Moisture-dependent physical properties of jatropha fruit

The physical properties of fruit are important in designing and fabricating equipment and structures for handling, transporting, processing and storage, and also for assessing quality. The study was conducted to investigate some physical properties of jatropha fruit at various moisture levels. The average length, width, thickness and 1000 mass were 29.31 mm, 22.18 mm, 21.36 mm and 1522.10 g, respectively, at moisture content of 7.97% d.b. The geometric mean diameter increased from 24.03 to 24.70 mm and the sphericity varied between 0.82 and 0.83 as moisture content increased from 7.97% to 23.33% d.b., respectively. In the same moisture range, the bulk and true densities decreased from 278 to 253 and 546 to 435 kg m^?3, respectively, whereas the corresponding porosity also decreased from 49.08% to 41.84%. As the moisture content increased from 7.97% to 23.33% d.b., crushing strength was decreased from 275 to 79 N, whereas the angle of repose and surface areas were found to increase from 36.41° to 41.72° and 1815.73 to 1917.59 mm², respectively. The static coefficient of friction of jatropha fruit increased linearly against the surfaces of three structural materials, namely plywood (47.81%), mild steel (62.88%) and aluminium (34.82%) as the moisture content increased from 7.97% to 23.33% d.b.     

Moisture-dependent physical properties of jatropha seed (Jatropha curcas L.)

The study was conducted to investigate some moisture-dependent physical properties of jatropha seed namely, seed dimension, 1000 seed mass, surface area, sphericity, bulk density, true density, angle of repose and static coefficient of friction against different materials. The physical properties of jatropha seed were evaluated as a function of moisture content in the range of 4.75–19.57% d.w. The average length, width, thickness and 1000 seed mass were 18.65 mm, 11.34 mm, 8.91 mm and 741.1 g, respectively at moisture content of 4.75% d.w. The geometric mean diameter and sphericity increased from 12.32 to 12.89 mm and 0.66 to 0.67 as moisture content increased from 4.75 to 19.57% d.w., respectively. In the same moisture range, densities of the rewetted jatropha seed decreased from 492 to 419 kg m⁻³, true density increased from 679 to 767 kg m⁻³, and the corresponding porosity increased from 27.54 to 45.37%. As the moisture content increased from 4.75 to 19.57% d.w., the angle of repose and surface area were found to increase from 28.15° to 39.95° and 476.78 to 521.99 mm², respectively. The static coefficient of friction of jatropha seed increased linearly against the surfaces of three structural materials, namely plywood (44.12%), mild steel sheet (64.15%) and aluminum (68.63%) as the moisture content increased from 4.75 to 19.57% d.w.     

Physical properties of pellets made from sorghum stalk, corn stover, wheat straw, and big bluestem

Densification of biomass feedstocks, such as pelleting, can increase bulk density, improve storability, reduce transportation costs, and make these materials easier to handle using existing handling and storage equipment for grains. The objectives of this research were to study (1) the physical properties of pellets made from corn stover, sorghum stalk, wheat straw, and big bluestem, (2) the effect of moisture content on bulk density, true density, and durability of the biomass pellets, and (3) the effect of hammer mill screen size and die thickness on bulk density, true density, and durability of the pellets. Biomass pelleting can significantly improve the bulk density from 47 to 60 kg/m³ for biomass grinds to 360 to 500 kg/m³ for biomass pellets. Of the four types of biomass pellets, wheat straw pellets had the highest bulk density value of 495.8 kg/m³, and sorghum stalk pellets had the lowest bulk density value of 365.2 kg/m³. An increase in moisture level resulted in a decrease in bulk density and true density of the pellets. The effect of moisture content on durability of the pellets made from corn stover, wheat straw, and big bluestem showed a similar trend; the maximum durability value was 96.8% at the equilibrium moisture content (EMC) range of 9% (d.b.) to 14% (d.b.) for corn stover and wheat straw, and 9% (d.b.) to 11% (d.b.) for big bluestem. A further increase in EMC value resulted in a decrease in pellet durability. For sorghum stalk pellets, the durability value increased initially with increased EMC and reached a maximum of 89.5% at EMC values between 14% (d.b.) and 16% (d.b.). Use of a larger hammer mill screen size (from 3.2 mm to 6.5 mm screen openings) resulted in increases of bulk density, true density, and durability of biomass pellets, but not in significant levels. Use of a thicker die size (from 31.8 mm to 44.5 mm in thickness) resulted in significant increase of bulk density, true density, and durability of biomass pellets.     

