Higher Field Capacity Research Articles

Comparative assessment of newly designed burial type lowland power cultivator for weed control

Weeds are the major reason for the significant yield reduction in rice cultivation worldwide. Power weeders have been introduced to rice cultivation as an alternative solution for the controversial herbicide applications. The aim of this study was to appraise the newly designed burial type lowland power cultivator through a comparative performance assessment including cost economics. Five weeding methods using Cono-weeder (T1), Modified “Asakura” wooden clog (T2), Rotary power weeder (T3), Newly designed lowland power cultivator (T4) and manual weeding (T5 as the control) were evaluated. The T4 showed a significantly high field capacity of 0.04 ha/h, which is 8 times higher than T5, high field efficiency of 88.30% and weeding efficiency of 62.29% which was similar to the performance of T5. Significantly high performance indexes were observed in T2 and T4 (461.65) followed by T1 and T3. Plant damage percentage, maximum tiller number and the yield did not show any significant variation (p>0.05) among weed control methods assessed. Further, the T4 showed a significantly low cost of weeding of 6583 Rs/ha which was 76% of cost reduction of the T5, and moderately high break-even point of 0.88 ha/yr suggesting that it is appropriate for the medium and large scale farmers. Moreover, T4 showed low fuel consumption (0.556 L/h) and power requirement (0.57 kW) representing 48% and 42% respective reductions over the T3. Further, T4 showed the significant lowest weed re-growth rate which is essential for sustainable weed control. Based on the above results, newly designed burial type power cultivator could be recommended for medium and large scale paddy farming, since it showed high performance compared to other methods assessed. Machine performance could be further improved by high speed, light weight design with efficient turning mechanism. Besides, it is suggested to conduct detailed ergonomic evaluation in future investigations.

Focal plant species and soil factors in Mediterranean coastal dunes: An undisclosed liaison?

Understanding the response of plant species to soil factors on coastal sand dunes is critical for effective conservation of coastal habitats in the Mediterranean basin. Our main objectives were to investigate: i) the main soil factors driving species composition in a Mediterranean coastal dune environment; ii) the ecological requirements of focal plant species with respect to single soil factors; iii) whether the focal species of a given macrohabitat (including EU habitats) have similar edaphic needs. We identified 108 plots with three macrohabitats as strata (embryo dunes; mobile dunes; fixed dunes) by random stratified sampling design along the Tyrrhenian coast of central Italy in areas with a high degree of biodiversity and naturalness. Vegetation and soil data were collected in the plots.Canonical Correspondence Analysis (CCA) confirmed that soil had a main role in driving focal dune species composition as found in other Mediterranean areas and indicated that three factors (field capacity, pH and CaCO3) sufficiently explain patterns of plant species. An inverse relation between field capacity, which proves to be the most decisive feature for differences in species ecological requirements between macrohabitats, and pH was observed. Generalized Additive Models (GAMs) showed that: i) the focal species of fixed dunes have a higher probability of occurrence and response curves that overlap at high field capacity and TOC values and at low pH, showing an opposite trend with respect to the species of embryonic and mixed dunes; ii) species of mixed dunes have a probability of occurrence linked to different values of CaCO3, with Ammophila arenaria showing its optimum at high CaCO3 values. Thus our results sustain the hypothesis that dune focal species, diagnostic and characteristic of coastal dune macrohabitats, have different ecological responses with respect to soil factors. Moreover, species within the same habitat can have different ecological responses due to species competition. Data about edaphic requirements of sand dune species and modelling of their ecological responses suggests that focal dune species can be bio-indicators of soil conditions and provide useful indications for conservation, monitoring and restoration of Mediterranean coastal habitats.

