Yield and P uptake by wheat as affected by P fertilization and soil moisture regime

The influence of different moisture regimes and the method of phosphate application on the availability and uptake of native and fertilizer P by wheat (Triticum aestivum L.) was studied in a field experiment on sandy loam soil low in available P. Phosphorus application up to 39 kg ha^?1 signficantly increased wheat yield irrespective of the method of application. Wheat yield with drill application of 26 kg P ha^?1 was almost equal to that with broadcast application of 39 kg P ha^?1. A mean increase of 230 kg ha^?1 grains was obtained, when P fertilizer was drilled below seed. The relative efficiencly of placement was found to be 1.4 times that of broadcast method. The increase in IW/PAN-E ratio from 0.6 to 1.0 significantly increased grain yield. Scheduling of irrigation at narrow IW/PAN-E ratio but with fertilizer placed gave almost the same yield as was obtained with irrigation scheduled at IW/PAN-E equal to 1.0 and P fertilizer broadcast. Total P uptake by wheat was greater under wetter moisture regimes. The uptake of applied P decreased with increase in soil moisture regime, while that of soil P tended to increase with frequent irrigation. The uptake of soil P was a linear function of moisture supply and under conditions of this experiment P uptake by wheat beyond a P dressing of 20 kg ha^?1 was limited by soil water.     

Yield and nitrogen uptake by rice as affected by variety,method of planting and new nitrogen fertilizers

A field experiment conducted for two years (1977 and 1978) at the Indian Agricultural Research Institute, New Delhi showed that yield and nitrogen uptake by rice was more in the case of medium duration (135 days) variety Improved Sabarmati than in the case of the short duration (105 days) variety Pusa-33. Highest yield and nitrogen uptake by rice was recorded when it was transplanted and lowest when rice was direct-seeded (drilled in moist soil). Broadcasting sprouted seeds on puddled seed bed gave yield and nitrogen uptake in between transplanting and direct-seeding and provides a reasonably acceptable method of planting. Rice responded well to nitrogen and the economic optimum dose was found to be 160–170 kg N ha^–1. Urea briquettes gave the highest yield and nitrogen uptake by rice and was superior to sulphur-coated urea or neem-cake-coated urea with respect to N-uptake. All these new nitrogen fertilizers were superior to urea and therefore hold considerable promise in rice culture.     

Biomass and nutrient uptake ofAilanthus excelsa as affected by N and P fertilization on an aridisol

A field experiment was conducted on a coarse sand soil having pH 8.8 and organic matter 0.06% in Indian arid region, to study the influence of N and P fertilizers on growth, biomass and nutrient content ofAilanthus excelsa, which is an important fodder species of arid and semi arid regions. Three levels of nitrogen (0, 9 and 18 g N tree^–1 as Urea) and of phosphorus (0, 3 and 6 g P₂O₅ tree^–1 as Single Superphosphate) in factorial combinations were taken in triplicate and the experiment was laid in Randomised Block Design. Application of 9 g N plant^–1 improved tree height by 15 to 25%, collar circumference by 30 to 37% and crown diameter by 18 to 26% in the initial 3 years. Total biomass increase due to 9 g N plant^–1 was 76% and 59%, respectively, after 1 and 2 years of planting. Application of 3 g P₂O₅ tree^–1 increased tree height by 8 to 18% and collar circumference by 17 to 24% during initial three years, and total biomass by 70% at 1 year and 30% at 2 years of age. Combined application of 18 g N and 3 g P₂O₅ tree^–1 (N₁₈P₃) was the best treatment which increased tree height by 49%, 85% and 35% and collar circumference by 56%, 10% and 11% at 1, 2, and 3 years of age, respectively. N₁₈P₃ treatment increased the total biomass by 181% at 1 year and 185% at 2 years of age. N and P applications improved considerably the branching of roots and root length and enhanced root biomass by 2 to 3 folds. N₁₈P₃ treatment increased the nitrogen uptake by 304% (4.02 g tree^–1) at 1 year and 211% (42.56 g tree^–1) at 2 years of age. The P uptake was maximum (290.4 mg tree^–1) due to N₁₈P₃ treatment in 1 year old and 11.37 g tree^–1 due to N₉P₆ treatment in 2 year old plantation.     

