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71.
Sami Ul-Allah Muhammad Iqbal Muhammad Naeem Muhammad Ijaz Waseem Ashfaq 《Archives of Agronomy and Soil Science》2018,64(12):1678-1689
Wheat (Triticum aestivum L.) productivity is generally affected by water limitation and inadequate nitrogen supply especially under semi-arid environment. The current study was conducted to determine whether the crop yield and irrigation water use efficiency (IWUE) could be manipulated through alteration of nitrogen and irrigation application. To meet the desired objectives, a two-year field study was carried out in 2013–2014 and 2014–2015, in a split-split plot arrangement with three factors i) irrigation in main plots, ii) nitrogen in sub-plots, and iii) twenty genotypes in sub-sub plots on a sandy loam soil. The analysis of variance revealed that the wheat performance was affected by genotypes and alteration of irrigation and nitrogen application with respect to IWUE and final grain yield. IWUE under water stress conditions was observed 56% higher than normal irrigated. Much higher values of IWUE under water stress indicated that the existing optimum water requirements of the crop needs to be revaluated. The regression model indicated that addition of nitrogen and irrigation patterns along with morphological traits cannot explain variation in yield related traits more than 65% under semi-arid conditions. Therefore, for better crop yields in semi-arid environment, more physiological parameters should be considered in evaluation of yield. 相似文献
72.
An 8‐week growth trial was conducted to determine the dietary histidine requirement of the Indian major carp, Cirrhinus mrigala fingerling (length 4.22 ± 0.45 cm; weight 0.61 ± 0.08 g; n = 40). Isonitrogenous (400 g kg?1 crude protein) and isoenergetic (17.90 kJ g?1 gross energy) diets with graded levels of l ‐histidine (2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 g kg?1 dry diet) were formulated using casein and gelatin as a source of intact protein, supplemented with l ‐crystalline amino acids. Twenty fish were randomly stocked in 70‐L indoor polyvinyl circular fish tank (water volume 55‐L, water exchange rate 1–1.5 L min?1) and fed experimental diets at the rate of 5% of their body weight/day divided over two feedings at 08:00 and 16:00 h. Maximum live weight gain (295%), best feed conversion ratio (FCR) (1.48) and protein efficiency ratio (PER) (1.69) occurred at 7.5 g kg?1 of dietary histidine level. When live weight gain, FCR and PER data were analysed using second‐degree polynomial regression, the break points indicated histidine requirements at 9.4, 8.6 and 8.5 g kg?1 of dry diet respectively. Significantly (P < 0.05) higher whole body protein and low moisture values were recorded at 7.5 g kg?1 histidine level. Body fat increased significantly (P < 0.05) with increasing histidine levels. However, at 7.5 and 10 g kg?1 histidine diets body fat did not differ (P > 0.05) to each other. Ash content of fish fed diets containing various levels of histidine did not differ except at 2.5 and 5.0 g kg?1 inclusion levels where significantly (P < 0.05) higher ash was recorded. Protein deposition was also found to be significantly (P < 0.05) higher in the 7.5 g kg?1 histidine diet. Based on the polynomial regression analysis of FCR and PER data, it is recommended that the diet for fingerling C. mrigala should contain histidine at 8.5 g kg?1 of dry diet, corresponding to 21.25 g kg?1 of dietary protein for optimum growth and efficient utilization of feed. 相似文献
73.
Abstract. Among 257 Bangladesh fish ponds investigated, 46% were affected by epizootic ulcerative syndrome (EUS) either fully or partially. Thai silver barb, Puntius gonionotus (Bleeker), culture ponds were worst affected (64%) by EUS, while all Nile tilapia, Oreochromis niloticus (L.), monoculture ponds remained unaffected. Stocking of silver barb for culture, use of piscicides as means of moving predators or unwanted species prior to stocking of cultured species, and culture of fish in previously derelict ponds are factors which significantly affected the probability of occurrence of EUS. Choice of species other than silver barb and use of lime during the post-stocking period significantly affected the probability of pond stocks being less adversely affected by EUS. 相似文献
74.
