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21.
ABSTRACT

Organic amendments in the soil perform better than synthetic fertilizers in regards to soil fertility and sustainable crop productivity. Experiments were conducted to compare the effects of organic and synthetic fertilizers on soil fertility and wheat (Triticum aestivum L.) productivity. Soil fertility and protein contents of wheat grains (13.2% and 13.3% during 2005–06 and 2006–07, respectively) were improved by organic amendments. However, synthetic fertilizer (at the rate of 150, 100, and 60 kg ha?1 N, P2O5, and K2O, respectively) applications resulted in the maximum grain yield (4.05 and 4.46 t ha?1 during 2005–06 and 2006–07, respectively). The observed and simulated soil organic carbon (SOC) reasonably agreed during RothC model validation (R 2 = 0.99). Economic analysis showed the maximum net profit and relative increase in income ($729 US ha?1 and 309%, respectively) from inorganic treatment. Application of synthetic fertilizers increased grain yield and farm profit while organic manure enhanced grain quality. The RothC model had potential for determining the SOC in organic farming under arid environment.  相似文献   
22.
A field survey was conducted for the sampling of Acetyl-CoA carboxylase (ACCase) inhibitor resistance littleseed canarygrass, a major weed of wheat, from Punjab, Pakistan in 2014 for confirmation of resistance. The surveyed regions encompassed four different cropping systems including rice–wheat, maize–wheat, cotton–wheat and mixed cropping. Dose–response assay was conducted for confirmation of resistance. Efficacy of herbicide mixtures including clodinafop–propargyl, metribuzin, pinoxaden and sulfosulfuron at a range of doses was investigated to manage littleseed canarygrass. Results revealed that all populations were resistant to fenoxaprop except PM-BWL-2. The higher level resistance (6.5) was found in populations collected from rice–wheat cropping system. The tested herbicide mixtures at 75% and 100% of the recommended dose of each mixture component provided the effective control of resistant littleseed canarygrass. Mixtures at 50% provided more than 80% control and reduced growth and seed production potential of surviving plants. The confirmation of ACCase inhibitor resistance as the first case of herbicide resistance in Pakistan, leads us to discourage use of ACCase inhibitor herbicides alone. However, herbicide mixtures at 75% and 100% of the recommended dose are suggested to manage this weed for sustainable wheat production in the surveyed cropping systems.  相似文献   
23.
Endozoochory has been recognised as the most important dispersal mechanism in invasive Prosopis species, because their sugary, tasty pods attract animals and because some of their seeds remain intact after passing through some animals' digestive systems. In this study, we evaluated the role of the camel (Camelus dromedarius) as a potential disperser of the seeds of invasive tree Prosopis juliflora. Four camels of similar weight (ca. 400 kg) and age (ca. 2 years) were each fed with 70 fruits (1000 seeds approximately) of P. juliflora, which were retrieved from the camels' dung at 24‐h intervals for 4 days. The seeds retrieved were tested for germination and viability, along with seeds not eaten by the camels, with and without pericarp. Less than 3% of the seeds eaten were retrieved from the camels' dung. Most of the seeds (74%) were retrieved between 24 and 72 h after ingestion. The passage through the camel gut significantly accelerated and increased seed germination of P. juliflora in comparison with uneaten seeds covered with pericarp (48–75% and 15% respectively). While gut passage liberated P. juliflora seeds from the pericarp, increasing and accelerating their germination, the viability of seeds which had not germinated after germination trials were decreased (ca. ~20%) relative to uneaten seeds that had also not germinated. Our results show that, despite the low recorded seed recovery, camels can potentially disperse seeds of P. juliflora, which is in line with field observation showing P. juliflora expansion along the camels' routes in Gebel Elba National Park, south‐east Egypt.  相似文献   
24.