Softening temperature of glassy polymers as affected by residual stresses

Heat deflection temperature and Vicat softening point of polystyrene and polymethylmethacrylate with various thermal histories were measured. Surface residual stresses were characterized by liquid crazing. Residual stress profiles across the sample thickness were also measured. It is suggested that the softening behavior of glassy polymers is affected by the state of the residual stresses in addition to the traditionally accepted free volume approach.     

Cotton root growth as affected by P fertilizer placement

Growth chamber studies were conducted to evaluate root growth and P uptake by cotton (Gossypium hirsutum L.) as affected by the proportion of the soil volume that is treated with fertilizer P. Cotton seedlings were grown in a Dewey silty clay loam (Typic Paleudult) and a Marvyn loamy sand (Typic Paleudult). The Dewey soil had a low-P status and the Marvyn soil had a high-P status (7 and 44 mg kg^–1 Mehlich I extractable P, respectively). Phosphorus was added at a constant or base rate which was added to decreasing proportions of the soil volume (i.e. 1.0, 0.5, 0.25 and 0.125). The addition of the same amount of P to decreasing proportions of the soil volume resulted in a stimulation of root growth in the P-fertilized soil volume relative to the nonfertilized soil. The degree of stimulation was similar for the two soils which differed in P status. Phosphorus uptake reached a maximum when 0.25 and 0.50 of the soil volume was treated with P on the Marvyn and Dewey soils, respectively.     

Yield response of lentil to directly applied and residual phosphorus in a Mediterranean environment

The response of lentil grown under rainfed conditions to directly applied and residual phosphorus (P) was described by a modified Mitscherlich equation, accounting for the effects of rainfall on (1) potential yield, and (2) the availability of soil-P to the crop. The response of lentil yield to directly applied and residual P was studied in two-course cereal–lentil rotational trials under rainfed conditions in a Mediterranean-type environment. Cereal crops were grown at different P application rates during 4 growing seasons at 3 sites, representing different rainfall zones in northwest Syria. Lentil (Lens culinaris Med.) was grown during 4 seasons at the same sites, each lentil crop following a cereal crop. In 3 out of 4 lentil-growing seasons, additional P was applied to lentil in subplots to compare the residual and direct effects of P application. The initial contents of extractable soil-P (P-Olsen) were low at all sites, in the range of 2–5 ppm P. Under the conditions of the experiments, lentil appeared to benefit slightly more from P applied to the preceding wheat crop (residual P) than from directly applied P. It is shown that the modified Mitscherlich equation could be used as a basis for P fertilizer recommendations for rainfed farming. As for lentil, it was concluded that a single application of P to the wheat crop in a wheat/lentil rotation could reduce the cost of lentil production, without reducing lentil yield.     

Herbage biomass and uptake under low-input grazing as affected by cattle and sheep excrement patches

Urea deep placement (UDP) has demonstrated its benefits of saving N fertilizer and increasing nitrogen use efficiency (NUE) and grain yields. However, studies on its environmental impacts, particularly on nitrous oxide (N₂O) and nitric oxide (NO), are limited. We conducted multi-location field experiments in Bangladesh to determine the effects of UDP versus broadcast prilled urea (PU) on N₂O and NO emissions, NUE, and rice yields. N₂O and NO emissions were measured from three N fertilizer treatments—no N, UDP, and PU—using automated gas sampling and analysis systems continuously for two rice-growing seasons—Aus (May–August) and Aman (August–December). Fertilizer-induced peaks in N₂O emissions were observed after broadcast application of PU but were rarely observed after UDP. Total seasonal N₂O and NO emissions, yield-scaled emissions, and fertilizer-induced emissions were affected by fertilizer treatments and sites. Though nitrogen fertilizer increased emissions significantly over the control, emissions resulting from UDP and PU were similar. Effects of N placement on grain yields and NUE were site- and season-specific. Of the N placement methods, UDP increased grain yields by 13% (p < 0.05) during the Aman season and gave similar yields in spite of lower N application during the Aus season. UDP increased N recovery from 25 and 16% of broadcast PU to 61 and 73% during the Aus and the Aman seasons, respectively in one site, but was similar in another site. On the other hand, alternate wetting and drying irrigation reduced grain yield and N recovery at the BRRI site during the Aman season.     

