Maximum Water Retention Capacity Research Articles

Differential Water Conservation Capacity in Broadleaved and Mixed Forest Restoration in Latosol Soil-Eroded Region, Hainan Province, China.

The water conservation capacity of the litter and soil layers of forest ecosystems improves the function of forest ecosystems in conserving soil and water. Plantation restoration plays a key role in preventing soil erosion. In order to evaluate the water conservation capacity of plantation restoration in Latosol soil-eroded region, we analyzed the litter thickness and mass, water absorption process, water holding recovery process, and soil water holding capacity of five restoration types (Hevea brasiliensis, Acacia mangium, Eucalyptus robusta, Acacia-Eucalyptus, and Acacia-Hevea) in the Mahuangling Watershed, Hainan province. The results showed that the thickness of the litter ranged from approximately 3.42 ± 0.24 to 4.73 ± 0.81 cm, and the litter mass ranged from 5.04 ± 1.52 t·ha-1 to 13.16 ± 1.76 t·ha-1, with higher litter mass in the SL layer than in the UL layer. The litter mass of A. mangium was higher than that of H. brasiliensis, E. robusta, Acacia-Eucalyptus, and Acacia-Hevea, which was 3.16 ± 1.76 t·ha-1. A. mangium forest was significantly higher than other plantation restoration types in terms of the maximum water retention capacity (Qmax) and the effective water retention capacity (Qeff). The soil bulk weight ranged from approximately 1.52 ± 0.09 to 1.59 ± 0.08 g·cm-3, and porosity ranged from 31.77 ± 4.72 to 35.62 ± 3.02%, both of which increased with the depth of the soil layer. The water holding capacity of 0-60 cm soil varied from approximately 12.94 ± 7.91 to 45.02 ± 31.79 t·ha-1, with A. mangium having the best soil permeability and the strongest soil water holding capacity. The entropy weight method was used to conduct a comprehensive evaluation, and the results showed that the water conservation capacity of the soil layer was 1.26 times higher than that of the litter layer, in which the water conservation capacity of A. mangium was the strongest, with a comprehensive evaluation value of 0.2854, which effectively intercepted rainfall and reduced surface runoff. Hence, we suggest that the planting of A. mangium should be considered in future ecological restoration projects of the erosion area of Mahuangling in order to improve the function of conserving soil and water in a restoration forest ecosystem.

Statistical Analysis of the Physico-Chemical Characterization of Three Arid Soils in the Hadjer-Lamis Region, Chad

The aim of this study is to carry out a physico-chemical characterization of three arid soils. Soil samples were taken from a horizon of 0-20 cm and analyzed as follows: texture, electrical conductivity, maximum water retention capacity and natural moisture content were determined at the Laboratory of Soils-Water-Plants (LASEP) in Chad. On the other hand, the organic matter rate, soil reaction, total and assimilable phosphorus, total nitrogen, total potassium, CEC, exchangeable bases, and C/N ratio were determined at the National Soil Office (BUNASOL) in Burkina Faso. XLSTAT software version 7.5.2 was used for this work, and tests for comparison of means were carried out using the Fischer method with a threshold of 5%. The results of these analyses give for each soil in this order (% clay, % silt, % sand), Dandi (19.5%, 17.5%, 63%), Karal (17%, 7.5%, 75.5%) and Mani (14%, 7%, 79%), all these three soils have a sandy-silty texture. The organic matter levels obtained overall are low: Dandi (0.68 mg/100 g dry matter), Karal (0.61 mg/100 g dry matter), Mani (0.61 mg/100 g dry matter), these results confirm the aridity of these soils. Total phosphorus levels in Dandi, Karal and Mani are 182.50 mg/100 g, 265.50 mg/100 g and 388 mg/100 g dry matter respectively, while assimilable phosphorus levels are 13.08 mg/100 g, 42.33 mg/100 g and 18.10mg/100g dry matter respectively. The three soils have a slightly basic pH-water: Dandi (8.07), Karal (7.29), Mani (7.03) as for the pH-KCl, they are as follows: Dandi (6.28), Karal (6.33) and Mani (6.03). Soil C/N ratios vary from 7.83 to 17.05, CEC from 12.82 to 23 meq/100 g, electrical conductivity from 160.50 to 666.50 µS/cm and maximum water retention capacity from 34.66 to 45.22%. Moisture levels ranged from 2.77 to 4.40% and saturation levels were Mani (19.50%), Dandi (41.09%) and Karal (53.43%). The sum of the bases, meanwhile, varies as follows Dandi (1205.55 mg/100 g dry matter), Mani (2094.68 dry matter) and Karal (2162 mg/100 g dry matter). The total potassium obtained in each of the soil samples is as follows: Dandi (480.50 mg/100 g of dry matter), Karal (483 mg/100 g of dry matter) and Mani (325 mg/100 g of dry matter) and finally, the total nitrogen content varied from 0.02 to 0.04 mg/100 g of dry matter.

