Higher Field Capacity Research Articles

Performance Assessment of the Small and Medium-Scale Coconut Weeder Cum Fertilizer Applicator Developed by Rajarata University of Sri Lanka

The enhancement of coconut yield significantly hinges on proper weeding and chemical fertilizer application. In Sri Lanka, several mechanical methods have been introduced for weeding and fertilizer application of coconut, but the traditional manual approach persists most popular, despite being time, labor cost intensive. Moreover, the introduced technologies were suited for large-scale coconut cultivation and could not cope with medium or small-scale. Furthermore, most of them are designed for a single application; weeding or fertilizing. Thus, the Faculty of Agriculture, Rajarata University of Sri Lanka (RUSL), developed a coconut weeder cum fertilizer applicator for medium and small-scale coconut cultivations. However, it has not been properly evaluated and recommended for farmers. Consequently, this study sought to evaluate the performance of the above machine by conducting a comparative performance evaluation with the conventional method. A healthy, well-maintained, proper-spacing coconut plantation was selected from the faculty research unit, and each weeding and fertilizer application method was replicated ten times. In terms of performance parameters: effective field capacity, field efficiency, and weeding efficiency in mechanical and manual methods were 0.172 ha h-1, 61.86%, 66.62%, and 0.048 ha h-1, 55.34%, 60.35%, respectively. Statistical analysis indicates the mechanical method had higher field capacity and efficiency than the manual method, while weeding efficiency was not significantly different (p≤0.05). In addition, the machine had a fertilizer spreading uniformity of around 99.98% when operating at an optimum speed of 1.45 km h-1. Fertilizer application rate and performance index as a weeder were 1.7 kg/min and 1145.86, respectively. Furthermore, the fuel consumption rate of the machine was 0.733 L h-1 and its break-even point was recorded as 2.85 ha yr-1. Consequently, the coconut weeder cum fertilizer applicator proves suitable for medium and small-scale coconut cultivations in Sri Lanka.

Modelling Soil Moisture Balance for Okra Cultivars in Makurdi Agro Climate Using Decision Support System for Agro Technology Transfer (DSSAT)

Abstract: Soil moisture balance from okra (abelmoschus esculentus) field was performed on experimental plot of the Department of Agricultural and Environmental Engineering, Joseph Sanwuan Tarka University Makurdi -Nigeria. Field and laboratory experiments were conducted on four okra cultivars planted and irrigated by drip system at different levels (80% (I1), 60% (I2), 45% (I3), and 15% (I4)) according to the agronomic practices of okra. Decision Support System for agro technology Transfer (DSSAT) model for the Crop Environment Resource Synthesis (CERES) was used to model soil moisture balance by linear regression (multivariate analysis of variance, (MANOVA)) and validated. The soil was sandy loam with high field capacity (FC) at I4 and nearly uniform drainage (D) except for I4.. Runoff (R) decreases from 35.71 for I1 to 0.07 for I4 implying that R, D and change in water storage (∆S) are functions of the amount and duration of irrigation. The models reported an acceptable deviation from the ideal line of the R and ∆S at higher values confirming degree of the correlation between the observed and predicted dataset but experienced difficulties with estimating lower values due to lower magnitudes in irrigation. From the foregoing it is concluded that decreasing water application results in an increase in irrigation and the reverse is also true.

Development of Dibble Mechanism for Tractor Operated Two Row Semi – Automatic Vegetable Transplanter

Vegetables play a crucial role in daily human nutrition, and India ranks second in vegetable production globally. Despite this, manual transplantation is prevalent in India, characterized by labor-intensive practices. The study aimed to address this by developing a tractor-operated linear dibble mechanism for tomato and chili seedlings, designed with seedling spacings of 45 and 60 cm. The evaluation for optimal operating conditions included varying engine speeds (700, 800, 900, 1000 rpm), gear positions (L1, L2), and power take-off positions (P1, P2). Among these, L1P1 and L1P2, with seedling spacings of 57.57 cm and 45.20 cm respectively, aligned with the designed spacings, while L2P1 was excluded due to excessive dibble spacing. Evaluation concentrated on 800 and 1000 rpm, with 700 rpm causing jerks. The preference for 1000 rpm was driven by higher field capacity, as exceeding 1000 rpm posed difficulties for workers. Selections were made with a focus on achieving desired dibble spacings while taking into account worker comfort and field capacity.