Physical quality of Northern Nigeria Savanna Alfisol: Influence of Jatropha curcas L. and other land use systems

AbstractThis study investigated the impact of three adjacent land use systems [land under arable cropping (ARL), cattle grazing fallow (GFL) and Jatropha curcas L. Orchard (JCL)] on selected soil physical quality indicators in a Northern Nigeria Savanna Alfisol. GFL had significantly higher organic carbon content (26.2–32.1% higher) and bulk density (4.5–9.2% higher) than JCL and ARL respectively. Higher bulk density (ρb) in GFL aided by trampling induced compaction resulted in its high relative field capacity (RFC), permanent wilting point (PWP) and micro-pore spaces (PMIC). Continuous tillage in ARL created loose soil in the plough layer (<20 cm) which turn out to its low bulk density (ρb) and high plant-available water capacity (PAWC), total pore spaces (f) and macro-pore spaces (PMAC) over JCL and GFL. Total nitrogen content, dry stability of large macro-aggregate fractions [5–2 mm, (LMag)] and mean weight diameter (MWD) were higher in JCL than GFL and ARL to about 47.2–60.6, 12.5–68.8 and 8.57–44.76%...

Enhancement of physical and hydrological properties of a sandy loam soil via application of different biochar particle sizes during incubation period

In spite of many studies that have been carried out, there is a knowledge-gap as to how different sizes of biochars alter soil properties. Therefore, the main objective of this study was to investigate the effects of different sizes of biochars on soil properties. The biochars were produced at two pyrolysis temperatures (350 and 550°C) from two feedstocks (rice husk and apple wood chips). Produced biochars were prepared at two diameters (1-2 mm and &lt;1 mm) and mixed with soil at a rate of 2% (w/w). Multiple effects of type, temperature and size of biochars were significant, so as the mixture of soil and finer woodchip biochars produced at 550°C had significant effects on all soil properties. Soil aggregation and stabilization of macro-aggregates, values of mean weight diameter and water stable aggregates were improved due to increased soil organic matter as binding agents and microbial biomass. In addition, plant available water capacity, air capacity, S-index, meso-pores and water retention content were significantly increased compared to control. But, saturated hydraulic conductivity (Ks) was reduced due to blockage of pores by biochar particles, reduction of pore throat size and available space for flow and also, high field capacity of biochars. So, application of biochar to soil, especially the finest particles of high-tempered woody biochars, can improve physical and hydrological properties of coarse-textured soils and reduce their water drainage by modification of Ks.

Evaluation of wheat stubble management practices in terms of the fuel consumption and field capacity

Five wheat stubble management practices i.e. chopping the stubble by the chopper mounted on combine during harvest and transmitting the straw to trailer (SCDF), chopping the stubble by the chopper mounted on combine during harvest and spreading the straw to field surface (SCDS), chopping the stubble on field surface after harvest by chopper mounted on combine and transmitting the straw to trailer (SCAF), leaving the stubble on field surface (SLS) and removing the stubble left on field surface by baling (SSB) and the cutting height of combine header (10 and 20 cm) were evaluated in terms of fuel consumption and field capacity. The result of the studies showed that the cutting height of header was increased from 10 to 20 cm, the field capacity increased from 1.195 to 1.365 ha/h and the fuel consumption decreased from 54.472 to 38.859 l/ha. While the highest field capacity was determined in SLS (1.846 ha/h), SCAF and SSB treatments had the lowest field capacity (0.954 and 0.891 ha/h, respectively). Chopping the stubble by chopper mounted on combine and transmitting straw to trailer during harvest increased the fuel consumption of combine by 3.6 times.

Soil Property Changes After Conversion from FOrest to Pasture in Mount Sacinka, Artvin, Turkey

AbstractTurkey's forests have been continuously facing conversion into both agriculture and pasturelands, causing not only degradation and fragmentation of forested lands but also negative changes in soil properties that have not been thoroughly investigated. In order to determine possible changes in some physical and hydrophysical soil parameters along with the dispersion ratio between natural coppice forests and the neighbouring forest‐to‐grassland converted areas, a foothill of Mount Sacinka in Artvin was chosen as a research area. Besides land use, possible effects of elevation change on soil properties due to the mountainous and moderately steep landscape of the region were also taken into consideration. The soil samples were analysed for soil texture, permeability, field capacity, bulk density, organic matter, pH and dispersion ratio. The results indicated that whereas permeability (43·05 mm h−1 in forest and 18·82 mm h−1 in pasture), field capacity (43·45% in forest and 38·08% in pasture) and organic matter (6·36% in forest and 5·34% in pasture) values turned out to be higher in forest soils, bulk density (0·91 g cm−3 in forest and 1·06 g cm−3 in pasture) and pH (5·89 in forest and 6·55 in pasture) values were low in grassland soils, meaning that conversion has negative effects on soil properties. Additionally, the mean dispersion ratios of 27·55% and 33·58% for forest and pastureland soils, respectively, indicated soil erosion problems in both land uses. In addition, as for elevation effect, forest soils especially showed better characteristics at higher elevations with high permeability, field capacity and organic matter and low pH and dispersion ratio. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Effects of agricultural wastes on the hydraulic properties of a loamy sand cropland in Turkey