Water Availability Influences Soil Liming for the Tropical Grasses Implantation

ABSTRACT Limestone needs to react with water to correct the soil acidity. Therefore, it is expected that soil water availability interferes with limestone reaction time. The objectives of the study were (1) verify whether soil water availability alters limestone reaction time and (2) to evaluate whether the period of less than 60 days between limestone incorporation and sowing is sufficient to correct soil acidity. Two trials were carried out in a greenhouse, in a completely randomized design, in a factorial scheme. In the first trial, the BRS RB331 Ipyporã grass was grown, and the soil was subjected to the combination between the number of times the soil was raised to the maximum water retention capacity (1, 2, 3 and 9 irrigation) and two base saturation (50% and 60%). In the second trial, the Panicum maximum cv. Mombasa was grown, and six treatments were adopted in a 3 × 2 factorial scheme, consisting of the combination of three levels of water availability (50%, 75% and 100% from maximum water-holding capacity) and two limestone reaction periods (30 and 60 days). Soil water availability significantly influenced the limestone reaction time. As a result, it is possible to implant Mombasa and BRS Ipyporã grasses after 30 days of limestone incorporation, provided that the water saturation in the soil is increased to 75%.

Reactivity of two acidity correctives in a medium texture soil

For crops to have good productivity, it is necessary to adopt agricultural practices that ensure an adequate supply of water and nutrients, and neutralize toxic elements in the soil, especially exchangeable aluminum, both in the arable layer and in the subsurface. One of these agricultural practices usually employed in both small and medium and large rural properties is the correction of soil acidity, which aims, in addition to neutralizing exchangeable aluminum, to provide calcium and magnesium for plants. Several materials have been used to correct soil acidity, with carbonates, oxides, hydroxides or silicates as neutralizing components. In the present work, the reactivity of two acidity correctives was evaluated in a soil of medium texture, with high aluminum saturation: 72.96%. The correctives used were a steel slag (calcium silicate), and a dolomitic limestone, applied in doses equivalent to one, one and a half, two, and two and a half times the analytically predicted amount, to raise the base saturation to 60%, using calcium acetate with H+ + Al3+ extractor. The study also included a control treatment, which did not receive acidity correction. The method used to evaluate the reactivity of the two correctives was soil incubation. The block design was used, with six repetitions per concealer dose. The experimental units were plastic bags with 3.0 kg of soil. After mixing the correctives with the soil, in the doses corresponding to each treatment, they were transferred to plastic bags and incubated at 70% of the maximum water retention capacity for ninety days. After the incubation period, the soil was analyzed for pH in CaCl2, pH in H2O, exchangeable aluminum (Al+3), and base saturation (V %). Steel slag and dolomitic limestone had the same efficiency to neutralize aluminum and increase base saturation. The pH in CaCl2 and pH in H2O were highly correlated, with the average pH in H2O being 0.50 units greater than the pH in CaCl2. The equation to relate pH in CaCl2 to pH in H2O was Y= 1.0273 x + 0.4716, with R2 = 0.9730. Complete neutralization of Al+3 occurred when the soil pH was raised to 5.03 (pH in CaCl2) or pH 5.50 (pH in H2O). The extraction of H+ + Al3+ with calcium acetate resulted in an underestimation of the cation exchange capacity at pH 7.0 (CTC T), and consequently of the corrective dose to be applied. On average, there was a need to double the amount of concealer predicted analytically to reach the desired base saturation. The equation to relate base saturation with corrective doses, in CaCO3 equivalents, was Y= 9.1476x + 3.8439, with R2 of 0.9449.