Yield and uptake response of lettuce to cadmium as influenced by nitrogen application

A screen house experiment was conducted to determine the effect of N (0, 50, 100 and 150 mg N kg^–1) and Cd (0, 5, 10, 25 and 50 mg Cd kg^–1) on growth and concentration and uptake of N and Cd in lettuce grown for 70 days. Nitrogen application increased significantly fresh yield, dry matter yield, N concentration and uptake, whereas these parameters were significantly decreased by Cd application at all levels of N. The concentration and uptake of Cd were significantly increased by Cd application at all levels of N. This increased Cd uptake was related to increased availability of Cd in soil. Application of N upto 100 mg N kg^–1 increased Cd uptake, whereas there was sharp reduction in Cd uptake at 150 mg N kg^–1 treatment at all levels of Cd. The plant dilution effects and reduced translocation of Cd from roots to tops or the competition at the root absorption sites at highest level of N seem to be the mechanisms responsible for N suppressed Cd uptake in this study.     

Mineral nutrition of wheat,chickpea and lentil as affected by mixed cropping and soil moisture

Interspecific complementary and competitive interactions on yield and N, P, K, Fe, Zn and Mn nutrition of mixed wheat/chickpea and wheat/lentil grown in a glasshouse under normal and drought conditions, and intercropping of wheat/chickpea in the field under rainfed conditions were investigated. The results of the experiments confirmed that drought significantly decreased the growth and mineral nutrition of all plant species. Individual plant dry weights of wheat, chickpea and lentil in the glasshouse experiment, and vegetative shoot dry weight of intercropped wheat in the field experiment were significantly increased by the associated plant species as compared with their monoculture. Even though there were increases in vegetative shoot dry weight of wheat, biological and seed yield of intercropped wheat and chickpea were decreased due to the lower row number in intercropping. However, the calculated LER (Land Equivalent Ratio) was found to be higher than 1.0 for biological and seed yields, showing that intercropping of wheat and chickpea has an advantage over monoculture. In many cases, the drought × cropping system interaction on the nutrient concentrations of plant species was not significant. Results of the glasshouse study showed that P nutrition of wheat was improved by chickpea and lentil, which might result from increases in leaf acid phosphatase in mixed cropping. The release of Fe(III)-complexing compounds from the roots was higher in the sole wheat and mixed culture than that of monocultured chickpea and lentil. This improves Fe nutrition of wheat and chickpea, but those improvements were not significant. However, Zn and Mn concentrations of mixed cropped chickpea were also increased. Under the field conditions, shoot concentration of P, K, Fe, Zn and Mn in wheat were increased by intercropping. Furthermore, the concentrations of Zn and Mn in chickpea were increased by intercropping while N, P and K concentrations were decreased. In addition, the concentrations of N, P, K and Fe for wheat seeds and of Zn and Mn for chickpea were improved by intercropping. It is concluded that interspecific interaction was complementary and generally facilitated the mineral nutrition of wheat and chickpea species grown in mixed culture. Besides giving a yield advantage, intercropping of chickpea and wheat also had a positive effect on seed mineral composition.     

Yield response and iron status of Japanese mint as influenced by soil and foliar applied iron

Japanese mint (Mentha arvensis L.) often suffers from Fe-chlorosis during the regeneration phase after first harvest when grown on alkaline/calcareous soils. Field studies were conducted during 1987 and 1988 seasons on an alkaline sandy loam soil (pH = 8.0; 4.6% CaCO₃) to investigate the influence of soil and foliar applied Fe on yield and Fe status of MAS-1 and Hybrid-77 Japanese mint. Significant oil yield increases were obtained with two applications of Fe-EDTA, and FeSO₄ in mixtures with ammonium sulphate and mint compost (mint distillation waste) and four split applications of FeSO₄ (total Fe of 12 kg ha^–1) between sprouting and 30 days after first harvest compared to the control. The highest oil yields from two harvests (180 kg ha^–1) were consistently obtained with the Fe-EDTA treatment. Soil application of FeSO₄ at sprouting and first harvest were ineffective compared to Fe-EDTA application. Foliar application of 30 kg ha^–1 of Fe-EDTA resulted in oil yields equal to the yields obtained with soil application of 140 kg ha^–1 of Fe-EDTA. Fe applications increased the concentration and the total uptake of Fe by the crop. Foliar application of Fe-EDTA at two weeks interval alleviates Fe-chlorosis in Japanese mint.     