This study was carried out to determine the proper amount of application for manure (M), hazelnut husk (Corylus avellane L.) (HH), tobacco (Nicotiana tabacum L.) (TO) and tea (Camellia Sinensis (L.)) (TE) wastes based on hydraulic property improvement of a loamy sand cropland in Turkey. The effects of agricultural wastes on field capacity (FC), permanent wilting point (PWP), available water content (AWC), relative saturation (RS) and initial infiltration rate (IR) were determined for a loamy sand soil 7 months after agricultural wastes were incorporated to 15 cm soil depth at four different rates (0, 2%, 4% and 6%, weight:weight) in a randomized plot design experiment with three replicates. While increases in soil OM content for the M application rates were generally lower, TE and HH treatments including high organic carbon (OC) contents resulted in high soil organic matter (OM) increases. Organic wastes generally increased the values of soil hydraulic properties, with increased aggregate stability (AS) and total porosity (F) and reduced bulk density (BD). The highest AS and F values were obtained with 6% HH and 6% TE applications, respectively. Due to different mineralization rates of the organic wastes attributable to their carbon: nitrogen (C:N) ratios, the same application rate had different effects on the soil’s hydraulic properties. Manure, having the lowest C:N ratio, generally had a lower effect on AS and BD. Increased IR due to increases in AS and F by the agricultural waste treatment, especially at 4 and 6% HH, reduced the AW content to 15 cm compared with 2% HH. This indicates that the significant application of higher C:N ratio wastes is not suitable in terms of AW, due to significant improvement of IR. While the highest FC (17.3%) and AWC (10.7%) values were found in the 6% TE application, the highest PWP (7.2%) and IR (333.4 cm h−1) were in the 6% TO and 6% HH applications, respectively. To improve soil physical and hydraulic properties, 6% TO and M, 4% TE and 2% HH applications are suggested for loamy sand cropland.

Sensing Miscanthus Swath Volume for Maximizing Baler Throughput Rate

<abstract> <bold><sc>Abstract.</sc></bold> The cost of harvesting is one of the constraints in improving biofuel economics. Adjusting the ground speed of harvesting machines to maximize their throughput rate in relation to yield level is one of the ways to reduce harvesting cost. To control the ground speed of a baler, a real-time sensor that can predict the swathed-biomass yield in front of the baler would be an invaluable tool. It was hypothesized that the swathed-biomass volume is a reliable predictor of the swathed-biomass yield. A light detection and ranging (LIDAR) based sensing system was developed to sense swathed-biomass volume and was field tested. To correlate the sensed swathed-biomass volume with the Miscanthus yield, a new bale-specific method was developed. A linear correlation (R² = 0.76) was found between Miscanthus yield and sensed swathed-biomass volume at the time of mowing-conditioning. Yield maps were generated using the developed correlation model. The model was also used to predict the harvested plot biomass. The average percent error in predicting the harvested plot biomass was 12.4% for training plots and 10.1% for validation plots. The analysis revealed that a proper control strategy to maximize the baler throughput rate would be to either operate the large square baler at the maximum feasible ground speed (6 km h^-1) or at the maximum achievable throughput rate (35 Mg h^-1). For the specific case analyzed, the proposed control strategy would result in the following advantages: 38.0% higher field capacity, 35.6% higher throughput rate, and 30.4% lower baling cost. Further studies and field evaluation of the proposed control strategy are needed. Studies are also needed to extend the swathed-biomass volume sensing concept to corn stover, other energy grasses, and forage crops.