Comparative Performance Analysis of a Remote-Controlled Paddy Weeder in Varied Soil Conditions

Aim: Remote controlled paddy intercultural equipment was evaluated under sandy, sandy loam and loamy soils in terms of fuel consumption (l/h), field capacity (ha/h) and field efficiency (%).
 Study Design: Field evaluation of robotic paddy weeder.
 Place and Duration of Study: Dr NTR College of Agricultural Engineering, Bapatla. Duration of study was from August, 2023 to September, 2023.
 Methodology: The performance evaluation of weeder was conducted at rotary weeder rotational speed of 160rpm and weeding depth of 50mm in terms of the observations on fuel consumption, field capacity and field efficiency. Weeding operation was carried on 20th day and 40th day after transplanting. Each field test was conducted over a run length of 50m at constant speed and depth in different soils were recorded for all the parameters and each test was replicated thrice to eliminate experimental bias.
 Results & Discussion: The highest fuel consumption was observed as 2.2l/h when weeder was operated in loamy soil on 40 days after transplanting and the lowest was 1.2 l/h when the weeder was operated in sandy soils on 20 days after transplanting. The highest field capacity was observed as 0.098ha/h when weeder was operated in sandy soil on 20 days after transplanting and the lowest was 0.076ha/h when the weeder was operated in loamy soils on 40 days after transplanting. The highest field efficiency was observed as 81.66% when weeder was operated in sandy soil on 20 days after transplanting and the lowest was 63.33% when the weeder was operated in loamy soils on 40 days after transplanting.
 Conclusion: The performance of remote operated paddy weeder is best when operated on 20 days after transplanting when compared with 40 days after transplanting for increasing the productivity.

Effects of land-use-cover-changes on selected soil physicochemical properties along slope position, Coka watershed, Southern Ethiopia

Land-use changes along slope position can have a major positive or negative impact on soil environment and agricultural productivity. Relevant information to understand the negative effect of land-use change and slope variability on soil property is a vital element to monitor, plan and make the decision to improve productivity and restore the environment. The aim was to examine the effects of land-use-cover-changes along slope position on the selected soil physicochemical properties in the Coka watershed. Soil samples were gathered from 5 nearby land uses, namely forestland, grassland, bushland, cultivated land, and bare-land, and 3 slope positions (upper, middle, and lower slope) at 0–30 cm soil-depth, analyzed in Hawassa University Soil testing laboratory. The results show that the highest field capacity, available water-holding, porosity, silt, nitrogen, pH-value, cation exchange capacity, sodium, magnesium, and calcium were in forestlands and lower-slope. The highest water-permanent-wilting-point, organic-carbon, soil-organic-matter, and potassium were in bushland; bulk density was in bare land while the highest clay and available-phosphorus were revealed in cultivated land and lower slope. Most soil properties showed a positive correlation with each other except bulk density which has a negative correlation with all soil properties. Generally, cultivated land and bare land have the least concentration in most soil properties which indicates of increasing degradation rate in the area. Thus, soil-organic-matter and other yield-limiting nutrients should be improved in cultivated land to maximize productivity by using an integrated implementation of soil fertility management through cover crops and rotation, compost, manures, and minimum tillage; and amending soil pH-value by liming.

Effect of the Application of Sunflower Biochar and Leafy Trees Biochar on Soil Hydrological Properties of Fallow Soils and under Soybean Cultivation.