Yield,water use and nitrogen uptake for different water and N levels in winter wheat

In an effort to establish an optimum combination of water and nitrogen for winter wheat a field investigation was carried out on a coarse loamy sand soil during 1984–85 and 1985–86 to assess effects of irrigation regime (IR) and N application on yield, water use and N uptake. The treatments compromised all combinations of three irrigation regimes (IR) based on ratios of irrigation water to cumulative pan evaporation viz.1.2 (I-1), 0.9 (I-2) and 0.6 (I-3) and four rates of N, viz. 0, 60, 120 and 180 kg ha^–1. Grain yield increased with increase in frequency of irrigation. In spite of wide differences in weather during the two years, scheduling of irrigation at IW/CPE = 1.2 gave the highest wheat yield on the coarse-textured soil. During 1984–85, the rainless year, grain yield under I-1 was 20 and 32 per cent higher than I-2 and I-3, respectively. With increasing N rate the yield and water use efficiency increased progressively upto 180 kg N under I-1 and upto 120 kg N ha^–1 under I-2 and I-3 regimes. During 1985–86, the wet year, grain yield response to IR was relatively low. Irrespective of IR, yield increased progressively upto 180 kg N ha^–1 during the wet year. Irrigation water regimes and N application also influenced leaf area index and root growth of wheat. The yield of unfertilized wheat was relatively less affected by seasonal rainfall and IR.Both N uptake and grain yield of wheat were found to increase linearly with increase in water use. Water use efficiency was highest under I-1 regime at all levels of N in the dry season of 1984–85 and under I-3 regime in the wet season of 1985–86. Increase in N uptake with increasing N rates was significantly higher under I-1 than I-2 and I-3 regimes. The N use efficiency being maximum at 60 kg N ha^–1, decreased at higher N levels irrespective of IR.     

Recovery of 15N-labelled fertilizer applied to winter wheat and perennial ryegrass crops and residual 15N recovery by succeeding wheat crops under different crop residue management practices

The recovery of ¹⁵N-labelled fertilizer applied to a winter wheat (120 kg N ha^–1) and also a perennial ryegrass (60 kg N ha^–1) crop grown for seed for 1 year in the Canterbury region of New Zealand in the 1993/94 season was studied in the field. After harvests, ryegrass and wheat residues were subjected to four different residue management practices (i.e. ploughed, rotary hoed, mulched and burned) and three subsequent wheat crops were grown, the first succeeding wheat crop sown in 1994/95 to examine the effects of different crop residue management practices on the residual ¹⁵N recovery by succeeding wheat crops. Total ¹⁵N recoveries by the winter wheat and ryegrass (seed, roots and tops) were 52% and 41%, respectively. Corresponding losses of ¹⁵N from the crop-soil systems represented by un-recovered ¹⁵N in crop and soil were 12% and 35%, respectively. These losses were attributed to leaching and denitrification. The proportions of ¹⁵N retained in the soil (0-400 mm depth) at the time of harvest of winter wheat and ryegrass were 36% and 24%, respectively. Although the soil functioned as a substantial sink for fertilizer N, the recovery of this residual fertilizer by subsequent three winter wheat crops was low (1-5%) and this was not affected by different crop residue management practices.     