Some physical properties of rough rice (Oryza Sativa L.) grain

Designing the equipment for processing, sorting, sizing and other post-harvesting equipment of agricultural products requires information about their physical properties. In this study, various physical properties of rough rice cultivars were determined at a moisture content of 10% (wet basis). In the case of Sorkheh cultivar, the average thousand grain weight, equivalent diameter, surface area, volume, sphericity, aspect ratio, true density, bulk density and porosity were 21.64 g, 3.35 mm, 31.76 mm², 20.27 mm³, 39.71%, 0.28, 1269.1 kg/m³, 544.34 kg/m³, and 56.98%, respectively. The corresponding values were 20.52 g, 3.4 mm, 32.58 mm², 21.06 mm³, 39.88%, 0.29, 1193.38 kg/m³, 471.21 kg/m³, and 60.37% for Sazandegi cultivar. For Sorkheh cultivar, the average static coefficient of friction varied from 0.2899 on glass to 0.4349 on plywood, while for Sazandegi cultivar the corresponding value varied from 0.2186 to 0.4279 on the same surfaces. Angle of repose values for Sorkheh and Sazandegi cultivars were 37.66° and 35.83°, respectively. Linear model for describing the mass of rough rice grain was investigated. Mass was estimated with single variable of kernel length with a determination coefficient as 0.862 for Sorkheh cultivar whereas for Sazandegi cultivar was as 0.860.     

Moisture-dependent physical properties of niger (Guizotia abyssinica Cass.) seed

Moisture-dependent physical properties of niger (Guizotia abyssinica Cass.) seed were studied at 5.60, 12.99, 19.77, 27.08 and 31.65% moisture content (wet basis). The length, width, thickness and geometric mean diameter increased significantly (p < 0.05) from 3.86 to 4.06 mm, 0.96 to 1.02 mm, 0.86 to 0.96 mm and 1.47 to 1.59 mm, respectively with increase in moisture content from 5.60 to 31.65% whereas the increase in sphericity from 38.10 to 39.01% was not significant. Similarly, thousand seed mass, porosity and angle of repose increased (p < 0.05) linearly from 2.50 to 3.69 g, 41.76 to 47.65% and 29.86° to 39.12°, respectively with increase in moisture content under the experimental condition. The bulk density decreased significantly (p < 0.05) from 635.23 to 561.06 kg m^?3 with increase in the moisture content range considered in the study, whereas the true density showed a slight increase from 1090.71 to 1098.42 kg m^?3 with increase in moisture content from 5.60 to 27.08% followed by a drop from 1098.42 to 1071.75 kg m^?3 as moisture content increased from 27.08 to 31.65%. Coefficient of static friction increased (p < 0.05) logarithmically from 0.34 to 0.51, 0.38 to 0.56 and 0.13 to 0.53 on mild steel, plywood and glass surfaces, respectively with increase in moisture content from 5.60 to 31.65%.     

Measurement and fissuring of rice kernels during quasi-moisture sorption by image analysis

Fissuring associated with kernel elongation was evident in a moisture-adsorbing environment at 15 °C of relative humidity 88.72±0.28% with moisture content from 6% (d.b.) to 16.3% (d.b.). The average length and width of 800 kernels was measured during the sorption test using a Cervitec Grain Inspector equipped with two digital cameras. Samples were exposed to both a moisture-adsorbing and desorbing environments at 15 °C with relative humidities of 23.4±0.53%, 55.9±0.27%, 70.98±0.28% and 88.72±0.28%. On image analysis, the kernels changed in size from 5.13 to 4.84 mm in length and 2.9 to 2.73 mm in width. Both length and width changed as expected during moisture-adsorbing and moisture-desorbing tests. Fissured kernel percent was related to changes in the average length of the kernels during the moisture-adsorbing tests. The average length and fissured kernel percent of rice kernels measured by image analysis may be considered as a reliable indicator of changes in their dimensions during quasi-static moisture sorption processes.     