Soils enriched with biochar are recommended as a cultivation grounds, especially in case they contain significant amount of sand. However, the interactions between biochar and plants, as well as the influence of the biochar on water retention, cultivation and air properties of soils, are still not obvious. The present study aimed to determine the impact of various biochar doses on soils used for soya cultivation, in comparison to soils maintained as black fallow soil, on their water retention and productivity, for the period of two years. Sunflower husk biochar (BC1) and biochar of leafy trees (BC2), in doses of 0, 40, 60, 80 t·ha-1, were used for field experiments. The water retention was investigated with porous boards in pressure chambers by a drying method. No differences in the hydrological properties of the soils that were differently managed (black fallow soil, crop) were observed following biochar application. Addition of BC1, in the amounts of 40, 60, and 80 t·ha-1, caused an increase in the plant available water capacity (AWC) by 15.3%, 18.7%, and 13.3%, respectively, whereas the field capacity (FC) increased by 7.4%, 9.4%, and 8.6% for soils without biochar. Application of BC2 analogously resulted in higher AWC, by 8.97, 17.2%, and 33.1%, respectively, and higher FC by 3.75, 7.5%, and 18.3%, respectively. Increasing the doses of BC1 and BC2, both on black fallow soils and soils enriched with soya, caused a rise in total porosity (TP) and drainage porosity (DP), and a decrease in soil bulk density (SBD). Biochar with a higher total area and higher porosity (BC1) applied to soils with soya cultivation resulted in lower reductions in AW and FC than BC2 in the second year of investigation.

Effectiveness of Conventional and Minimized Tillage Practices on Soil Quality Properties and Maize Yield Attributes

The effects of tillage systems on soil properties and crop productivity have been the subject of many studies to ensure sustainable productivity. Aims: In the study, the effects of different tillage methods applied in the intermediate period of wheat-maize rotation on the soil quality properties and corn yield elements were investigated in the pre-planting period (PP) and plant growth period (PGP) of corn. Methods: Conventional tillage (CT), minimum tillage with subsoiling and chisel (MT1), minimum tillage with subsoiling (MT2), minimum tillage with chisel (MT3) and direct sowing (DS) methods were compared. As a result of the tillage practices, at 0-20 cm, the highest bulk density values were measured in the DS and CT methods, and 20-40 cm was determined in the CT method. The penetration resistance values of the soils measured at a depth of 0-80 cm were significantly affected by the applications made in both PP and PGP. The highest saturation value was measured in the MT3, the highest field capacity and plant available water contents were measured in the DS. The effects of the applications on the chemical properties of the soil and the nutrient content of the corn plant were limited. The effects on only grain protein ratio from yield components of corn plant were significant, the highest value was measured in CT. Considering the sustainable management of soils labour requirement and lower costs it was concluded that DS and MT methods are more applicable than CT methods in terms of yield.

Anomalous water retention capacity of alpine meadow soil with eolian dust accretion on the Tibetan Plateau

Under high altitude or cold climatic conditions, the characteristics and factors controlling the water retention capacity of alpine meadow soils are poorly known. Here, we focus on alpine meadow soils, with eolian dust accretion, in the Tibetan Plateau and measured basic soil physiochemical properties and soil water retention curves (SWRCs). The results indicate that the competition between eolian processes (dust transport, eolian sorting, and dust accretion) and pedogenesis have led to significant changes of the physicochemical properties and soil water capacity of the alpine meadow soils in both spatial and with depth in the studied area. The most significant features of the alpine meadow soils are the strong accumulation of soil organic matter (SOM), soil acidification, and carbonate leaching. The studied alpine meadow soils have an unusually high saturated water content (SWC), field capacity (FC), and permanent wilting point (PWP). However, the plant available water content (AWC) does not always increase with increasing SOM, because of the rate of increase of the FC does not exceed that of the PWP. We conclude that the negative effects of carbonate leaching on soil aggregate formation and soil structural stability are likely responsible for the observed variations in FC and the resulting AWC. Finally, based on direct measurements of SWRCs and the corresponding alpine meadow soil physicochemical parameters, we developed and validated several pedotransfer functions (PTFs) for these alpine meadow soils which can be used to predict water retention from basic soil data.