Hydrological Properties of Soil and Litter Layers of Four Forest Types Restored in the Gully Erosion Area of Latosol in South China

Litter and soil play an important role in influencing hydrological processes and the global water cycle. Artificial afforestation, as a part of vegetation restoration, was constructed in the gully erosion areas of latosol with the objective to prevent erosion. Variations in the hydrological properties in soils that have undergone vegetation restoration from gully erosion are not well understood. In this study, we examine the variations in the litter thickness and mass, soil structure and porosity, and hydrological properties of four forest types (eucalyptus–grass forest, bamboo–grass forest, acacia–grass forest, and shrub–grass forest). The results show that the total litter thickness varied from 1.71 to 3.74 cm and was highest in the acacia–grass forest. The total litter mass for the acacia–grass forest, 3.49 ± 0.06 t·ha−1, was significantly higher than that for the other forest types. The mass of the undecomposed litter (UL) layer was significantly lower than that of the semi-decomposed litter (SL). (2) The maximum water-retention capacity (Wmax) and effective water-retention capacity (Weff) of the SL layer were greater than those of the UL layer. The Wmax and Weff for the acacia–grass forest were markedly larger than those of the eucalyptus–grass, bamboo–grass, and shrub–grass forests. The water absorption rates of the SL and UL layers were highest during the onset of the immersion experiment, declined exponentially with time, and declined rapidly in the first 2 h. (4) The soil bulk density ranged from 1.46 g·cm−3 to 1.54 g·cm−3, and the total porosity ranged from 32.06% to 37.13%. The soil bulk density increased with the increasing soil depth, while the total porosity decreased gradually. The soil water-holding capacity of the soil layer of 0–60 cm in the acacia–grass forest (301.76 t·ha−1) was greater than that of the other forest types. A comprehensive evaluation of the water conservation capacity by the entropy weight method showed that the water conservation capacity was greatest in the acacia–grass forest. The higher water-holding capacity of the acacia–grass forest may be more effective in enhancing rainfall interception, minimizing splash erosion, and decreasing surface runoff. Here, the results indicate that acacia–grass forest restoration can mitigate soil erosion by favoring soil and water conservation, improving the environment in the gully erosion area of latosol.

Differential Hydrological Properties of Forest Litter Layers in Artificial Afforestation of Eroded Areas of Latosol in China

Litter is one of the key components of the forest ecosystem and plays a role as the second active layer influencing hydrological processes, which has affected the global water cycle. Soil- and water-conservation forests were constructed by artificial afforestation as a part of vegetation restoration in the eroded area of Latosol, and little is known about the differences in the hydrological properties of vegetation restoration in the eroded area of Latosol in the tropical region. We investigated the litter thickness, mass, and hydrological properties in three soil- and water-conservation forests (Eucalyptus robusta, Hevea brasiliensis, and Acacia mangium) through in situ surveys and laboratory experiments. The results showed that (1) the total litter thickness varied from 2.16 to 5.53 cm and was highest in the A. mangium forest. The total litter mass for A. mangium, 14.66 ± 1.09 t·ha−1, was significantly higher than that for E. robusta (5.45 ± 0.59 t·ha−1) and H. brasiliensis (3.01 ± 0.14 t·ha−1). The mass of the semi-decomposed litter (SDL) layer was markedly higher than that of the un-decomposed litter (UDL) layer. (2) The maximum water-retention capacity (Wmax) and effective water-retention capacity (Weff) of the SDL layer were larger than the UDL layer for three forest plantations. The Wmax and Weff for the A. mangium stand were significantly higher than those for the E. robusta and H. brasiliensis stand. (3) The water-absorption rate of the SDL and UDL layer were highest at the onset of the immersion experiment, declined exponentially with time, and especially declined rapidly in the first 2 h. A higher water-holding capacity of A. mangium may be more effective in enhancing rainfall interception, minimizing splash erosion, and decreasing surface runoff. These results indicate that planting A. mangium in E. robusta and H. brasiliensis forests and then turning them into mixed forests should improve soil and water conservation and maximize their ecological benefits.

