Scielo RSS <![CDATA[Journal of soil science and plant nutrition]]> http://www.scielo.cl/rss.php?pid=0718-951620130004&lang=pt vol. 13 num. 4 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[Management units based on the physical properties of an Oxisol]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400001&lng=pt&nrm=iso&tlng=pt In Colombia, the zone of the greatest agricultural expansion includes soils within the native savanna system. These soils are Oxisols, which have a stable structure but are susceptible to physical degradation. The objective of this paper was to study the spatial variability of the soil physical properties with the aim of determining management units. This study was carried out in the municipality of Puerto Gaitán, Meta, Colombia, in an area of 5100 ha where nodes were placed every 320 m in a grid. The samples were taken from the surface (A H) and subsurface (B H) horizons in which the texture, pore distribution, saturated hydraulic conductivity (K S), bulk density (B D) and soil particle density (P D) were determined. The data analysis was conducted using descriptive statistics, geostatistics and multivariate analysis. The predominant textures of the soil were loam and sandy loam. High values of B D, high values of microporosity, low presence of mesopores and slow K S were found, which result in physical limitations for adequate development of crops. The B D and the total porosity were the properties that best characterized the soil and showed the greatest number of significant correlations with the other physical properties. The K S was the only property that did not show spatial dependence. Geostatistics allowed the identification of spatial variability patterns, estimation of the properties at non-sampled sites, and identification of management units of the properties that fit the semivariogram models. Multivariate analysis identified the most representative properties of the soil and permitted the establishment of management units. <![CDATA[<b>How apple responds to boron excess in acidic and limed soil</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400002&lng=pt&nrm=iso&tlng=pt Two year-old apple plants (Malus domestica cv. Red Chief Delicious) were grown in an acidic and limed soil, and fertilized with B (0, 1, 3 and 5 mg kg-1 soil). Fresh matter weight of plants was positively correlated with the applied B only in acidic soil. The number of nods, plant height, stem diameter, and shoot length were not particularly affected by either B additions or liming. The length of internodes of the plants grown in limed soil showed a positive correlation with the amount of added B, but the opposite effects were observed in the acidic soil. Boron and K concentration in leaves showed a positive correlation with added B in both soils. Leaf N and Fe concentrations were negatively affected by B additions in soils, while leaf Mn and Zn concentrations were also affected by added B and soil pH, reflecting thus their soil mobility. Chlorophyll content in leaves was reduced at high B treatments, only in plants grown in the acidic soil. Our results show that added B even in our high B-content acidic soil did not cause any detrimental effects on apple plants, and that liming seemed to buffer trace metal excesses, characteristic of any acidic soil. <![CDATA[<b>The influence of moisture on the residual effects of natural zinc chelates applied to two different soils</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400003&lng=pt&nrm=iso&tlng=pt The aim ofthis study was to compare the behavior ofresidual Zn from three natural chelates (Zn-aminolignosulfonate [Zn-AML],Zn-polyhydroxyphenylcarboxylate [Zn-PHP] and Zn-ethylenediamine disuccinate [Zn-EDDS]) applied at different rates (0, 5 and 10 mg Zn/kg soil) to a flax crop grown during the previous year. This incubation experiment was carried out over 75 days under two different moisture conditions (60% field capacity and waterlogged) in two different soils (acidic [Soil acid]and calcareous [Soil calc]). The potential available Zn concentration and short-term available Zn were estimated under both moisture conditions using the diethylenetriaminepentaacetic acid -triethanolamine (DTPA-TEA) and low-molecular-weight organic acids (LMWOAs) methods, respectively. Water-soluble Zn was estimated in both soils under 60% field capacity conditions. Immediately available Zn (the Zn concentration in the soil solution) was estimated under waterlogged conditions. The pH and Eh were also determined in both soils. Incubation of both soils under both moisture conditions led to decreases in the potential available Zn and short-term available Zn concentrations. Water-soluble Zn concentrations in soils under 60% field conditions, immediately available Zn in soils and the Eh parameter under waterlogged conditions also decreased with time. The residual effect of Zn-AML applied at a rate of 10 mg Zn/kg in Soil acid produced the highest available and short-term Zn concentrations, and the residual effect of Zn-EDDS produced the highest short-term Zn concentration in Soil calc. <![CDATA[<b>Transformation of phosphorus fractions in paddy soil amended with pig