Cyanobacteria and moss biocrusts increase evaporation by regulating surface soil moisture and temperature on the northern Loess Plateau, China

Soil evaporation is a three-stage process and plays a vital role in soil physical, chemical, and biological processes, as well as global climate change. As an important living skin, biocrusts strongly influence most soil properties and support fundamental ecosystem functions. Although there are many studies concerning biocrust effects on surface soil hydrological processes, it still remains unclear how biocrusts impact soil evaporation and their potential effects on the water budget in drylands. In this study, we selected aeolian sandy soil (bare soil) and three types of biocrusts, specifically cyanobacteria (cyano), cyanobacteria and moss mixed crusts (cyano-moss), and moss crusts (moss), on the northern Chinese Loess Plateau. By utilizing weighing micro-lysimeters in simulated and ∼4 months in-situ field evaporation experiments, we investigated all evaporation stages containing stages I–II and III, as well as the soil evaporation rate (E) of all treatments. The soil moisture (θ) and temperature (T) at 2 cm and 10 cm depths were also measured in field. Our results showed that biocrust types strongly influenced E in the ranked order of moss > cyano-moss > cyano > bare soil. The cumulative evaporation amount (Ec) of all types of biocrusts was significantly higher than that of bare soil in simulated experiments. Particularly, moss increased Ec by 15.7% compared with bare soil. The results of in-situ field measurements illustrated that the E of cyano, cyano-moss, and moss was increased by 42.4%, 55.5%, and 46.9%, respectively, compared with the bare soil, and these increasing effects became more pronounced after rainfall events. Additionally, all types of biocrusts markedly increased θ and decreased T at 0–10 cm depth of soil, but cyano and cyano-moss increased T (by up to 5.7 °C) at 2 cm depth during the non-rainfall periods. The increasing effects of biocrusts on E were reasonably attributed to their higher contents of fine particles and organic matter, as well as their higher field capacity in contrast to bare soil. All these regulations of biocrusts on soil properties further reshaped soil water and temperature regimes and finally changed soil evaporation. In conclusion, biocrusts may greatly intensify surface soil water loss due to their higher E. However, their greater θ and lower T in comparison to bare soil may partially offset these negative effects in return, and they may have feedback impacts on surface soil water and heat balances in drylands.

Water Infiltration into Sand, Silt, and Clay at Field Capacity

Field capacity (FC), permanent wilting (PWP), and plant available water (PAW) are essential parameters to estimate for soils because they are essential for water irrigation management. However, these parameters were reported in water volume per unit soil volume. Knowing the soil required water volume does not imply immediate water availability, that is, the speed at which the water could be supplied to the soil. This is because there is a lag time between water irrigation initiation and the water increment in the soil depth. This study uses the field capacity’s soil water content to simulate the water infiltration using Richards’ equation. The studied soil medium was silt, sand, and clay. The study allows an estimate of water infiltration time and infiltrated water to relate to the soil depth of interest. The clayey has the highest FC, and the silty soil has the highest PAW. The results revealed silty soil could contain more readily water for plant growth than sand and clay. This study also revealed silty soil to be a better soil medium than sand and clay. It has the best tradeoff between water infiltration time and the infiltrated amount of water for plant absorption. This study’s coupling technique will be a useful tool for farmers and field practitioners to assess any site based on the soil texture at an early stage of water irrigation investigation.

Physical Soil Quality of Semi - Arid Savanna as Influenced by Acacia senegalensis in Desert Research Experimental Plot Yobe State University Damaturu, Northern Nigeria

Soil is a living and dynamic natural reservoir and source of plant nutrients that play numerous key roles in terrestrial ecosystems. This study investigated the impact of three adjacent land use systems (Acacia senegalensis plantation (ACP), pilostigma raticulatum plantation (PRP) and Ground nut field (GNF) on selected soil physical quality indicators in a Northern Nigeria semi- arid Savanna. Minimum data set for assessing soil quality (Prime quality agricultural land) in this study include bulk density, organic carbon content, total nitrogen, carbon stock, available phosphorus and pH values obtained from DRMCC research field. Mean values of the data set were arranged and scored to obtain totals among the minimum data set (MDS). Soil quality is considered a key element for evaluating the sustainability of land management practices. Data generated were analyzed using ANOVA and significant means were determined using Duncan multiple range test (DMRT). ACP had significantly higher organic carbon content (9.37 gkg-1) and lower bulk density (2.16 gkg-1) than pilostigma and GNF respectively. The lower bulk density (ρb) and high organic carbon in ACP might be due to high leaf shading by acacia while the lower bulk density in ground nut field aided by trampling induced compaction resulted in its high relative field capacity (RFC), permanent wilting point (PWP) and micro-p ore spaces (PMIC) tillage in ground nut field created loose soil in the plough layer (<20 cm) which turn out to its low bulk density (ρb). Acacia plantation contained highest total nitrogen value (1.23 gkg-1); perhaps resulting Acacia leaf litter is known to have a high decomposition rate. Pilostigma plantation contained (1.22 gkg-1) nitrogen, while the least nitrogen content was obtained under ground nut field. On scoring the land use types and depth against the minimum data set, the least total was that under acacia plantation, followed by pilostigma plantation then ground nut field. Therefore, soils under acacia plantation were ranked best quality (SQ1) for cultivation purposes at 0-10 cm, followed by pilostigma land use type that were ranked SQ2. Ground nut field soils were ranked least (SQ6) in quality for use in crop production at depth of 10-20 cm.