Germinative and physiological performance of eucalyptus species under abiotic stress

With the increase in cultivated areas, one of the great challenges faced by eucalyptus growers is abiotic stresses, especially because new areas are often affected by water deficit. Therefore, the identification of tolerant genotypes is important to overcome this problem. Thus, the objective of this work was to characterize the germinative and physiological performance of eucalyptus species under abiotic stress. Four Eucalyptus species (E. brassiana, E. camaldulensis, E. saligna, and E. urophylla) were evaluated in two experiments. In the first experiment, the germination potential was assessed under two temperatures (25 and 35 °C) and 11 water potentials of the substrate: 0 (deionized water), -0.05, -0.10, -0.15, -0.20, -0.25, -0.30, -0.40, -0.60, -0.80, and -1.0 MPa. In the second experiment, the species were evaluated in a protected environment under two water regimes comprised by 60% and 20% of the maximum water retention capacity by the soil of the pots. Regarding germination, E. saligna was the most sensitive species to stress, showing only 48% germination on 0 MPa potential (35 °C) and under substrate water deficit it reduced 50% germination on -0.21 MPa (25 °C) and -0.16 MPa potential (35 °C). On the other hand, E. brassiana maintained germination at both temperatures and reduced half of its germination at potentials of -0.33 MPa (25 °C) and -0.32 MPa (35 °C). In protected environment, the physiological metabolism of plants decreased under lower water availability. E. saligna was the species with the highest reduction for the rate of net assimilation and efficiency in water use. In addition, E. camaldulensis showed better physiological performance under water deficit. Thus, E. brassiana and E. camaldulensis would be the most suitable species to be used for breeding program aiming to improve water deficit tolerance. E. saligna is indicated for places with a mild climate and with good water availability. The behavior of the species between the experiments showed that under certain conditions there are correspondences in performance, which indicates that this type of experiment assists in the characterization of species, especially when considering the establishment and initial plant development.

The effectiveness of using hydrated carrot and beet powders inthe production of round cracknels sourdough

Two methods of adding carrot and beet powders to the sourdough of round cracknel products have been studied, such as adding the dry powders and adding the pre-hydrated ones. The water-retaining properties of carrot and beet powders and the change in the lifting force of yeast when applying non-hydrated and hydrated powders before fermentation were investigated. For the experiment, we used Vitbiokor LLC carrot and beet powders. The average integral particle size in carrot powder was 85-95 microns, in beet powder —95-105 microns. We also used the flour of the highest grade Predportovaya(produced by Saint Petersburg Mill Plant, JSC) and the pressed baking yeast produced by Food Combine, JSC. The particle size of the powders was determined by a Malvern Mastersizer 2000 laser diffraction analyzer. The water-holding capacity of the powders was determined by a hydromodule of 1:10 by centrifugation with the rotational speed 6000rpm-1,for 20 minutes (the carrot powder samples) and for 15 minutes (the beet powder samples). The lifting force of the yeast has been determined with the help of the "pop-up ball" method. The powders were hydrated at a hydromodule of 1:5, at a temperature of 30°C for 60 minutes. The results show that carrot powders aged for 40 minutes and beet powders (33%) aged for 40 minutes have the maximum water retention capacity (43%). It was found that the quantity of carrot and beet powders added does not correlate with the lifting force of the yeast in the sourdough samples. It is higher in the samples with the hydrated powders added, rather than in the ones with the non-hydrated powders. Moreover, this difference was more pronounced in the beet powder samples. The study shows the importance of carrot and beet powders hydration before adding them to the sourdough. It’s also significant to conduct the experiments to evaluate the effectiveness of carrot and beet powders hydration before adding them to the round cracknel products sourdough