manure</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400004&lng=pt&nrm=iso&tlng=pt This paper examines phosphorus forms following application of organic fertilizer. Dynamic changes in the phosphorus fraction content were simulated by the waterlogged incubation method. This study was carried out using comparison tests between sterilized and non-sterilized treatments to analyze the effect of organic fertilizer on phosphorus form transformation. The experimental results showed that fertilization of paddy soil could significantly increase the content of the phosphorus fraction (p<0.05). Furthermore, the organic phosphorus content increased during incubation. The levels of organic phosphorus in the non-sterilized treatments were higher than in the sterilized treatments. However, the variation of the inorganic phosphorus content was contradictory. A significant correlation (r=-0.484, p<0.01) was observed between O-P and highly resistant organic phosphorus, as well as among Al-P, Ca-P, moderately labile organic phosphorus and moderately resistant organic phosphorus. Therefore, it is concluded that applying organic fertilizer can increase the content of the phosphorus fractions of paddy soil. With microorganisms present, Al-P and Ca-P can be transformed into moderately labile organic phosphorus and moderately resistant organic phosphorus, and O-P can be transformed into highly resistant organic phosphorus. <![CDATA[<b>Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400005&lng=pt&nrm=iso&tlng=pt Shear strength of aggregates and the bulk soil matrix in two Haploxeroll of central Chile was assessed in order to determine: (1) the effect of previous tillage on shear parameters between aggregates and in the soil matrix and (2) the effects of structure development on differences between dry-wet mechanical parameters. Undisturbed soil cylinders and single aggregates (0-10 cm layer) were collected from untilled and conventionally tilled sites in the Santiago (STG) and Mapocho Soil Series (MPC). General soil properties and shear parameters were determined. The shear tests were conducted on confined and free-draining aggregates and on soil cores, equilibrated at field capacity and air-dried, to obtain data on cohesion and angle of internal friction in the samples. Dry aggregates from the tilled sites showed 40 and 70% greater cohesion compared to untilled sites in STG and MPC soils, respectively, associated with a decrease in coarse porosity in the STG soil and a decrease in organic matter in the MPC soil, thus reducing its friability. In air-dried condition, aggregates from untilled sites developed 6-7 fold strength compared with soil matrix and the difference increased (9-13 fold) in samples from tilled sites. Undisturbed soil cores showed higher friction values when air-dried (68° in average, compared with 43° in individual aggregates), but at -33kPa water tension the tendency was reversed. The results of this study confirm that smaller differences between wet and dry behaviour are associated with better structural development and lower tillage intensity. <![CDATA[<b>Cadmium uptake and subcellular distribution in rice plants as affected by phosphorus: Soil and hydroponic experiments</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400006&lng=pt&nrm=iso&tlng=pt High cadmium (Cd) concentrations are a serious environmental problem in various agro-ecosystems and urban areas. Since mobile Cd in the soil can be accumulated in the food chain by plant uptake, remediation techniques to fix Cd in the soil in situ are urgently required, for which the application of phosphorus (P) is auspicious. The effects of P on soil pH, Cd phytoavailability, and Cd distribution with regard to rice plants were examined in a pot experiment using soil contaminated with 82 mg Cd kg-1. A commercial P fertilizer (0-52-34, containing 52% P2O5 and 34% K2O) was applied to the soil to reach P concentrations of 0 (the control), 50, 200, and 1000 mg P kg-1 above the baseline P concentration of the soil. P-application increased the soil pH and caused a redistribution of Cd to less mobile fractions. Plant growth was also enhanced by P addition. Plant Cd uptake was only significantly reduced in mature plants receiving a P-application rate of 1000 mg P kg-1. Additionally, a hydroponic experiment was carried out to study the effects of different P concentrations on the subcellular distribution of Cd in rice plants. When a P-application of 1000 mg L-1 was applied, the Cd proportions in the cell walls increased by 7% in the roots and 10% in the shoots, while reductions for the other fractions were observed, hinting at the occurrence of a detoxifying effect of P on the rice plant's Cd concentration. <![CDATA[<b>Effects of aluminum and moisture levels on aluminum bioaccumulation and protein content in the earthworm Octodrilus complanatus</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400007&lng=pt&nrm=iso&tlng=pt Laboratory experiments were conducted to determine the effects of soil aluminum levels and moisture content on aluminum (Al) bioaccumulation and protein content in the earthworm (Octodrilus complanatus). The experimental design was a completely randomized block with 2 factors (aluminum content [C-0: 0 mg kg-1, C-1: 1000 mg kg-1, C-2: 2000 mg kg¹־, C-3: 3000 mg kg¹־] and moisture level [M1: 100% of soil water capacity, M2: 60% of soil water capacity] and 3 replications. The lowest pH was noted in the C-0 treatment. There were no significant differences in the electrical conductivity, cation exchange capacity or total nitrogen in soil between the aluminum treatments. Moreover, there were no significant differences in soil properties between the moisture treatments. The highest soil Al content was noted in the C-3 treatment. No earthworm mortality was observed in soil contaminated with Al. Moreover, the highest aluminum content in earthworms was observed in the C-3 treatment. The aluminum content in the earthworms was significantly positively correlated with the aluminum content in the soil (r=0.984***, p<0.001). Our results indicated that the growth of earthworms was affected by the Al level. Lastly, Al caused a reduction in earthworm protein content. <![CDATA[<b>Efficacy of fresh and air-dried biosolids as amendments for remediation of acidic and metal-polluted soils: A short-term laboratory assay</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400008&lng=pt&nrm=iso&tlng=pt Biosolids have been used as amendments on mine degraded soils for in situ immobilization of metals, neutralization, and improvement of nutritional, microbiological, and physical characteristics to reestablish a self-sustaining plant community. Fresh and air-dried biosolids have been used but dried ones are preferred as they are cheaper to transport, contain less pathogens and are much easier to handle. The same efficacy has been assumed for both biosolids. The study evaluated the effects of fresh and air-dried biosolids on physical, chemical and microbiological characteristics of an acidic and metal/As-rich soil of the Puchuncaví valley, central Chile, and on plant yield under laboratory conditions. Two doses of each biosolids were used (50 and 100 ton ha-1, dry weight). Fresh and air-dried biosolids similarly increased organic matter, total nitrogen (N) and available N and phosphorous contents of study soil. However, air-dried biosolids exhibited lower field capacity and higher wilting point, salinity, higher levels of dissolved organic carbon, concentrations of total dissolved copper and zinc, and lower activity of free Cu2+ ions in pore water. Basal respiration was significantly increased by incorporation of biosolids into soils, irrespective of being fresh or air-dried ones. In terms of aerial plant productivity, fresh biosolids and low doses of air-dried biosolids significantly increased this characteristic. However, high doses of air-dried biosolids limited aerial biomass and root cover, probably due to soil salinity and water stress. Therefore, fresh biosolids are suggested for remediation of this mine degraded soils. <![CDATA[<b>Crop yield, P uptake and soil organic phosphorus fractions in response to short-term tillage and fertilization under a rape-rice rotation in central China</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400009&lng=pt&nrm=iso&tlng=pt We conducted a 3-year field experiment on an Anthrosol paddy soil to investigate changes in crop yield, P uptake and soil organic phosphorus (P) fractions after 3 years of conventional tillage (CT) conversion to no-tillage (NT) under a rape - rice rotation in central China. Treatments were established following a split-plot design of a randomized complete block with tillage practice as the main plot and fertilizer as the sub-plot treatment. The yields of rape and rice ranged from 1378 to 2264 kg ha-1 and from 5895 to 9453 kg ha-1 across 3 years, respectively. Moreover, P uptake for rape and rice (aboveground) varied from 3.9 to 10.4 kg ha-1 and from 9.5 to 32.0 kg ha-1, respectively. Fertilization significantly enhanced crop yields and P uptake, but tillage did not affect the yields and P uptake. Fertilization significantly increased total P concentrations, acid phosphatase activity, Bray-1 P and labile organic P in the 0-5 cm soil layer. Compared to the CT treatments, the NT treatments had significantly higher acid phosphatase activity, total P, Bray-1 P, total organic P and organic P fractions in the 0-5 cm soil layer but lower organic P fractions in the 5-20 cm soil layer. Therefore, our results suggest that short-term NT does not enhance organic P concentrations in the 0-20 cm soil layer, and only improve P availability on the soil surface. <![CDATA[<b>Organic carbon density and storage of the major black soil regions in Northeast China</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400010&lng=pt&nrm=iso&tlng=pt Black soils in the Northeast Plain of China are characterized by high organic carbon (C) density and storage, which can influence C sequestration in local cropland ecosystems. Using GIS, this study analyzed the temporal and spatial distribution and variation of cropland organic C density and storage in the arable layer (0-20 cm) of the major black soil regions in China's Northeast Plain (specifically across the study region of Hailun, Shuangcheng and Gongzhuling counties) over the past 30 years. The results indicate an overall downward trend in soil organic C (SOC) density (SOCd, mean decrease of 0.64 kg m-2) and storage (SOCs, decrease of 4.65 Tg )*1 for the major black soil regions tested during the study period. The mean decrease in SOCd for Hailun, Shuangcheng and Gongzhuling counties was 0.68 kg m-2, 0.18 kg m-2 and 1.05 kg m-2, respectively, with total SOC decreases of 2.30 Tg, 0.49 Tg and 1.86 Tg, respectively. SOCd decreased to a greater extent during the first twenty years in Hailun and Shuangcheng relative to Gongzhuling. Moreover, SOCd tended to stabilize and then slightly increase during the last ten years. There was a downward trend in SOCd and SOCs over the past 30 years for almost all soil types, but the most serious decline in SOCs was observed in black soils, which account for 57.92% of the cropland soil area in all study regions and which lost up to 2.91 Tg of SOC. Therefore, the major black soil region in Northeast China was presenting a C resource trend over the past 20-30 years. <![CDATA[<b>Influence of fertilizer placement on yield and protein composition in spring malting barley</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400011&lng=pt&nrm=iso&tlng=pt Soil type and starter fertilizer treatments are known to influence yield, grain protein concentration and grain protein composition in malting barley (Hordeum vulgare L.). Combi drilling of spring sown cereal crops has become more popular recently. Depending on the type of combi drill coulter, the fertilizers are placed differently in relation to the seed (e.g. below or beside) and the placement might influence the nitrogen availability. Thus, the aim was to evaluate if and how fertilizer placement by using different coulter types, influenced grain yield, protein concentration and protein composition in spring malting barley. Fertilizer placement beside and deeper than the sown seed (Vaderstad Rapid Combi coulter) resulted in increased emergence (15%) 20 days after sowing, and increased yield at normal seed rate compared to when the fertilizer was placed just below the sown seed (Tume Nova Combi coulter). Fertilizer placement just below the sown seed led to an increased protein polymerisation compared to fertilizer placement beside and deeper than the sown seed. Nitrogen fertilization led to an increased yield, grain protein concentration, amount of SDS-extractable and -unextractable proteins and small monomeric proteins compared to no nitrogen fertilization. To conclude, nitrogen rate correlated positively with amount of most protein types, while close placement/ availability of nitrogen correlated with protein polymerisation. For grain yield, fertilizer placement just below the sown seeds was negative. Thus, placement of nitrogen might influence the quality of the barley grain for malting purposes. <![CDATA[<b>A review of zinc nutrition and plant breeding</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400012&lng=pt&nrm=iso&tlng=pt Plants require the proper balance of zinc (Zn) for normal growth and optimum yield. Interest in Zn has risen in the last decade because Zn deficiency stress is extensive in many areas, causing decreases in crop yields. Zn deficiency also decreases the amount of Zn in cereal grain and diminishes its nutritional quality. Hence, increasing the Zn content of the edible portions of crops should be considered in plant breeding. Available data indicate that Zn enrichment traits are present within the genomes of crops that could allow for substantial increases in the Zn concentration of edible parts without negatively impacting yield. Increasing the amount of Zn in food crops can improve the Zn status of people. Furthermore, the use of Zn-dense seeds results in greater seedling vigor and increased crop yields when the seeds are sown in Zn-poor soils. Progress toward developing mineral-dense seed has mainly relied upon conventional plant breeding approaches, a process that is labor-intensive and time-consuming. Hence, the identification of DNA markers that are diagnostic of Zn efficiency can accelerate the development of cultivars that can remain productive even in Zn-deficient soils. Additionally, these markers may be used to begin identifying the specific genes responsible for differences in the response of genotypes to Zn deficiency. <![CDATA[<b>Roles of exogenous nitric oxide in regulating ionic equilibrium and moderating oxidative stress in cotton seedlings during salt stress</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400013&lng=pt&nrm=iso&tlng=pt Using a potted experiment, we studied the effect of slow-release nitric oxide (NO) on the physiological characteristics of cotton seedlings subjected to salt stress (585 mg/kg NaCl). Sodium nitroprusside (SNP, an NO donor, 2.62 mg) was applied either directly to the soil, via slow release methods (slow-release bags, slow-release capsules, or slow-release particles), or via foliar application. NaCl decreased plant weight and chlorophyll content and increased electrolyte leakage and the contents of proline, ascorbic acid (ASA), and Na. NaCl also induced oxidative stress, as indicated by elevated levels of lipid peroxidation and ROS production. Foliar spray of SNP (0.09 mM) enhanced plant growth, promoted ion absorption and transport, and