Yield and chemical composition of sesame,Sesamum indicum L., as affected by variety and location grown

Summary Observation nurseries including 24 varieties of sesame were grown at 23 locations in 16 states. Data for yield, oil and protein content of the seed, and for iodine value of the oil were obtained from certain locations. Sesame seems reasonably well adapted on the better soils of most of the southern one-half of the United States. Average seed yield for varieties at 14 locations was 506 pounds per acre. Average yield of seed, oil, and protein per acre for seven varieties grown at eight locations was 662, 344, and 163 pounds per acre, respectively. The chemical composition of the seed was found to be well within the acceptable range but was markedly influenced both by the varieties and by the locations where they were grown. The average oil and protein contents on a moisture-free basis were 53.53% and 26.25%, respectively. The average iodine value of the oil was 110.0. Average protein content on the moisture- and oil-free basis was 57.28%. The genetic and environmental influences that affect protein content of the seed also inversely affected the oil content. It was suggested that in sesame protein synthesis is favored over oil synthesis as the nitrogen supply to the seed increases. Contribution of the Division of Tobacco, Medicinal, and Special Crops, Bureau of Plant Industry, Soils, and Agricultural Engineering, and the Southern Regional Research Laboratory, Bureau of Agricultural and Industrial Chemistry, U. S. Department of Agriculture. Agronomist, Division of Tobacco, Medicinal, and Special Crops in cooperation with the Department of Agronomy, Texas Agricultural Experiment Station; and chemist, Southern Regional Research Laboratory, New Orleans, La., respectively. The authors wish to acknowledge the assistance of workers in the various state agricultural experiment stations and government agencies who grew the tests and made data and seed samples available.     

Phosphorus transformations as affected by sampling date, fertilizer rate and phosphorus uptake in a soil under pasture

A phosphorus (P) fertilization study was conducted in the southeast of the Buenos Aires province in Argentina, to determine the effect of P fertilizer rate and sampling date on microbial biomass P, and of organic and inorganic P extractable with 0.5M NaHCO₃, in a soil under pasture. In addition, Bray-P, dry-matter production and P uptake were measured. Soil was sampled at different times over one year, and two to three years after application of 0, 50, 100 and 200 kg P ha ^–1. The addition of P fertilizer significantly increased total soil P and the labile fraction of P extractable with NaHCO₃, with the greatest change in the labile inorganic P form, but had no effect on microbial biomass P. Fractions of P showed different patterns of seasonal variation. Microbial biomass P had a peak in winter and a lowest value in summer, the opposite occurring with NaHCO₃-extractable organic P, while NaHCO₃-extractable inorganic P remained relatively constant throughout the year. The cumulative dry-matter yield after three years was 31% higher in the fertilized than in the unfertilized treatments; the highest being 27660 kg ha^–1 for 200 kg P ha^–1. Concentration of Bray-P increased by 0.18 mg P kg ^–1 for each additional kg P ha^–1 added, but remained relatively constant over the year. A significant correlation was found between available Bray-P and microbial biomass P (r = 0.53), and NaHCO₃-extractable organic P (r = 0.47), suggesting that these organic fractions may contribute to plant nutrition.     

Yield variation of rainfed rice as affected by field water availability and N fertilizer use in central Benin

Rice is mainly grown under rainfed conditions in West Africa. Unpredictable and variable rainfall, poor soil quality, and suboptimal crop management practices are the main determinants of low productivity. We assessed the effects of soil water availability and fertilizer application, and their interaction on the yield of rainfed rice in Glazoué, Department of Zou-Collines, central Benin between 2010 and 2013. On-farm fertilizer management trials and field surveys were conducted in 13–39 farmers’ fields per year. Field water conditions were visually assessed three times per week during the rice-growing season and flood and drought indices were calculated on the basis of number of days with ponded water and dry surface soil relative to the total number of days for the vegetative, the reproductive and whole rice-growing period. Variations in flood and drought indices were related to the sand content of the soil. While nitrogen was the most limiting nutrient, average response to N fertilizer application was low with an agronomic N use efficiency of only 7–9 kg grain per kg of N applied. Year-to-year variation in rainfall and spatial variation in field water status affected both rice yield and response to N fertilizer. Some 47% of the observed yield variation was explained by field water status and the amounts of N fertilizer applied, with rice response to N fertilizer being less when water was limited. We conclude that the prevailing blanket fertilizer recommendations are unlikely to contribute to yield increases in rainfed systems of West Africa. There is a need for field-specific recommendations that consider soil texture and the spatial–temporal dynamics of water availability.     