MUDAS DA PALMEIRA BURITI TEM BAIXA EXIGÊNCIA HÍDRICA EM VASOS COM SOLO

The swamp palm (Mauritia flexuosa L.f.) is a palm tree that occurs in the Brazilian Amazon, Pantanal and Cerrado biomes and occupies wetlands such as the Cerrado swamps. Because of this association and its high size, swamp palm has been used as an indicator of preserved areas. As it is still explored extractively, little has been investigated about its propagation. Seedlings of 90 days developed from seeds in cylindrical tubes (290 cm3) with substrate (composted pine bark) were prepared. An essay was carried out in a completely randomized design with five treatments, 10 repetitions and one seedling per plot (pot). The maximum water retention capacity (MWRC) of a red dystrophic oxisol, with 20% clay, was estimated in a 12-liter pot. The sifted soil was incubated with lime for 30 days with irrigation for 60% of the MWRC and fertilized with N, P, K, S and B. The treatments were flood, 100%, 75%, 50% and 25% of MWRC. The pots were kept in a greenhouse with plastic cover and irrigated daily to replace the water after weighing. Biometric variables were evaluated after four months: stem diameter, shoot length, fresh and dry mass, shoot root ratio, Dickson quality index and water content. Swamp palms irrigated with 25% of MWRC presented the lowest stem diameter, fresh and dry mass, Dickson quality index and water content. The supply of water with 50% of the MWRC allowed swamp palm seedlings to grow as well as those that received more water: 75, 100% of the MWRC or flood. In conclusion, the swamp palm seedlings (M. flexuosa) developed properly with daily irrigations with 50% of MWRC in 12-liter pot with soil.

Biomass pyrolysis with alkaline-earth-metal additive for co-production of bio-oil and biochar-based soil amendment

The alkaline-earth-metal (AEM) has a good performance on modification of both bio-oil and biochar during biomass pyrolysis. In this work, the pyrolysis of rice husk (RH) in the presence of CaO, CaCO3, MgO and MgCO3 was comparatively studied for selecting an appropriate AEM additive to balance the qualities of pyrolytic products. Pyrolysis of RH with the AEM additives could decrease the acids content and increase the hydrocarbons content in bio-oil. Compared with the Ca-additives (i.e., CaO, CaCO3), the Mg-additives (i.e., MgO, MgCO3) were more beneficial for enhancing the hydrocarbons production. The addition of biochar to soil can significantly enhance the water retention. RHC-MgCO3 had a maximum water retention capacity, while RHC-MgO had a minimum water retention capacity due to its lowest specific surface area. Additionally, the Mg-modified biochar had a much higher nutrient (i.e., K+, PO43−) adsorption capacity. In particular, RHC-MgO with a lowest specific surface area had a highest PO43− adsorption capacity, which was evidenced by the adsorption of PO43− onto biochar mainly controlled by the chemisorption process. PO43− adsorbed in the RHC-MgO released rapidly indicating its low PO43− retention capacity. In general, MgCO3 would be an appropriate candidate that is used in pyrolysis of biomass for co-production of bio-oil and biochar composite with high capacities of water/nutrient adsorption and retention for soil amendment.

Volatilization of ammonia from conventional sources of nitrogen and compacted urea under controlled conditions

Urea is the most used nitrogen fertilizer in tropical agriculture, but when applied to the soil surface, it can promote nitrogen (N) losses by volatilization of ammonia (NH3). The present study aimed to evaluate, under controlled laboratory conditions, the N-NH3 losses from conventional N sources and compacted urea . Fertilizers were applied on the surface of a eutrophic Red Latosol of clayey texture (Oxisol), previously moistened to 60% of its maximum water-retention capacity. Conduction of the experiment was in a completely randomized design with six replicates . The treatments were four N sources in doses equivalent to 100 kg ha-1 of N (urea, urea + N-(N-butyl) thiophosphoric triamide (NBPT), ammonium nitrate and urea compacted with additives and polymers), and the additional control groups (soil with no fertilizer and empty chamber). We evaluated the N-NH3 losses by volatilization for a period of 20 days with the aid of hermetically sealed chambers. The results demonstrated the importance of using compacted urea for reducing nitrogen losses via volatilization. These results suggest that choosing the N source can reduce its volatilization and thus improve the harnessing of N from the nitrogen fertilization, when performed with a urea basis.