Sensing Miscanthus Stem Bending Force for Maximizing Throughput Rate in a Disk Mower-Conditioner

Abstract. One of the reasons for relatively high biomass harvesting cost is challenges in adjusting the ground speed of harvesting machines with respect to the yield level within a field. A real-time biomass yield sensor that can predict the yield in front of a machine could be a useful tool to control ground speed. It was hypothesized that the force required to bend Miscanthus stems is a reliable predictor of biomass yield. Based on this novel concept, a stem bending force-sensing system was developed and field tested with a disk mower-conditioner. A bale-specific method, segmenting the field area from which a bale was formed, was developed to correlate sensed bending force and Miscanthus yield. The measured bending force showed a logarithmic relationship (R 2 = 0.80) with Miscanthus yield. The average error in predicting bale-specific yield was 10.3% for training data and 12.9% for validation data. The average error in predicting plot yield was 3.4% for training plots and 10.0% for validation plots. Using the developed logarithmic correlation model, yield maps were also generated. For the specific case analyzed, a proper control strategy to maximize throughput rate (mass per unit time) would be to either operate the mower-conditioner at the maximum feasible ground speed (9 km h -1 ) or at the maximum achievable throughput rate (60 Mg h -1 ). The yield-sensor controlled machine would result in 44.2% higher field capacity, 41.3% higher throughput rate, and 31.2% lower mowing-conditioning cost for the specific case analyzed compared to the operator-controlled machine. Studies are needed to extend the stem bending force-sensing concept to other thick-stemmed crop harvesting machines, such as sugarcane harvesters and coppice harvesters.

Dynamics of soil chemistry in different serpentine habitats from Serbia

To enhance understanding of edaphic conditions in serpentine habitats, a thorough investigation of chemical and mechanical properties of three soils from disjunct ultramafic outcrops in the central Balkans was undertaken. Soil from a nearby chemically-contrasting limestone habitat was also analyzed. Three plant species differently associated with serpentine (Halacsya sendtneri, Cheilanthes marantae, and Seseli rigidum) were references for site and soil selection. Twenty elements were scanned for, and fourteen were measured in seven sequentially-extracted soil fractions. Quantified soil properties also included: pH, levels of free CaCO3, organic matter, P2O5, K2O, N, C, S, cation exchange capacity, total organic carbon, field capacity and soil mechanical composition. The usual harsh components for plant growth in serpentine soil such as elevated Mg:Ca ratio, high levels of Ni, Cr, or Co, were significantly lower in the available fractions. There was a significant positive correlation of organic matter and field capacity, with most available Ca (70-80%) found in the mobile, rather than the organically-bound fraction. This showed that a more favorable Mg:Ca ratio is highly dependent upon a higher field capacity, which is also in accordance with a more developed vegetation. Increasing the availability of metals (Al, Ba, Ca, Cr, Cu, Mg, Ni, Zn) in a more developed serpentine grassland and forest vegetation, occurred only simultaneously with decrease of the Mg:Ca ratio and rise in other factors of fertility (N, P, K). Progressive development of ecosystem complexity therefore raised the availability of metals, but also reduced harsh Mg:Ca ratio disproportion, boosted levels of nutrients and raised soil field capacity. Principal components analysis confirmed that the main differences among serpentine habitats lay primarily in factors of fertility. The common habitat which hosts all three reference species offers intermediate conditions in a plant habitat selection gradient. Comparing serpentine with limestone showed ample difference in total content and availability of most of the surveyed elements, but very few differences in other chemical properties. The fragility of soil and ecosystem, and biological value of serpentine habitats demand intensive research and protection of these diversity and endemism hotspots of the Balkan Peninsula.