Profiles of prebiotic fructooligosaccharides,inulin and sugars as well as physicochemical properties of banana and its snacks as affected by ripening stage and applied drying methods

Abstract

Contents of fructooligosaccharides and inulin along with those of selected sugars in fresh banana of different ripening stages were first determined. Banana was then processed into snacks either by hot air drying (HD) or low-pressure superheated steam drying (LPSSD). Selected physicochemical properties of both fresh banana (moisture content, water activity, flesh-to-peel ratio, total soluble solids content, pH, titratable acidity and firmness) and its snacks (microstructure, texture and color) were investigated. Fresh banana of ripening stage 5 exhibited higher fructooligosaccharides, inulin and sugar contents; its snacks also possessed maximum fructooligosaccharides and inulin contents. Drying methods did not have any significant effect on the contents of these prebiotics. Although snacks from banana of ripening stage 5 possessed higher sugar contents, such contents, when snacks are consumed at the recommended amount, are still lower than the recommend daily intake. Stage-5 LPSSD snack exhibited better texture and color than its HD counterpart, so the former has a potential of being a prebiotic-based snack.     

Nanofluidization as affected by vibration and electrostatic fields

In this paper we investigate the behavior of a fluidized bed of silica nanoparticles under the influence of externally applied vibrations and an electrostatic field. We have observed that the application of these fields separately has opposite effects on bed expansion. On one hand, vertical vibrations enhance bed expansion as the vibration intensity is increased up to a critical value. On the other hand, an electrostatic field applied in the horizontal direction, hinders bed expansion. In previous research papers, it has been suggested that the size of nanoparticle agglomerates could be affected either by vibration or by the action of the electric field. Using the modified Richardson-Zaki method to analyze our experimental data we find that vertical vibration tends to decrease the average agglomerate size in agreement with previous research. However, in this work we look further into the physical mechanisms which affect the response of the fluidized bed. Our results suggest that both vibration and the electric field produce a significant perturbation to the flow of agglomerates within the fluidized bed. Vibration transmits a vertical motion to the agglomerates that enhances bed expansion until the vibration velocity becomes of the order of the expected rising velocity of macroscopic bubbles. At this critical point, bubble growth is stimulated by vibration. A horizontal electrostatic field produces a drift of the charged agglomerates toward the walls that gives rise to fluidization heterogeneity and bed collapse. When both fields are simultaneous applied, these opposed effects can be practically compensated.     

Recovery of 15N-ammonium-15N-nitrate in spring wheat as affected by placement geometry of the fertilizer band

The time course of crop ¹⁵N recovery as affected by placement geometry of nitrogen fertilizer was studied in a field experiment. In frames of30 × 40 cm¹⁵N-ammonium-¹⁵N-nitrate was applied in bands parallel to a single row of growing spring wheat. The fertilizer was banded in nine treatments to a depth of 1.5, 5 or 10 cm combined with a distance from the crop row of 1, 5, 10 or 15 cm, or broad spread on the soil surface. The crop recovery of applied ¹⁵N was calculated on each of 9 sampling dates during the elongation phase. A sigmoid growth function was fitted, and the estimated parameters were analysed statistically. The maximum uptake rate was5.5–6kg N ha⁻¹ day⁻¹, and during an almost linear uptake phase of 7 days the crop recovered 68%of the maximum crop ¹⁵N recovery. Neither the maximum uptake rate nor the maximum crop ¹⁵N recovery was significantly affected by the treatments, whereas the start of the linear uptake phase was affected. By fertilizer placement at 5 cm depth the course of ¹⁵N uptake was delayed 0.5 day cm⁻¹ increase in distance from the crop row. Uptake of ammonium nitrate placed on the soil surface or at a depth of 1.5 cm was delayed approximately 3 days compared to banding at 5 cm depth. This delay corresponded to the time until the first precipitation event. Maximum crop ¹⁵N recovery was obtained before anthesis and 20% of the recovered ¹⁵N was lost during the grain-filling period. In conclusion, the uptake rate of applied nitrogen was unaffected by placement geometry. However, the uptake course of applied nitrogen was delayed both by shallow injection and by increased distance between the crop row and the fertilizer band. This revised version was published online in August 2006 with corrections to the Cover Date.