increased enzyme activity. Slow-released NO increased the levels of chlorophyll, ASA, and proline; promoted the uptake of K, Ca and Mg; and decreased Na. Moreover, increases in SOD and CAT activity were demonstrated to counter oxidative stress. However, different methods of SNP application have different effects on salt-tolerance. Foliar application was optimal. Slow-release NO, especially slow-release particles, was better able to alleviate NaCl toxicity compared with direct application of NO to the soil. <![CDATA[<b>Nutrient availability in the rhizosphere of rice grown with plastic film mulch and drip irrigation</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400014&lng=pt&nrm=iso&tlng=pt The combined use of plastic film mulch and drip irrigation for rice production could result in high yields and significant water savings. However, little is known about soil nutrient availability in this system. The objective of this laboratory experiment was to measure the availability of soil N, P, K, Zn, and Mn in two treatments: (i) conventional flood irrigation (FI) and (ii) plastic film mulch and drip irrigation (PFM-DI). Rice (Oryza sativa L. cv T-04) was sown in plastic boxes containing 80 kg soil. Bulk and rhizosphere soil samples were collected at four growth stages (i.e., tillering, jointing, full heading, and grain filling). Soil NH4-N and exchangeable Mn concentrations were lower in the PFM-DI treatment than in the FI treatment. In contrast, concentrations of NO3-N, available K, available Zn, and easily reduced Mn were higher in the PFM-DI treatment than in the FI treatment. There was no significant difference in Olsen P between FI and PFM-DI treatments. Soil NH4-N, available K and exchangeable Mn concentrations were lower in rhizosphere soil than in bulk soil. In contrast, NO3-N and Zn concentrations were higher in rhizosphere soil than in bulk soil. Neither available P nor easily reduced Mn concentrations differed between rhizosphere and bulk soil. Our results indicated that compared with conventional flood irrigation, the plastic film mulch plus drip irrigation system increased soil nutrient availability. <![CDATA[<b>Microbial biomass, nutrient availability and nutrient uptake by wheat in two soils with organic amendments</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400015&lng=pt&nrm=iso&tlng=pt A 72-day greenhouse pot experiment was conducted with a sandy loam or a silt loam soil to examine the effects of farmyard manure (FYM), poultry litter (PL) and biogenic waste compost (BWC) at 10 g dw kg-1 soil on microbial biomass and activity and growth and nutrient uptake by wheat. Soil samples were collected at days 0, 14, 28, 42, 56 and 72 after planting. Growth and nutrient uptake by wheat were determined on day 72. All three amendments increased microbial biomass C, N and P, dehydrogenase activity, plant growth and nutrient uptake with a greater effect by FYM and PL than by BWC. All amendments increased microbial biomass C, N and P and enzyme activity particularly on day 0. These microbial parameters decreased after day 0 indicating microbial biomass turnover. All amendments increased plant growth and nutrient uptake. It is concluded that organicamendments can stimulate microbial growth and nutrient uptake as well as plant growth and nutrient uptake. Microbes can increase plant nutrient availability by nutrient mobilisation but also because nutrients taken up by the microbial biomass initially could become available to plants when the microbial biomass turns over as the easily available C is depleted. <![CDATA[<b>Oxytetracycline on functions and structure of soil microbial community</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400016&lng=pt&nrm=iso&tlng=pt Effects of oxytetracycline (OTC) on soil enzyme activity and structural diversity of soil microbial communities were investigated. The low and moderate OTC inputs of less than 15 mg/kg enhanced microbial growth and increased the total and bacterial and fungal biomasses in the receiving soils. The antibiotic toxicity of OTC although targeted the bacteria in the soils proportionally resulted in greater harmed against the soil fungi than the bacteria and the Gram-negative bacteria fared significantly better than the Gram-positive bacteria. Collectively, the high OTC inputs lowered of soil enzymatic activities and the low and moderate OTC inputs did not have any adverse impact on the soil enzyme activities. <![CDATA[<b>Nutrient partitioning among the roots, hedge and cuttings of Corymbia citriodora stock plants</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400017&lng=pt&nrm=iso&tlng=pt Many eucalypt species are difficult to propagate as rooted cuttings. The mineral nutrition of cuttings is a key factor that limits adventitious root induction but little is known about partitioning of nutrients by eucalypt stock plants. This study determined N, P, K, Ca, B, S, Mg, Mn, Zn, Al, Fe and Na concentrations in the root system, pruned hedge and harvested cuttings of stock plants of the eucalypt, Corymbia citriodora. Between 17% and 31% of total plant mass was collected as cuttings at each harvest. The mobile nutrients, N, K and S, were highly concentrated in the