Evapotranspiration,yield, and water-use efficiency responses of Lesquerella fendleri at different growth stages

Lesquerella fendleri (Gray) Wats. is a potential new oilseed crop for the arid southwestern United States. Lesquerella seed oil with similar properties as castor oil is being considered as a domestic replacement for the imported castor oil. Development of new crops with low irrigation needs is of high priority. Because the most critical stage of sensitivity to moisture deficits has not been determined in Lesquerella species, the objectives of this study were: (i) to identify the most critical stage or stages for moisture deficit and, (ii) to determine the effect of moisture deficit on yield, yield components, oil and fatty acid composition. Two-year field studies were conducted at the New Mexico State University, Leyendecker Plant Science Research Center. The experimental design was a randomized complete block. The treatments consisted of (a) T1: Continuous favorable soil moisture [irrigated at 50% soil water depletion (SWD)]. (b) T2: Moisture stress (75% SWD) from establishment to initial flowering with no stress from flowering to final harvest (50% SWD). (c) T3: No stress imposed from establishment to initial flowering (50% SWD) followed by stress to final harvest (75% SWD). (d) T4: Moisture stress (75% SWD) from establishment to final harvest. The amount of water applied ranged from 810 to 729 mm for the first year, and 810 to 625 mm for the second year. Seed weight per plant and number of pods per plant were generally higher when water availability was maintained at or above 50% SWD throughout the growing season. Neither seed number per pod nor seed size was influenced by irrigation treatments. Lesquerella was more sensitive to water availability during flowering and seed development as a greater loss in seed yield occurred when irrigation was delayed to 75% SWD during that stage of development. Seed yield and dry matter production from the 2 year field studies were closely related to the seasonal cumulative evapotranspiration. For each millimeter of evapotranspiration, seed yield increased from 1.8 kg ha⁻¹ mm in 1994–1995 to 1.3 kg ha⁻¹ mm for 1995–1996. The dry matter production increased 13.4 kg ha⁻¹ for each mm increase in seasonal evapotranspiration during 1994–1995. This relationship was a second order polynomial with an R² of 0.86 during 1995–1996. The WUE_gr and WUE_dm were highest under the most favorable water availability conditions for growth and seed development. Delaying irrigation to 75% SWD throughout the crop growth period resulted in the lowest oil content. Lesquerolic acid content was not affected by irrigation during both the growing seasons.     

Fracture Mechanics of Vitreous and Mealy Wheat Endosperm

The concepts of fracture mechanics have been applied to quantify the fracture behaviour of vitreous and mealy wheat endosperm in a single wheat cultivar. Two new techniques were developed and used to measure fracture toughness (energy per unit area of fracture) of individual grains: (1) load cycling of a notched grain; and (2) instrumented microtome cutting. The load cycling method gave average fracture toughness values for vitreous endosperm of 130 ± 42 J/m² and 50 ± 12 J/m² for mealy endosperm. Fracture toughness measured using the instrumented microtome gave values of 159 ± 7·4 J/m² for vitreous endosperm and 44 ± 4·6 J/m² for mealy endosperm. The results are consistent with the hypothesis that vitreous endosperm has stronger starch-protein matrix bonding than mealy endosperm. The effect of changing grain moisture on cutting fracture properties was investigated. As moisture decreased, values of fracture toughness increased for both mealy and vitreous endosperms at the same rate down to 11% moisture content, below which fracture toughness increased more rapidly for vitreous than for mealy endosperm. Intra-grain fracture toughness was also investigated by cutting successive sections across individual wheat grains. These showed a decrease in cutting force from the outside of the grain towards the centre, and then an increase near the crease. The critical particle size at which a transition from brittle to ductile failure occurs was calculated, giving predicted values of 1·2 mm for vitreous endosperm and 0·9 mm for mealy endosperm at 15% moisture content. This shows that vitreous endosperm undergoes more ductile deformation during deformation than does mealy endosperm, and that larger particle sizes are predicted for vitreous endosperm as a result of milling.     

