P1), arado (P2), grade (P3) e plantio direto (P4). As rota es de culturas foram: arroz-feij o (R1), milho-feij o (R2), arroz/calopog nio (Calopogonium muconoides)-feij o (R3) e milho-feij o-milho-feij o-arroz-feij o (R4). A severidade de F. solani f. sp. phaseoli, avaliada aos 25 dias após o plantio, apresentou intera o significativa, sendo a maior severidade encontrada na combina o da rota o R3 com o preparo de solo P1, e a menor severidade, na combina o da rota o R2 com o preparo de solo P3. Diferen as estatísticas ocorreram na severidade da doen a provocada por R. solani. O preparo de solo P3 apresentou maior severidade que P4, e, entre as rota es, R3 apresentou a maior severidade da doen a. PALAVRAS-CHAVE: Rhizoctonia solani; Fusarium solani f. sp. phaseoli; práticas culturais; fungos. Dry bean root rot is caused by the fungi Rhizoctonia solani Kühn and Fusarium solani f. sp. phaseoli Snyd. & Hans.The effects of the interaction between soil tillage systems andcrop rotation on the severity of root rot was tested. The soiltillage systems consisted of plough+harrow (P1), plough (P2),harrow (P3) and no tillage (P4) and the crop rotation treatmentswere rice-bean (R1), corn-bean (R2), rice/Calopogonium muconoides-bean (R3) and corn-bean-corn-bean-rice-bean (R4). The severity of F. solani f. sp. phaseoli was evaluated 25 days after planting. The interaction was significant for this variable. The higher severity was under R3 with soil tillage system treatment P1. The lowest severity was under interaction R2 with soil preparation P3. Significant differences were found in the severity of the disease caused by R. solani. Soil tillage system P3 presented significantly higher disease severity than P4, whereas rotation R3 presented significantly higher disease severity when compared to other treatments. KEY-WORDS: Rhizoctonia solani, Fusarium solani f. sp. haseoli; cropping practices; fungi.
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