Development and Evaluation of Bullocks Drawn Multipurpose Tool Carrier Suitable for the Eastern Plateau

The Multipurpose Tool Carrier (MPT) was developed to prepare the seed bed in dry and wet soil conditions and to perform various other agricultural operations. Various field operations can be performed with the help of the multipurpose tool carrier (MPT) with minimum investments of time and money. The average field capacity of the attachments, that is, cultivator (with shovel and sweep) and seed drill for dry field were found to be 0.1385, 0.1263, and 0.1758 ha/h. It gave higher field capacity (1 ha/day) with additional savings in the cost of operation. The operational cost of MPT cultivator (with shovel and sweep) and seed drill were found to be 551.54, 415.83, and 622.97 Rs /ha respectively in comparison to the Tendua plough. It was observed that the use of MPT is much economical than the traditional methods. The fabrication cost of MPT with attachments (cultivator with shovel, sweep, and seed drill) was about Rs 8000.

Performance of Conventional and Locally Fabricated Chisel Plows in Canefields of the Sudanese Sugar Company

Field performance of a conventional 6-shank chisel plow of a Turkish origin supplied by Giad Company (Sudan) and two chisel plows with 6 and 10 vertical shanks locally fabricated in workshops of the Sudanese Sugar Company (SSC) was studied under conditions of ratoon fields of the SSC. Performance parameters were field capacity, drawbar pull, fuel/ha and energy/ha. Results showed that Giad plow provided higher field capacity (3.6 ha/h), required lowest drawbar pull (7.8 kN), lowest fuel consumption (5.24 L/ha) and lowest energy (7.62 kW-h/ha). Values obtained with the local 6-shank chisel plow expressed as percentages of Giad plow were respectively 96.3%, 119.2%, 126.7% and 121.9%. For the 10-shank local chisel plow, respective values were 93%, 143.6% 136.2% and 146.9%. Resulting furrow surfaces produced by the three plows were practically similar.

Development of High Strength Pancake Coil With Stress Controlling Structure by REBCO Coated Conductor

High strength against electromagnetic force is required for high magnetic field and large capacity coil in order to develop large-capacity superconducting magnetic energy storage (SMES) systems for electric power system control. Also, suppression of delaminating of Yttrium (Y) based coated conductor in a coil is required to manufacture the highly reliable and durable superconducting coil. Insulating coating, using liquid resin of low-temperature-curable-polyamide, was developed and showed durability at very low temperature without deterioration of transport properties of superconducting wire in a coil. Combining paraffin molding, delaminating, and deterioration of transport properties of superconducting wire were not also observed in a coil. These insulating techniques were applied to the pancake coil, in which superconducting wire and the reinforcing outer plates of the coil withstand electromagnetic force. The double pancake coil of this coil structure, called “Yoroi-coil; Y-based oxide superconductor and reinforcing outer integrated coil” was prepared and the durability against electromagnetic force by hoop stress test was verified. The coil achieved 1.5 kA transporting at 4.2 K in 8 T back-up magnetic field without the degradation of transport properties. Maximum hoop stress at the hoop stress test reached 1.7 GPa, based on the calculations. This result confirmed that Yoroi-coil structure has a capability to withstand the large hoop stress, which exceeded the tensile strength of Y-based coated conductors, and bring out highly durable and reliable superconducting coils.

Nitrate leaching from short-hydroperiod floodplain soils

Abstract. Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3−) contamination coming from adjacent agricultural land. Much less is known about nitrogen (N) transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation) and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm) over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation) and N output (leaching) to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the field capacity (FC). In subsoils with high FCs and VWC near FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol L−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3− ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11% to the total nitrate load in groundwater.