Excessive soil compaction has negative effects for agriculture and the environment. Measurement of soil strength is a common indirect measure of soil compactness. In the context of precision farming, on-the-go soil mechanical resistance measurements using single- and multiple-tip horizontal sensors have been developed. It has been reported that there was a significant relationship between soil mechanical resistance values measured with both vertically operated cone penetrometer and horizontally operated sensors only for relatively deep layers. It was hypothesized that the differences in horizontally measured soil resistance in different soil layers could be explained by different failure modes. The objective of this research was to develop a horizontal soil mechanical resistance sensor and to observe the failure mode in front of it while penetrating soil at three different depths. A single-tip horizontal penetrometer was equipped with a 30° prismatic tip and had a base area of 324 mm2. The prismatic tip was mounted horizontally to an S-shaped load cell housed inside a shank. A data-logging system was also developed to record measurements with 10 Hz sampling rate. The sensor was tested in a field with silty clay loam soil at three depths of 20, 25 and 30 cm. Cone index (CI) values were obtained with 1 cm depth increments and 1 m horizontal intervals along each transect for comparison using a standard cone penetrometer. The results showed that average horizontal soil mechanical resistance index (HRI) values for both depths of 20 and 25 cm were similar due to the brittle failure mode in both cases. However, when the tip was operated below the critical depth of the sensor, the value of HRI at 30 cm depth increased three times when compared with 20 or 25 cm depth values. This was due to change in failure mode from brittle to compressive mode below the critical depth. There was a significant relationship (R2 = 0.75) between HRI and CI for the 30-cm depth, whereas for shallower depths the relation was not significant. It can be concluded that the correlation between measurements obtained with the vertically and horizontally operated penetrometers would be significant as long as both produced the same soil failure mode.  相似文献   
25.
A field experiment was conducted to evaluate effect of biochar-amended urea on nitrogen economy of soil for improving the growth and yield of wheat under field condition. Experiment plan was comprised of twelve treatments with four replications including treatments without application of urea and biochar (control) and urea only. Biochar was applied at 1–10% of the weight of urea fertilizer applied each treatment. Results showed that application of biochar at 10% with recommended dose of urea significantly improved plant height, spike length, number of tillers, number of spikelet per spike, 1000 grain weight, grain yields, biomass yield, harvesting index, nitrogen (N) concentration and uptake in grain and straw, and agronomic efficiency of nitrogen by 6.0%, 11.1%, 32.0%, 55.3%, 5.4%, 38.0%, 19.0%, 9.0%, 19.0%, 26.0%, 65.0%, 50.0%, and 63.0%, respectively, as compared to treatment comprised of recommended rate of nitrogen without biochar.  相似文献   
26.
The feasibility of Raman spectroscopy in combination with partial least-squares (PLS) regression for the determination of individual or grouped trans-monounsaturated fatty acids (trans-MUFA) and conjugated linoleic acids (CLA) in milk fat is demonstrated using spectra obtained at two temperature conditions: room temperature and after freezing at -80 °C. The PLS results displayed capability for direct semiroutine quantification of several individual CLA (cis-9,trans-11 and trans-10,cis-12 C18:2) and trans-MUFA (trans-4-15 C18:1) in minor concentrations (below 1.0 g/100 g of milk fat). Calibration models were based on reference data cross-correlation or determined by specific scattering signals in the Raman spectra. Distinct bands for trans-MUFA (1674 cm(-1)) and CLA (1653 cm(-1)) from the trans isolated and cis,trans conjugated C ═ C bonds were identified, as well as original evidence for the temperature effect (new bands, peak shifts, and higher intensities) on the Raman spectra of fatty acid methyl ester and triacylglyceride standards, are supplied.  相似文献   
27.