Effects of land use and reducing conditions of paddy fields on soil quality and high energy moisture characteristic structural stability indices in North of Iran

The present paper is aimed at investigating the effects of land use (particularly reducing conditions of paddy fields) on soil structural stability as characterized by the high energy moisture characteristic (HEMC) method and finding the relationship between soil structural stability and available water (AW) in Amol city in Mazandaran province, Iran. Land use conversion led to a change in the soil organic matter (OM) content. The highest OM was found in the forest and pasture land uses, being significantly different from those of citrus garden and paddy field land uses. The high values of bulk density in the citrus garden and paddy fields can be attributed to intensive machinery traffic and puddling, respectively. However, bulk density was low in pasture and forest land uses because of high OM and macropores. Forest and the paddy fields had higher soil structural stability due to high OM/Clay ratio. The HEMC indices including volume of drainable pores ratio (VDPR) and stability ratio (SR) were calculated using the modified van Genuchten model, and the ratio of slopes at the inflection point of HEMCs of fast-wetted to slow-wetted soil samples (SiR) was determined using the van Genuchten model. The HEMC indices showed positive and significant correlations with OM and OM/Clay ratio. By increasing the OM/Clay ratio, greater clay became complexed with organic matter, and thus soil structure stability increased. A strong correlation was observed between VDPR and OM/Clay in citrus garden and paddy fields. Furthermore, there was a significant correlation between VDPR and AW. The highest field capacity and AW were observed in the forest and paddy fields due to high OM and the presence of smectitic clays under reducing conditions, respectively.

Improvement of the soil properties, nutrients, and carbon stocks in different cereal–legume agroforestry systems

In the present study, the soil properties of the three agroforestry systems including almond intercropped with barley, wheat, and clover rotated yearly with each other were compared at different distances from almond rows with their treeless control systems in the semiarid Saman area, Iran in 2016. Result showed that after eight years, organic carbon contents of the soil were influenced in the agroforestry systems mainly near the trees. Higher soil carbon stocks (56 t/ha) were observed near the almond trees at the distance of 0.5 m. The highest field capacity (28%) and soil organic carbon (1.82%) were also observed at the same distance, especially for the barley. Although there was no significant difference in the nitrogen amount between the systems, the highest amount of phosphorus was observed in the agroforestry plots with barley and clover at 2.5 m far from the trees. Intercropping with almond also increased the available potassium at both distances from the trees. Finally, it can be said that the agroforestry leads to sequestration of higher amounts of carbon in the soil and offers further moisture and more amounts of phosphorus and potassium for the next crop promising a more sustainable agriculture in the next seasons.

Critical Current Under Uniaxial Strain on High-Pressure Heat Treatment Bi-2212 Round Wire

China Fusion Engineering Test Reactor project (CFETR), the next generation of Tokamak, has been incorporated into the important development of nuclear fusion in the future. Compared to the low temperature superconducting materials, Bi-2212 is one of the most promising superconducting materials due to the high irreversible field and outstanding current-carrying capacity. In particular, its critical properties can be improved dramatically by high-pressure heat treatment, which could enlarge its application range. The critical current performance of Bi-2212 round wire (RW) with high-pressure heat treatment under uniaxial strain are studied at 4.2 K in 12 T background field at Institute of Plasma Physics, Chinese Academy of Science (ASIPP). All samples are provided by Northwest Institute for Non-ferrous Metal Research (NIN) in China with new techniques. The results showed that samples with 1 bar pressure heat treatment presented a more drastic degradation under compressive and tensile stress than that the samples heat-treated with 30 and 50 bar pressure. In order to study the influence of different thermal contraction coefficient between the substrate and sample, two springs with different materials were used for the experiment. According to the results, it was found that Cu-Be alloy spring is more compatible for Bi-2212 RW than Ti-6Al-4V alloy spring. In this paper, the experiment setup and results are fully presented.