Soil physical properties of agricultural systems in a large-scale study

The extent to which findings from small-scale field studies can be used to make agricultural recommendations or management decisions is a concern because of natural influential processes that occur only at a large-scale. A large-scale field study was conducted to determine the effects of agricultural management systems on soil physical properties, including their spatial and temporal variations. Three replicates of the systems were based on soil type in an area that had been intensively mapped and were established in 1998 at the Center for Environmental Farming Systems, Goldsboro, NC. Agricultural management systems include five treatments which were best management practices (BMP: with subplots conventional tillage – BCT and no-tillage – BNT), organic crop production (OCP), integrated crop–animal (ICA), plantation forestry-woodlot (PFW), and abandoned-field succession (AFS). Soil physical properties of bulk density (Db), saturated hydraulic conductivity (Ksat), field capacity (FC), saturated water content (SWC), total porosity (TP), micro- and macroporosity (MicP, MacP), and water stable aggregation (WSA) were measured in multiple years within the period 1999–2007. The experimental methods successfully produced data with acceptable levels of variability, discernable soil property differences between systems, and unambiguous relationships between soil properties. Blocking areas with large portions of a diagnostic soil maintained the homogeneity of experimental plots and produced acceptable error terms in statistical procedures. The sampling scheme used prevented sample collection in previously sampled areas. Tilled systems BCT and OCP did not differ in soil physical properties and their properties remained rather constant with time. The BNT, PFW and AFS systems had similar properties with higher Db, lower TP, higher MicP and higher FC than tilled systems. The ICA sub-treatments developed a post-grazing higher Db, lower TP and lower MacP.

A comparison of soil moisture relations between standing and clearfelled plots with burnt and unburnt harvest residue treatments of a clonal &lt;i&gt;eucalypt&lt;/i&gt; plantation on the Zululand Coastal Plain, South Africa

The effects of clearfelling and subsequent residue retention or burning on water and nutrient balances needs to be understood and quantified on forest sites that are sensitive to loss, so that the long-term sustainable productivity of such sites can be maintained and promoted. An experimental site was established in a clonal eucalypt compartment on the Zululand Coastal Plain, to compare changes in water fluxes through the mature undisturbed eucalypt stand with those after felling and re-planting, under 2 conditions: burning, and retention of the harvesting residues. The study was located in an area of high rainfall and high stand productivity, with sandy soils and low soil carbon and nutrient status; chosen so that the effects of intensive demands on water and nutrient fluxes on a potentially sensitive site could be investigated. This paper presents only the hydrological component of the study. Data collection included weekly determination of rainfall, throughfall, stemflow and soil moisture fluxes from the surface to a depth of 1 m. Drainage rates through the profile were established using time domain reflectometry probes while water drainage volumes were assessed using shallow plate lysimeters. Despite slow growth in the unfelled crop during the monitoring period (attributed to a pest infestation), soil moisture depletion remained rapid and drainage below 1 m remained low. Soil moisture was recharged within a few months after clearfelling, but became rapidly depleted as the canopy of new crop developed and approached canopy closure. A decreased wetting-front velocity and a marginally higher field capacity were proposed as evidence of pore clogging that appeared to occur during the inter-rotation period. The soil profile under the unburnt residue maintained a marginally higher soil moisture status and lower drainage than the soil profile under the burnt residue. Although soil moisture and drainage in the burnt and unburnt residue treatments became similar to the unfelled crop from canopy closure onwards, rainfall additions to soil moisture were depleted faster under the new crop during the first few months after canopy closure. Small differences in soil moisture status between the burnt and unburnt residue treatments presented here may not be sufficient to influence residue manage ment decisions. The length of the inter-rotation period and practice of residue burning may, however, need consideration where soil carbon and nutrient loss or displacement may negatively affect the sustainability of the site.

Environmental Effects on Velvetleaf (Abutilon theophrasti) Epicuticular Wax Deposition and Herbicide Absorption

Controlled environment experiments showed that velvetleaf plants grown under drought stress or low temperature (LT) treatments had greater leaf epicuticular wax (ECW) deposition compared to plants grown in soil with moisture at field capacity (FC) or a high temperature (HT) regime. Light intensity did not affect ECW deposition; however, increasing light intensity decreased the leaf ECW ester content and increased the secondary alcohol content. Plants grown at an LT regime or under FC had leaf ECW with fewer hydrocarbons and more esters than those grown at an HT or drought stress regime. Velvetleaf absorption of acifluorfen increased as light intensity decreased for plants grown in adequate soil water content, while the opposite was true for drought-stressed plants. Velvetleaf absorption of acifluorfen was approximately 3 and 10 times greater, respectively, with the addition of 28% urea ammonium nitrate (UAN) in comparison to crop oil concentrate (COC) or no adjuvant, regardless of the environmental treatments. Plants absorbed more acifluorfen when subjected to the LT regime in comparison to the HT regime when UAN was the adjuvant, while the opposite was true when COC was the adjuvant. Velvetleaf absorption of acifluorfen was not affected by drought stress when COC or no adjuvant was used and varied between studies when UAN was used. Velvetleaf absorption of bentazon was greatest for plants grown under HT/FC or high light/FC treatments and least with plants grown under HT/drought stress or low light/drought stress treatments, regardless of the adjuvant. However, bentazon absorption was higher with the addition of an adjuvant and for plants grown at a high light intensity or FC condition compared with medium to low light intensity or drought stress treatments.