Screening of Mungbean Genotypes under Polyethylene Glycol (PEG) Induced Drought Stress Condition

Sixteen advance genotypes of mungbeans under 5 different concentrations of Polyethylene Glycol (PEG) were studied to find out the better cultivar against drought stress condition. The experiment results revealed that germination, seedling production and water-related behavior of mungbean genotypes differed significantly under different PEG (drought inducer) concentrations. The mungbean genotype BINA Mung-6 (V8) is proved as highly tolerant against drought stress condition among all other tested genotypes. The results of the investigation revealed that BINA Mung-6 (V8) genotype consistently scored the highest value for all parameters except for the root shoot ratio and water retention capacity that was statistically comparable to genotypes BARI Mung-4 (V2) and BINA Mung-5 (V7). Consistently poor performance were recorded from IPM-02-03 (V16) genotype which is statistically similar as genotypes BMXK1-09015-2 (V13) and BMXK1-09015-6 (V10). The maximum percentage of germination (98.12%), shoot length (139.40 mm), root length (99.07 mm), shoot dry weight (22.32 mg), root dry weight (6.88 mg), relative water content (94.78), water retention capacity (24.98), germination co-efficient (22.27) and vigor index (233.90) were reported from BINA Mung-6 (V8) at a concentration of 0 percent PEG. The minimum percentage of germination (28.22 percent), shoot length (31.17 mm), root length (16.50 mm), shoot dry weight (2.21 mg), root dry weight (0.97 mg), relative water content (25.55), water retention capacity (3.08), germination co-efficient (6.06) and vigor index (13.45) were reported from IPM-02-03 (V16) mungbean advance lines at 0 percent PEG. Maximum (0.92) root shoot ratio was recorded from both BARI Mung-8 (V6) and BMX-08011-2 (V11) mungbean genotypes at 20 percent PEG concentration and minimum (0.22) at 0 percent PEG concentration from BARI Mung-5 (V3) genotype. Maximum water retention capacity (74.45) was recorded at 20 per cent PEG concentration from IPM-02-03 (V16) genotype and minimum (5.22) was at 0 per cent PEG concentration from BINA Mung-6 (V8) genotype.

Evapotranspiration and water sensitivity of Amazonian yellow ipe seedlings under different shading conditions

ABSTRACT The scarcity of information on the agroclimatic and ecophysiological requirements of forest species, especially in the initial phase, limits the production of quality seedlings, the planning and optimization of nurseries. The potential evapotranspiration, crop coefficients (kc) and water sensitivity coefficients (ky) of Amazonian yellow ipe seedlings were determined under different shading conditions and levels of water replacement to the substrate, in the dry period (July to October 2016), in the Cerrado-Amazon Rainforest transition region of the Mato Grosso state, Brazil. The experiment evaluated the full sun and black polyester nets with 35, 50, 65 and 80% shading, and the levels of water replacement to the substrate of 25, 50, 75 and 100% ETc in a split-plot scheme, with irrigation fractions established according to the maximum water retention capacity of the substrate. The water consumption of Amazonian yellow ipe was 239.2, 228.6, 204.1, 185.7 and 136.3 mm for cultivation under full sun and shading levels of 35, 50, 65 and 80%, respectively. The daily means of ETc were 3.37, 3.22, 2.87, 2.61 and 1.92 mm d-1, whereas the kc means were 1.13, 1.15, 1.05, 0.90 and 0.60 for the above-mentioned shading levels. ky values ranged from 0.89 to 1.28, with reduction due to the increase of water replacement and increase for higher shading percentage.

Water Availabilities Associated with Natural Phosphate and Triple Superphosphate in Radish Cultivation