Cadmium (Cd) is a nonessential and toxic element because it inhibits the growth and development of plants and is dangerous for end consumer. It enters in the human food chain through food crops. Application of plant nutrients such as zinc (Zn) and gypsum is a viable and cheap strategy to minimize its accumulation in edible plant portions. Therefore, this investigation was conducted to determine the effectiveness of Zn and gypsum against Cd accumulation in wheat. The results showed that Cd toxicity considerably decreased the plant growth, physiological activities, and yield attributes and increased the Cd accumulation in root, shoot, and grain, while application of Zn and gypsum remarkably increased the growth and yield and decreased the Cd accumulation in plant parts in Cd-contaminated soil. The results also depicted that application of Zn showed better results as compared to gypsum. In conclusion, we can say that application of Zn and gypsum remarkably ameliorated the Cd toxicity and decreased its accumulation in wheat, grown in Cd-contaminated soil.  相似文献   
28.
This research was conducted to explore genetic material that can yield better under salt stress conditions. The experiment was laid out using 27 upland cotton genotypes in a RCBD 2 factorial arrangement with two replications. Saline water (NaCl at 20 dS/m) was applied after satisfactory emergence was achieved. The crop was raised to maturity and data relating to yield, fiber quality and ionic traits were recorded. Analysis of variance showed significant variations in the germplasm. Plant height, bolls per plant, boll weight, GOT%, staple length, staple strength, K+ and K+/Na+ ratio under salinity stress showed a highly significant correlation with seed-cotton yield. The highest direct effect on seedcotton yield per plant was exhibited by bolls per plant and boll weight. The results from the correlation and path coefficient analyses revealed that although the K+/Na+ ratio had a strong positively significant association with seedcotton yield, its direct effect on the seed-cotton yield was negative and thus selection on the basis of K+/Na+ may not be fruitful. Hence, only indirect selection through bolls per plant and boll weight may be effective in increasing the seedcotton yield per plant under salinity stress.  相似文献   
29.
This study was carried out to assess the ability of using pawpaw (Carica papaya) seeds as a natural reproduction inhibitor for tilapia fish (Oreochromis niloticus) culture to control its breeding. Biochemical, physiological and histopathological effects ofpawpaw seeds on male tilapia fish were also determined. Mature male tilapia were stocked for 4 weeks and treated with low dose (3 g/kg/day) and high dose (6 g/kg/day) of ground dried pawpaw seeds mixed with their feed. The obtained results showed that the pawpaw seeds induced permanent sterility in the high dose treated fish while the low dose treatment showed reversible results. The results also demonstrated that fish treated with high dose of pawpaw exhibited higher biochemical and physiological effects as: low meat quality, a progressive fall in erythrocyte (RBCs) count, hemoglobin (Hb) content and haematocrit values. Also the high dose revealed a significant increase in the leukocytes (WBCs) count, serum glucose, total protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine and uric acid levels. Moreover, serum total lipids revealed a significant decrease compared to control group. On the other hand, the low dose treatment revealed lower biochemical and physiological changes. Histological sections of testis showed disintegration of sperm cells and focal necrosis of seminefrous tubules in the high dose treated fish, hepato-pancreas and posterior kidney tissues also showed severe changes in high dose treated fish. Milder degenerative changes in some necrotic foci and slight changes in hepato-pancreas and posterior kidney were observed in the low dose treated fish. The study concluded that pawpaw seeds which are cheap and easy to obtain, can be incorporated into fish feeds with adjusted amount and be used to control breeding of tilapia fish in growing ponds instead of unfavorable and expensive hormonal use.  相似文献   
30.
Effect of dietary tryptophan (TRP) on copper toxicity was investigated in common carp, Cyprinus carpio. Fish were randomly distributed into two triplicate treatments (control and TRP) and fed control (TRP?=?3.1?g?kg(-1)) or TRP (TRP?=?8.1?g?kg(-1)) diets over a 2-week period. Then, both treatments were subjected to 10?mg?l(-1) copper sulfate over a 7-day period. Mortality and serum cortisol, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), sodium, potassium, and chloride levels were recorded at 0, 24, 72, 120, and 168?h post-copper exposure. There was no mortality in the TRP group, whereas the control group mortality was started at 120?h post-copper exposure (21.7?±?7.6?%) and reached 61.7?±?10.4?% at the end of the experiment. Cortisol, glucose, ALT, and AST levels significantly (P?相似文献   
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