Predicting maize kernel sink capacity early in development

Development of maize (Zea mays L.) kernels follows a predictable pattern involving rapid increase in dry weight and large changes in water content (WC). We showed previously that final kernel weight (KW) was closely correlated with maximum WC achieved during rapid grain filling. The objectives of the current work were (i) to test if percent moisture content (MC, measured on a fresh weight basis) could be used to normalize genetic and environmental variations in kernel development shown to affect final KW and (ii) to determine whether final KW could be predicted from kernel WC prior to rapid grain filling. The data examined included results from five hybrids varying more than 2-fold in final KW grown in the field, and from previously published results. When KW and WC were expressed relative to their maximum values obtained during kernel development, a single model described the relationship between dry weight accumulation and MC for the larger seeded hybrids (199–352 mg kernel⁻¹) and published results (222–359 mg kernel⁻¹). Two smaller seeded yellow-flint popcorn hybrids, however, accumulated less dry matter per unit moisture than expected. Nonetheless, all genotypes exhibited a common developmental relationship between kernel WC (expressed as a percent of the maximum value) and MC under well-watered conditions. A new model was developed to couple this developmental relationship to final KW. This model accurately predicted final KW from kernel WC values measured prior to rapid grain filling (∼80% MC; root mean square error, RMSE, of 28.9 mg kernel⁻¹) for all hybrids examined and all published results for which KW and kernel WC data were available. The model also provided a simple means to determine whether final KW was limited by photosynthate supply during kernel development.     

Physical properties of chia (Salvia hispanica L.) seeds

Physical properties of Salvia hispanica L. seeds were investigated and their application was also discussed. Physical properties were assessed for white and dark seed separately, except for the angle of repose and static coefficient of friction, which were determined for the seed mixture. The mean moisture content was 7.0% (dry basis). The average for the three characteristic dimensions, length, width and thickness was 2.11, 1.32 and 0.81 mm for dark seeds and 2.15, 1.40 and 0.83 mm for white seeds, respectively. The bulk density, true density and the porosity were between 0.667 and 0.722 g cm⁻³, 0.931 and 1.075 g cm⁻³, and 22.9 and 35.9%, respectively. The equivalent diameter ranged from 1.32 to 1.39 mm. The volume of single grain and sphericity ranged between 1.19 and 1.42 mm³, and 62.2 and 66.0%, respectively. The geometric mean diameter ranged between 1.31 and 1.36 mm for dark and white chia seeds, respectively. This parameter could be used for the theoretical determination of seed volume and sphericity. One thousand seed mass averaged 1.323 g for dark seeds, and 1.301 g for white seed. The angle of repose varied between 16° and 18° whereas the value of static coefficient of friction was 0.28 on galvanized sheet and 0.31 on mild steel sheet.     

Moisture migration in a cereal composite food at high water activity: Effects of initial porosity and fat content

Water sorption isotherms and effective moisture diffusivities were determined at 20 °C for sponge cakes at high water activity as a function of their initial porosity, in the range 86 and 52% (0 g/g dry basis fat content), and of their fat content, ranging between 0 and 0.30 g/g dry basis (67% initial porosity). The equilibrium moisture values were not affected by food structure and decreased with increasing fat content. The effective moisture diffusivity decreased from 7.5 to 0.3×10⁻¹⁰ m²/s with increasing moisture content from 0.30 to 2.20 g/g dry basis. Decreasing initial porosity from 86 to 52% decreased effective moisture diffusivity by more than four orders of magnitude. This behaviour was related to differences of water transfer mechanisms, with the contribution from liquid water diffusion in the solid matrix and from vapour water diffusion in pores. Increasing fat content of 0.30 g/g dry basis in sponge cake, independently of porosity, decreased effective moisture diffusivity by more than five orders of magnitude. A predictive mathematical model was used to simulate moisture intake in two-composite food systems: sponge cakes with varying initial porosities and fat contents and an agar gel as a model of a non-rate limiting water source. Increasing the density of the structure or addition of fat in the cereal-based phase could increase shelf life of composite foods.     

Investigating early vigour in upland rice (Oryza sativa L.): Part I. Seedling growth and grain yield in competition with weeds