Aims: The objective of this study was to evaluate the development of giant Crimson radish cultivated in a oxisol under phosphate fertilizer sources (natural phosphate, triple superphosphate, natural phosphate + triple superphosphate and control) associated with water availabilities (40, 80 and 120% of the field capacity).
 Study Design: The experimental design was completely randomized, in a 4x3 factorial scheme, with 4 replications (48 units).
 Place and Duration of Study: The research was conducted in a greenhouse belonging to the Federal University of Mato Grosso, in the municipality of Rondonópolis (MT).
 Methodology: The dystrophic Oxisol was used to fill the 1.5 dm3 pots. The irrigation management was in accordance with the methodology of the maximum water retention capacity, by the gravimetric method. Phosphate fertilization was applied before sowing using 265 mg dm-3 phosphorus, varying the source used, triple superphosphate and Bayovar Natural phosphate. After the emergence of the plants, the other nutrients were applied to the soil. The parameters related to vegetative development and after the harvest of radish were evaluated at 20 and 35 days after sowing.
 Results: The parameters fresh mass of the aerial part, dry mass of the tubercle, dry mass of the aerial part, fresh mass of tubercle and length of tubercle had the highest values with the use of triple superphosphate, and for the field capacities of 80 and 120%. The highest harvest index (1.51) was found for the use of Natural phosphate in the field capacity of 120%. The water consumption by the plants was higher with the use of triple superphosphate and field capacity of 120% (6,425.25 L). The efficiency of water use was better with the application of triple Superphosphate and 40% of the field capacity (0.0547 g mL-1).
 Conclusion: There was influence of both water availabilities and phosphate fertilization on the studied parameters. Triple superphosphate associated with 80% of the field capacity allowed the best productivity averages for radish.

Exploitation of Orange Peel for Fungal Solubilization of Rock Phosphate by Solid State Fermentation

Present investigation focused on solubilization of Mussoorie rock phosphate (MRP) and Udaipur rock phosphate (URP) by fermentative production of organic acids from orange peel (Citrus sinensis) by Aspergillus awamori (F18). Adopting solid state fermentation (SSF) technology, fungus could be cultivated successfully on the autoclaved peel–rock phosphate mixture. To optimize the P release from the rock phosphates, the effect of process variables, such as bed load (2.5 and 5.0 g orange peel 100 ml−1 flask), the inoculum concentration (10, 20 and 40 %), the moisture content [57, 75 and 100 % of the maximum water retention capacity (MWRC) of the dried substrate] and incubation period (6–24 days) was investigated. Highest soluble P content of 1393.7 µg g−1 substrate was obtained on 24th days of incubation in bed load of 5.0 g substrate, supplemented with URP at humidification pattern of 75 % MWRC and 20 % inoculum (v/w). The recorded increase in soluble P content was 57 %, compared to its 2.5 g bed load counterpart. Oxalic, citric, succinic and malic acid were detected in fermented extract of both MRP and URP. However, their release was affected by the moisture content. Application of fermented orange peel–rock phosphate mixture in soil–plant system improved the available P and phosphatase activity of wheat grown soil by >45 %, compared to conventional practices. Production of soluble P fertilizer using orange peel in SSF is an economical and environment friendly technology that can find application in possible reduction of chemical P input in soil.

Effectiveness of basin morphometry, remote sensing, and applied geosciences on groundwater recharge potential mapping: a comparative study within a small watershed

A multidisciplinary approach using the integrated field of geosciences (e.g., geomorphology, geotectonics, geophysics, and hydrology) is established to conduct groundwater recharge potential mapping of the Kunur River Basin, India. The relative mean error (RME) calculation of the results of three applied techniques and water table data from twenty-four observation wells in the basin over the 2000–2010 period are presented. Nine subbasins were identified and ranked for the RME calculation, where the observation wells-based ranking was taken as standard order for comparison. A linear model has been developed using six factors (drainage density, surface slope, ruggedness index, lineament density, Bouguer gravity anomaly, and potential maximum water retention capacity) and a grid-wise weighted index. In a separate comparative approach, the sub-basin and grid-wise analyses have been conducted to identify the suitable spatial unit for watershed level hydrological modeling.

Classification of Eucalyptus urograndis hybrids under different water availability based on biometric traits

Aim of study: The eucalyptus grows rapidly and is well suitable to edaphic and bioclimatic conditions in several regions of of the world. The aim of this study was to assess the performance of Eucalyptus urograndis hybrids grown under different water availability conditions.Area of study: The study was performed in south-eastern of BrazilMaterial and Methods: We evaluated five commercial hybrids cultivated in pots with the substrate maintained at 65, 50, 35 and 20% maximum water retention capacity. The evaluation was based on the following characteristics: total height (cm), diameter (mm), number of leaves, leaf area (dm2), and dry weight (g plant-1) of leaf, stem + branches, root, shoot and total and root/shoot ratio.Main results: All the characteristics evaluated were adversely affected by reduced availability of water in the substrate. The hybrids assessed performed differently in terms of biometric characteristics, irrespective of water availability. Water deficit resulted in a greater reduction in the dry weight production compared to number of leaves, diameter and height. Hybrids H2 and H5 have favorable traits for tolerating drought. The hybrid H2 shows a stronger slowdown in growth as soil moisture levels drop, although its growth rate is low, and H5 increases the root/shoot ratio but maintains growth in terms of height, even under drought conditions.Research highlights: The results obtained in our experiment show that productive hybrids sensitive to drought could also perform better under water deficit conditions, maintaining satisfactory growth despite significant drops in these characteristics.Keywords: Eucalyptus urograndis; water deficit; drought tolerance.