Soil Quality and Tree Growth in Plantations of Forest and Agricultural Origin

Soil organic matter loss and increased soil compaction have been identified as the factors most likely to directly impact tree growth in managed forests. We compared the soil quality of plantations established on former agricultural lands (n = 20) with plantations established following clear cutting of native forests (n = 20). Half of the plantations had been planted with jack pine (Pinus banksiana Lamb.) and half with white spruce [Picea glauca (Moench) Voss], 9 to 27 yr before the study. The old field plantations had lower (at 0–10 and 10–20 cm) mineral soil macroporosity and higher field capacity than forest plantations, indicating more severe soil compaction. The old field plantations, however, also had higher soil C content, raising the permanent wilting point and canceling compaction effects on the available water holding capacity. An indicator of organic matter quality, namely the potential net mineralization per unit of soil Kjeldahl N, was lower in the old fields. Species also affected soil quality indicators—with lower values of macroporosity and higher values of field capacity observed under white spruce. Despite significant differences in soil conditions, no significant effect (P &lt; 0.05) of plantation origin on tree growth could be found. Old fields can support productive plantations of both species.

Soil properties and their effect on water and mineral status of resurrection Ramonda serbica

The resurrection flowering plant Ramonda serbica inhabits the shallow organo-mineral soil that develops in crevices on northern-facing carbonate rocks in the gorges in the Balkan Peninsula. This type of soil represents a complex substrate whose physical and chemical properties were found to be well suited to the most important requirements for the growth and development of R. serbica as well as for the plant’s survival in the state of anhydrobiosis in periods of drought stress. Considerable amount of organic matter (39.4%) in the soil resulted in the high field capacity (134 ml/100 g soil) as well as the slow changes in the amount of its available water. The suitable soil hydric status, based on the organic remains, supports the slow dehydration of this poikilohydric plant, which is extremely important in allowing the activation of the plant’s protective mechanisms. The pH of the soil solution was slighty alkaline (7.7) mostly due to carbonates in its crystallographic structure. The large amount of incompletely decomposed organic debris resulted in a marked difference between total and available nutrient concentration in the soil. Still, the adequate content of nutrients in the leaves points to efficient mineral consumption by the plant roots. The sufficient bioavailability of nutrients and water was also improved by vesicular–arbuscular mycorrhiza detected in R. serbica roots.

Performance Evaluation of Different Spraying Systems in Mango orchard

Three different spraying systems namely, tractor operated aero blast sprayer, power knapsack sprayer and manually operated rocker sprayer were evaluated in laboratory and in a mango orchard to study their performance in terms of size Of droplets and their distribution, penetration capability of spray droplets into the canopy, application rate, field capacity, vertical reach of spray, man-power requirement, fuel consumption and cost of operation. The tractor operated aero blast sprayer was found to produce smallest droplet size (254 µ) with better penetration of spray droplets into the canopy, highest field capacity (1.54 ha/hr) with lowest man-power requirement (1.95 man-hr/ha). The maximum height of reach of the spray of 6.70 m from this sprayer was also sufficient to cover the full height of mango trees. Though the cost of operation of aero blast sprayer (Rs. 197.19/ha) was much higher than that of manual rocker sprayer (Rs. 42.26/ha), the former could be recommended for use in large and small-scale medium height orchards on· individual ownership or custom-hire basis in view of its better performance.