This paper is the first of a series that investigates whether new cropping systems with permanent raised beds (PRBs) or Flat land could be successfully used to increase farmers’ incomes from rainfed crops in Lombok in Eastern Indonesia. This paper discusses the rice phase of the cropping system. Low grain yields of dry-seeded rice (Oryza sativa) grown on Flat land on Vertisols in the rainfed region of southern Lombok, Eastern Indonesia, are probably mainly due to (a) erratic rainfall (870–1220 mm/yr), with water often limiting at sensitive growth stages, (b) consistently high temperatures (average maximum = 31 °C), and (c) low solar radiation. Farmers are therefore poor, and labour is hard and costly, as all operations are manual. Two replicated field experiments were run at Wakan (annual rainfall = 868 mm) and Kawo (1215 mm) for 3 years (2001/2002 to 2003/2004) on Vertisols in southern Lombok. Dry-seeded rice was grown in 4 treatments with or without manual tillage on (a) PRBs, 1.2 m wide, 200 mm high, separated by furrows 300 mm wide, 200 mm deep, with no rice sown in the well-graded furrows, and (b) well-graded Flat land. Excess surface water was harvested from each treatment and used for irrigation after the vegetative stage of the rice. All operations were manual. There were no differences between treatments in grain yield of rice (mean grain yield = 681 g/m²) which could be partly explained by total number of tillers/hill and mean panicle length, but not number of productive tillers/hill, plant height or weight of 1000 grains. When the data from both treatments on PRBs and from both treatments on Flat land, each year at each site were analysed, there were also no differences in grain yield of rice (g/m²). When rainfall in the wet season up to harvest was over 1000 mm (Year 2; Wakan, Kawo), or plants were water-stressed during crop establishment (Year 1; Wakan) or during grain-fill (Year 3: Kawo), there were significant differences in grain yield (g/1.5 m²) between treatments; generally the grain yield (g/1.5 m²) on PRBs with or without tillage was less than that on Flat land with or without tillage. However, when the data from both treatments on PRBs and from both treatments on Flat land, each year at each site, were analysed, the greater grain yield of dry-seeded rice on Flat land (mean yield 1 092 g/1.5 m²) than that on PRBs (mean 815 g/1.5 m²) was mainly because there were 25% more plants on Flat land. Overall when the data in the 2 outer rows and the 2 inner rows on PRBs were each combined, there was a higher number of productive tillers in the combined outer rows (mean 20.7 tillers/hill) compared with that in the combined inner rows on each PRB (mean 18.2 tillers/hill). However, there were no differences in grain yield between combined rows (mean 142 g/m row). Hence with a gap of 500 mm (the distance between the outer rows of plants on adjacent raised beds), plants did not compensate in grain yield for missing plants in furrows. This suggests that rice (a) also sown in furrows, or (b) sown in 7 rows with narrower row-spacing, or (c) sown in 6 rows with slightly wider row-spacing, and narrower gap between outer rows on adjacent beds, may further increase grain yield (g/1.5 m²) in this system of PRBs. The growth and the grain yield (y in g/m²) of rainfed rice (with rainfall on-site the only source of water for irrigation) depended mainly on the rainfall (x in mm) in the wet season up to harvest (due either to site or year) with y = 1.1x − 308; r² = 0.54; p < 0.005. However, 280 mm (i.e. 32%) of the rainfall was not directly used to produce grain (i.e. when y = 0 g/m²). Manual tillage did not affect growth and grain yield of rice (g/m²; g/1.5 m²), either on PRB or on Flat land.     

灌溉量对玉米生育后期脱水阶段子粒水分的影响

以玉米品种先玉335、九圣禾2468为试验材料,测定不同灌溉量处理的玉米生理成熟至田间收获期间子粒含水率的变化。结果表明,生育期等量灌溉和分配灌溉量试验,在9.0×10~4株/hm^2、12.0×10~4株/hm^2种植密度下,灌溉量增加使子粒含水量呈增加趋势,且脱水速率减慢。灌溉量从3 600 m^3/hm^2增至7 200 m^3/hm^2,子粒含水率分别增加0.94~2.87个百分点,差异达显著水平。灌溉量与种植密度双因素辅助试验,在种植密度6.0×10~4株/hm^2至13.5×10~4株/hm^2时,灌溉量从3 000 m^3/hm^2增至6 000 m^3/hm^2,子粒含水率分别增加1.60~5.00个百分点;在灌溉量3 000 m^3/hm^2和6 000 m^3/hm^2条件下,种植密度从6.0×10~4株/hm^2增至13.5×10~4株/hm^2,子粒含水率有差异,无明显增加或降低趋势;4 500 m3/hm^2灌溉量下各种植密度处理间的子粒含水率未表现出显著差异。     