cuttings and were removed in high amounts (e.g. 27-6%> of total plant N) at each harvest, whereas less-mobile nutrients such as Ca and Zn were less concentrated in the cuttings than other plant parts. Adventitious rooting of eucalypt cuttings has been related to B concentration but this study revealed that B was much more highly concentrated in the hedge than the cuttings. Management of N and K concentrations for shoot production, and B concentrations for adventitious rooting, may be critical for sustaining rooted cutting production by C. citriodora. <![CDATA[<b>Effects of biochar amendment on soil aggregates and hydraulic properties</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400018&lng=pt&nrm=iso&tlng=pt The aim of this study was to investigate the effects of biochar amendment on soil aggregate formation and stability, and soil hydraulic properties. Biochar produced from dairy manure was added to two different soils (a silty clay and a sandy loam soil) at a ratio of 2% (w/w in dry weight basis). Incubation experiments were conducted within a 90-d period with the soils (the controls) and the soil/biochar mixtures. Compared with the controls, biochar addition significantly enhanced the formation of macroaggregates and slightly increased saturated hydraulic conductivities of the soils. Attributable to the soil structure change, saturated water contents increased and residual water contents decreased with the biochar amendment. These changes with biochar addition greatly affected the shape of soil water retention functions. For both the soil aggregate formation and the change of soil water retention curves, the sandy loam soil was more sensitive than the silty clay soil to the biochar application on all sampling days. The information from this study should be useful to better understand water processes in the soil with biochar application. <![CDATA[<b>Effects of organic-matter application on phosphorus adsorption of three soil parent materials</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400019&lng=pt&nrm=iso&tlng=pt In this study, poultry manure compost and organic fertilizer were added to soils derived from basalt, granite, and river alluvial deposits for use as soil parent materials. Following incubation periods of 30 or 60 days at 25 °C, the physical and chemical properties and adsorption characteristics of the soils were studied. The results indicated that the application of poultry manure compost or organic fertilizer increased the available phosphorus (P) and organic matter content in all soils; however, the quantity of P and organic matter decreased with an increase in incubation time. The organic materials added via the treatments reduced the strength of P adsorption by the soil derived from basalt. For soils derived from granite and river alluvial deposits, the strength of P adsorption declined after poultry manure compost was added, but increased after the application of organic fertilizer. All soil treatments derived from basalt fitted well with the three adsorption isotherm equations. For soils derived from granite and alluvial deposit as parent materials, the data conformed to the three adsorption models in the order: Langmuir > Freundlich > Temkin. The maximum phosphate buffering capacity (MPBC) and standard P retention (SPR) of soil derived from basalt decreased following the application of poultry manure or organic fertilizer, whereas changes in MPBC and SPR for soils derived from granite and alluvial deposits were dependent on the organic content and incubation time. <![CDATA[<b>The effects of soil salt crusts on soil evaporation and chemical changes in different ages of Taklimakan Desert Shelterbelts</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400020&lng=pt&nrm=iso&tlng=pt Understanding soil evaporation in reforestation processes in an area of extreme drought is important. We examined the effects of drip-irrigated, high-salinity groundwater on the formation of soil salt crusts and subsequent soil evaporation in the Taklimakan Desert Highway Shelterbelt. Soil evaporation was measured using micro-lysimeters (MLS, 20 cm in length x 10 cm in diameter), and chemical characteristics, including SOM, total salts, ion composition and pH, were analyzed. The results showed that the inhibition efficiency of salt crusts on soil evaporation decreased from the surface to the lower soil layers. Following irrigation, the inhibition efficiency was 33.0% in the shelterbelt, which was much higher than the 13.8% observed for the bare soil. Total salt content and ion contents (Cl¾, Na+, and SO4²>) were much higher for the soil salt crusts than for shifting sandy soils, while the contents of other ions (Mg²+, K+, Ca²+, HCO3>, and CO3²>) were very similar. The total salt content and ion composition of the salt crusts increased during the first 2 years of shelterbelt age, and decreased from 2 to 5 years. With the increasing age of the shelterbelts, the SOM of the salt crusts increased, whereas the total salts and pH decreased. We concluded that the formation of soil salt crusts results in reduced soil evaporation and the soil chemical condition functioned better for growth of the Taklimakan Desert Highway Shelterbelt.