Assessment of Water Quality and Soil Salinity in the Agricultural Coastal Plain (Ravenna, North Italy)

To improve knowledge on salt leaching suitability on different soils, in Arenosols and Cambisols croplands in the coastal area of Ravenna (Italy), soil samples were collected in the non-irrigation winter period and irrigation summer period. Concurrently, waters of the canal network were also investigated. Soil samples were analyzed for pH, carbonate, total organic carbon (TOC), particle size distribution, electrical conductivity (EC), bulk density (BD) and water content at field capacity (FC). Water samples were investigated for pH, EC, biological and chemical oxygen demand, sodium adsorption ratio, phosphorus, nitrogen, sulfates and chlorides. All soils had low TOC concentrations and Arenosols showed the lowest clay content, BD and FC. Soils had similar EC values in winter, but in summer the lowest ones were observed in Arenosols, suggesting that irrigation mitigated salinization in Arenosols, while the high clay content, BD and FC prevented or limited the salt leaching in Cambisols. In summer, the increase of total nitrogen and biological oxygen demand, especially in drainage channels, might suggest the leaching of soluble nutrients and organic matter from soils due to the high irrigation water volumes. Finally, our findings stress the need to consider soil type and properties to contrast soil salinization without negative effects on soil C leaching caused by salt leaching practice.

Technical and economic evaluation of different operating modes for mechanized fertilizer application in coffee plantations

The present study aimed to investigate the performance parameters and related costs of a machinery set composed of a tractor and a machine for fertilizers and soil correctives application, working in a coffee yard. It was evaluated two different modes of operation. For the first mode of operation (MO1), the machinery applied the total recommended dose to only one side of the plants and traveled in only half of the plot interrows. For the second mode of operation (MO2), the machinery applied half the recommended dose to each side of the plants and traveled in all of the plot interrows. The study was performed at Bom Jardim Farm, located in the municipality of Bom Sucesso, state of Minas Gerais, Brazil. The performance parameters included effective field capacity and effective time. The hourly cost of the fertilizers and soil correctives application operation was determined based on the farm’s management data and the effective cost was obtained by relating the hourly cost and the effective time. The results showed that MO1 implies higher effective field capacity and lower effective cost, with the cost of only 50.1% of that found for MO2. Key words: Agricultural machinery management; costs; Coffea arabica L.

Linkage between machine power utilization and ergonomics, with reference to reducing exertions at work.

Despite mechanization development, leafy vegetable cultivation (LVC), as a labor-intensive activity in both developed and developing countries, still suffers from heavy physical activities. The present study evaluated the human physiological strains of LVC's workers to identify relationships among contributing factors affecting human physiological strains. Thirty male workers were included in this study. Working heart rate (HR) was measured using a heart rate sensor during various operations. The time taken to treat a known area was measured using a stopwatch to calculate work speed (or field capacity (FC)) for each operation. Pearson correlation coefficient and linear regression were used to investigate the relationships among HR, heart rate ratio, FC and mechanization status (MS), and human energy expenditure rate and total energy expenditure per unit area. The highest HR was at seedbed preparing (120.1 beats/min) and lowest at manual harvesting (87.8 beats/min). Manual hoe-used operations (seedbed preparing, manure application and irrigating) were demonstrated as the critical operations concerning physiological strains. The operations performed by machine power corresponded to a high FC. Variables influencing the area treating speed (i.e. MS and FC) are negatively linked to the human energy consumed per unit area and variable changed in time unit (i.e. HR) was positively linked to the human energy expenditure speed.