Effects of shredding on silage density and fermentation quality

The effects of shredding forages on the density and fermentation quality of the resulting silages were studied. Lucerne (Medicago sativa L.), red clover (Trifolium pratense L.), perennial ryegrass (Lolium perenne L.) and a grass–clover mixture were harvested and wilted indoors for 1–2 days. The dry‐matter content of the forages after wilting was 192 g/kg, 192 g/kg, 237 g/kg and 214 g/kg respectively. The forages were then either unprocessed or shredded once (1×) or four (4×) times using a novel laboratory shredder and were ensiled in laboratory‐scale silos. Fermentation was terminated after either 50 or 113 days of ensiling. Density and the fermentation weight losses of the silages were recorded. Initial density of the silages was considerably increased with increased intensity of shredding (p < 0.01). The initial density (DM basis) of the 4× shredded silages ranged from 177 to 236 kg DM/m³ whereas it was 124–163 kg DM/m³ in non‐shredded silages. The 4× shredded silages had the greatest fermentation weight loss at day 1 of ensiling (p < 0.01). Overall fermentation weight loss after 113 days of ensiling was reduced in the 4× shredded silages (p < 0.01). Shredding increased L‐lactate concentration and reduced pH of the silages (p < 0.01). The NH₃ concentrations were reduced by 25%–46% in 4× shredded silages and butyrate concentrations were reduced by 76%–97% in shredded silages in comparison to non‐shredded silages (p < 0.01). Shredding improved initial density and fermentation quality of silages while reducing overall fermentation weight losses.     

DA型玉米脱水剂的脱水效果及其对玉米营养品质的影响

以龙单25为试验材料,研究DA型玉米脱水剂的应用效果。结果表明,DA型玉米脱水剂可以明显加快玉米子粒的脱水速度,增加产量。处理后28 d,使用脱水剂剂量为900、1 200、1 500、1 800 mL/hm2处理的玉米子粒含水量分别为28.67%、26.36%、22.20%和20.51%,与对照相比,子粒含水量减少10.23～18.39个百分点。低剂量脱水剂对玉米品质无显著影响,可显著增加玉米的穗粒重和产量,平均增产654.3 kg/hm2。     

Effects of clear plastic film mulch on yield of spring wheat

This paper explores the possibility of improving yields of spring wheat (Triticum aestivum) by using plastic film mulching. Field experiments compared three mulching treatments viz. for 20 d (M1), 40 d (M2), and 60 d (M3) after sowing (DAS), with a non-mulch control (CK). Mulching increased temperature and moisture in the upper 5 cm of soil, and shoots emerged 8 d earlier than in CK. Mulching also increased number of tillers, length of the growing period, spikelet and grain numbers per spike, and the duration from flowering to harvest. In the mulched treatments, photosynthesis rate and soluble sugar content were higher in the vegetative period, but soluble sugar content was lower in the grain filling period relative to CK. Grain yield following 20 d mulching was greatest (8207 kg ha⁻¹), and decreased gradually as the mulching period increased (7847 and 6702 kg ha⁻¹ for M2 and M3, respectively). Plastic film removed after 20 d maximizes yield and minimizes soil pollution.     

种植密度对不同熟期玉米品种子粒含水率和产量的影响

2019～2020年以陕单 650(中熟)和东单 60(晚熟)为材料,设置 4个种植密度 6.0×10⁴、 7.5×10⁴、 9.0×10⁴和10.5×10⁴株/hm²,研究密度对玉米产量及子粒含水率的影响。结果表明,增密可以提高不同熟期玉米品种的产量,陕单 650在密度为 9.0×10⁴株/hm²时最优产量为 18 083.5 kg/hm²,东单 60在密度 7.5×10⁴株/hm²时最优产量为17 472.9 kg/hm²。两个品种粒重及子粒含水率随密度的增大而减小,陕单 650达到最大灌浆速率的天数、平均灌浆速率较东单 60均早 4 d和高 0.06 g/d;陕单 650和东单 60子粒平均脱水速率为 0.98%/d和 0.93%/d,陕单 650在生理成熟 4 d后子粒含水率迅速降至 25%。当密度为 9.0×104株/hm²时,陕单 650的叶片干物质转运率明显高于东单 60。通过适度增密提高产量、缩短生育期降低子粒水分的技术途径,协同实现陕西春玉米密植高产机械子粒收获生产。     