Chloride ion as nitrification inhibitor and its biocidal potential in soils

The accumulation of chlorine ion in soils and plants due to the continued use of potassium chloride triggers a series of physiological disorders in plants and microorganisms deserving special attention. This study aimed to evaluate the inhibition potential of chloride ions added to soils as ammonium chloride (AC) and/or KCl in the reaction of soil nitrification. The experiment was conducted under laboratory conditions. The soil was incubated for 21 days at 70% of maximum water retention capacity at 25 °C. The addition of AC, combined with KCl, decreased nitrate concentration in the soil. The increase of Cl content in the soil with the use of AC resulted in an inhibition of soil nitrification. The agricultural potential of using AC as N source was shown in many crops, although, caution regarding excess is recommended, which results in a build-up of salt in the soil and causes injury to the root system and microorganisms.

Citric acid production from orange peel wastes by solid-state fermentation

Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5·103 to 0.7·108 spores/g dry orange peel, the bed loading from 1.0 to 4.8 g of dry orange peel (corresponding to 35-80 % of the total volume), and the moisture content between 50 and 100 % of the maximum water retention capacity (MWRC) of the material. Moreover, additional experiments were done adding methanol or water in different proportions and ways. The optimal conditions for CA production revealed to be an inoculum of 0.5·106 spores/g dry orange peel, a bed loading of 1.0 g of dry orange peel, and a humidification pattern of 70 % MWRC at the beginning of the incubation with posterior addition of 0.12 mL H2O/g dry orange peel (corresponding to 3.3 % of the MWRC) every 12 h starting from 62 h. The addition of methanol was detrimental for the CA production. Under these conditions, the SSF ensured an effective specific production of CA (193 mg CA/g dry orange peel), corresponding to yields of product on total initial and consumed sugars (glucose, fructose and sucrose) of 376 and 383 mg CA/g, respectively. These results, which demonstrate the viability of the CA production by SSF from orange peel without addition of other nutrients, could be of interest to possible, future industrial applications.

Perda de nitrogênio pela Brachiaria decumbens após a antese: relação com a umidade do solo

Com o objetivo de avaliar a perda de N por plantas de Brachiaria decumbens no estádio da pós-antese relacionada com a umidade do solo, realizou-se um experimento em casa-de-vegetação, em delineamento inteiramente casualizado, com três tratamentos e seis repetições. Os tratamentos do estudo constaram da colheita de plantas nos seguintes estádios e condições de umidade do solo: (a) A60: estádio de antese e com umidade do solo mantida a 60% da capacidade máxima de retenção de água; (b) PA60: estádio de pós-antese ou maturidade com umidade do solo mantida a 60% da capacidade máxima de retenção de água; e (c) PA20: pós-antese com umidade estabelecida após a antese de 20% da capacidade máxima de retenção de água do solo. As plantas de Brachiaria decumbens, cultivadas em vasos preenchidos com solo arenoso, foram fertilizadas com sulfato de amônio-15N (800mg vaso-1 de N). As plantas dos tratamentos pós-antese (PA60 e PA20) foram colhidas após 17 dias do início do florescimento. O balanço de N do sulfato de amônio (15N) no sistema solo-planta indicou perdas de N, presumivelmente pela parte aérea das plantas de Brachiaria decumbens, no estádio de pós-antese (tratamento PA60), da ordem de 25% em relação ao de antese (A60). A perda de N na pós-antese avaliada no tratamento com déficit hídrico (PA20) foi reduzida comparativamente ao PA60, sendo da ordem de 11% em relação ao tratamento A60.