Plant functional assembly is mediated by rainfall and soil conditions in a seasonally dry tropical forest

Understanding how species assembly is influenced by the interplay of climate, local environmental conditions and human-caused disturbances remains a central question in ecology and conservation. Here, we assess how plant species abundance is determined by combinations of functional traits (ecological strategies) and interacting gradients of rainfall, soil conditions (fertility and field capacity) and chronic anthropogenic disturbance in a Caatinga dry tropical forest, Brazil. We tested for trait–environment relationships using multivariate methods (RLQ) accounting for groups of species sharing similar responses to gradients and similar expression of multiple traits (i.e. response groups). Overall, species’ abundances changed predictably in response to rainfall and soil fertility, and were mediated by functional traits, i.e. species with particular trait combinations tended to respond similarly to multifactorial conditions. Briefly, three ecological strategies emerged: species with low wood density and soft (i.e. lower dry matter content), thick leaves converged into a trait syndrome characterizing a drought-avoidance strategy through water storage. They were particularly abundant under extremely low precipitation and relatively high soil field capacity. Under conditions of increasing rainfall and decreasing soil field capacity, species with high wood density were favored, consistent with a drought-tolerance strategy. However, these species fell into two groups relative to leaf-investment: more conservative leaves (low SLA) on relatively fertile soils vs. thinner and softer (i.e. high SLA) leaves on unfertile soils. In seasonally dry tropical forests, low SLA on relatively fertile soils may represent a water conservation strategy. Unexpectedly, no ecological strategy emerged in response to disturbance. The patterns we uncovered help to understand the interplay between precipitation, soil fertility and anthropogenic disturbance in plant species filtering in seasonally dry tropical forests. Moreover, our results underline that impacts of future climate change will depend on how rainfall patterns covary with finer-scale environmental factors such as soil fertility and field capacity.

Determination of field capacity for the sugarcane harvester using GNSS data

Harvesting is an important activity in the sugar production industry. Due to the labor shortage and time limitation during harvesting season, farmers have adopted cane harvesters to substitute the farm workers in this restless period. Cane harvesters are huge and expensive machines with high field capacity. Because of inappropriate working conditions in Thailand, the actual field capacity is much lower than that in its specification. The objective of this research is to study the factors affecting the field capacity of the sugarcane harvester. A GNSS logging system was used to record the machine’s position and traveling speed during operation. Crop yield for each field was also collected. Field dimension and other working parameters such as working time and the number of turns were derived from the GNSS data. A field capacity prediction model was developed. The study shows that the optimal working speed, crop yield, and the number of turns per field area were significant factors to predict the harvester’s field capacity. The coefficient of determination (R2 value) of the model was 0.625. It was suggested to include more machine and field variation for further robust model development and uses in the optimization of field operation performance.

The Effect of Some Primary Tillage Equipment on Performance Efficiency Under Two Level of Soil Moisture Content and Different Machinery Unit Speeds

A field experiment was conducted in the experiment fields of the college of agriculture - University of Baghdad – Abu Ghraib , 2016 in a silt clay loam soil , to Evaluate the effect of some primary tillage equipment and two of levels of soil moisture content in some of performance efficiency indicator for different forward speed , ArmaTrac 845e and ITM 285 New tractor with moldboard and chisel and sweep plow as a machinery unit have been used in this study .
 Two levels of soil Moisture content include (18 – 20 % ) and (14 – 16%) represented main plot , three types of plow ( moldboard , chisel and sweep) represent sub plot , five machinery speeds included ( 1.5 , 2.53 , 3.75 , 5.3 and 6.71 km.hr-1 ) represent sub plot , Slippage percentage (%) , fuel consumption (L.hr-1) , drawbar pull (KN) , Field capacity (he.hr-1) are have beenbeen measured in this study . And the results have been analyzed by using the order of the spilt - spilt - plot with randomize complete block design with three replicates and tested by the way averages less significant difference and the level of probability of 0.05 .
 The results show that : the soil moisture content ( 14 – 16 % ) has got a less value of slippage percentage % , fuel consumption L.hr-1 , drawbar pull Kn and higher field capacity ha.hr-1 , and sweep plow has got a less value of slippage percentage , fuel consumption and drawbar pull , and the chisel plow has got a higher field capacity , and when the tractor speed is increased it leads to aincrease in the slippage and fuel consumption and drawbar pull and field capacity will be anincrease .