Physical properties of tung seed: An industrial oil yielding crop

Data on physical properties of seeds have significant importance for machinery and process equipments design. This study was conducted to investigate some physical properties of tung seed (Aleutites Fordii) namely, dimensions, 100 unit mass, arithmetic mean diameter, geometric mean diameter, sphericity, aspect ratio, surface area, bulk density, true density, porosity, terminal velocity and coefficient of friction. The applications of these properties are also discussed. The tung seed has an average of 13.24% (d.b.) moisture and 40.37% oil content. The average seed length, width, thickness were 22.61 mm, 20.35 mm, 13.95 mm, respectively. The average surface area of tung seed is 1084.20 mm² while the sphericity and aspect ratio were 0.82 and 90.07%, respectively. The average bulk density of seed was 0.502 g/cm³ while the true density was 0.995 g/cm³, and the corresponding porosity was 49.88%. The terminal velocity was 8.3 m/s. The static coefficient of friction on three different contacting materials has been found out and the results showed that the mean value of static coefficient friction was least in case of aluminum sheet while it is highest for plywood.     

Shading effects on canopy and tillering characteristics of continuously stocked palisadegrass in a silvopastoral system in the Amazon biome

In silvopastoral (SP) systems, forage responses depend on the microenvironment in which the plants develop. Our objective was to evaluate canopy and tillering characteristics of shaded 'Marandu' palisadegrass [Brachiaria brizantha (Hochst A Rich) Stapf, syn. Urochloa brizantha] under continuous stocking in a SP system. Treatments were one full sun (FS) and three shaded systems (silvopasture, SP) corresponding to distances from tree groves: 7.5 m north (SP1), and 15 m (SP2) and 7.5 m south (SP3) studied during two rainy seasons (Year 1 and Year 2). The tree in the SP system was Eucalyptus urograndis (hybrid of Eucalyptus grandis W. Hill ex Maiden × Eucalyptus urophylla S. T. Blake). The photosynthetic active radiation was greater in FS (923 μmol m^-2 s^-1), followed by SP2 (811 μmol m^-2 s^-1), SP1 (727 μmol m^-2 s^-1) and SP3 (673 μmol m^-2 s^-1). Forage accumulation in FS was 15% greater than the mean of SP1, SP2 and SP3 (10,663 kg DM/ha). There was no difference in net accumulation of leaf, stem and dead material, averaging 3,302, 3,420 and 4,063 kg DM/ha respectively. Leaf accumulation and accumulation rate were greater in Year 2, and leaf accumulation rate was similar among treatments (19 kg DM ha⁻¹ day⁻¹). Leaf proportion increased 14% from Year 1 to Year 2. Specific leaf area was greater for treatments SP1 and SP3 (193 cm²/g). Tiller population density was similar across treatments in Year 1. Shaded palisadegrass maintains leaf productivity similar to FS under continuous stocking in an SP system.     

Effect of SWD irrigation on photosynthesis and grain yield of rice (Oryza sativa L.)

A study was conducted with the objective to determine the influence of (shallow water depth with wetting and drying) SWD on leaf photosynthesis of rice plants under field conditions. Experiments using SWD and traditional irrigations (TRI) were carried out at three transplanting densities, namely D1 (7.5 plants/m²), D2 (13.5 plants/m²) and D3 (19.5 plants/m²) with or without the addition of organic manure (0 and 15 t/ha). A significant increase in leaf net photosynthetic rate by SWD was observed with portable photosynthesis systems in two independent experiments. At both flowering and 20 DAF stages, photosynthetic rate was increased by 14.8% and 33.2% with D2 compared to control. SWD significantly increased specific leaf weight by 17.0% and 11.8% over the control at flowering and 20 DAF stages, respectively. LAI of D2 under SWD was significantly increased by 57.4% at 20 DAF. In addition, SWD with D2 significantly increased the leaf dry weight (DW) at both growing stages. At all the three densities, SWD increased the leaf N content and the increase was 18.9% at D2 density compared with the conventional control. In SWD irrigation, the leaf net photosynthetic rate was positively correlated with the leaf N content (R² = 0.9413), and the stomatal conductance was also positively correlated with leaf N content (R² = 0.7359). SWD enhanced sink size by increasing both panicle number and spikelet number per panicle. The increase in spikelet number per panicle was more pronounced in the 15 t ha⁻¹ manure treatment than in the zero-manure treatment. Grain yield was also significantly increased by SWD, with an average increase of 10% across all treatments. SWD with D2 had the highest grain yield under the both cultivars with or without 15 t ha⁻¹ manure treatment, which was 14.7% or 13.9% increase for Liangyoupeijiu and 11.3% or 11.2% for Zhongyou 6 over the control, respectively.