Purpose
Lead (Pb) pollution is appearing as an alarming threat nowadays in both developed and developing countries. Excessive Pb concentrations in agricultural soils result in minimizing the microbiological activities which leads to the decrease in crop production. A pot experiment was conducted with the purpose to examine the deleterious effect of Pb on microbiological index under spinach cultivation.Materials and methods
Pb was added to 5 kg soil in each pot (with 6 seeds/pot) using Pb(NO3)2 at the rate of 0, 150, 300, 450, and 600 mg kg?1 with three replications in completely randomized design. All soil microbial, enzymatic, and chemical properties and plant growth parameters and nutrient uptake were measured by standard methods.Results and discussion
Both soil and plant measured parameters decreased after the addition of Pb (150, 300, 450, and 600 mg Pb kg?1 soil) treatments with the passage of time (from 15 to 60 days) compared with control (CK). However, high Pb levels had more suppressive effect, therefore, highest Pb level (600 mg Pb kg?1 soil) significantly (P?<?0.05) decreased the microbial biomass carbon (5.59-fold); microbial biomass nitrogen (N; 11.71-fold); microbial biomass phosphorus (P; 25.1-fold); dehydrogenase (4.02-fold); phosphatase (9.40-fold); urease (9.26-fold); pH (1.40-fold); spinach shoot (2.17-fold) and root (2.54-fold) length; shoot (2.36-fold) and root (2.69-fold) fresh weight; shoot (3.90-fold) and root (3.50-fold) dry weight; chlorophyll content (5.60-fold); carotenoid content (4.29-fold); plant macronutrients uptake, i.e., N (4.38- and 2.97-fold), P (3.88- and 6.58-fold), K (3.88- and 4.6-fold), Ca (6.60- and 6.70-fold), and Mg (5.57- and 4.45-fold); and plant micronutrient uptake, i.e., Zn (2.39- and 3.05-fold), Cu (3.70- and 2.62-fold), Fe (4.13- and 3.23-fold), and Mn (4.17- and 4.09-fold) in spinach shoot and root, respectively. Conversely, highest Pb level, i.e., 600 mg Pb kg?1 soil significantly (P?<?0.05) increased the biomass carbon (C)/nitrogen (N) (4.69-fold) and C/P (6.01-fold) ratios, soil extractable Pb (5.87-fold), and Pb uptake in spinach shoot (3.58-fold) and root (4.38-fold), respectively, at the end of the experiment, i.e., day 60.Conclusions
Pb contamination significantly decreased the soil microbial and enzymatic activities, pH, spinach plant growth, and nutrients uptake in all the samples spiked with Pb. The degree of the influence increased with the increased Pb concentrations and incubation time, showing that Pb threshold is strongly associated with the extent of Pb concentration and time to accumulate. The soil microbial biomass, enzymatic activities, pH, and spinach physiological indices, could be used as a sensitive indicators to reflect environmental stress in soil ecosystems. 相似文献75.
Md. Saiful ISLAM Md. Kawser AHMED Md. Habibullah Al-MAMUN Dennis Wayne EATON 《土壤圈》2020,30(2):201-213
Trace metal contamination in soil is of great concern owing to its long persistence in the environment and toxicity to humans and other organisms.Concentrations of six potentially toxic trace metals,Cr,Ni,Cu,As,Cd,and Pb,in urban soils were measured in Dhaka City,Bangladesh.Soils from different land-use types,namely,agricultural field,park,playground,petrol station,metal workshop,brick field,burning sites,disposal sites of household waste,garment waste,electronic waste,and tannery wast,and construction waste demolishing sites,were investigated.The concentration ranges of Cr,Ni,Cu,As,Pb,and Cd in soils were 2.4–1258,8.3–1044,9.7–823,8.7–277,1.8–80,and 13–842 mg kg^-1,respectively.The concentrations of metals were subsequently used to establish hazard quotients(HQs)for the adult population.The metal HQs decreased in the order of As>Cr>Pb>Cd>Ni>Cu.Ingestion was the most vital exposure pathway of studied metals from soils followed by dermal contact and inhalation.The range of pollution load index(PLI)was 0.96–17,indicating severe contamination of soil by trace metals.Considering the comprehensive potential ecological risk(PER),soils from all land-use types showed considerable to very high ecological risks.The findings of this study revealed that in the urban area studied,soils of some land-use types were severely contaminated with trace metals.Thus,it is suggested that more attention should be paid to the potential health risks to the local inhabitants and ecological risk to the surrounding ecosystems. 相似文献
76.
Hong-sheng Wu Yang Wang Wei Bao Dong-yang Liu Waseem Raza Qi-wei Huang Ze-sheng Mao Qi-rong Shen 《Biology and Fertility of Soils》2009,45(4):443-447
To assess the influence of phenolic acids from plant root exudates on soil pathogens, we studied the effect of sinapic acid
added to chemically defined media on the growth and virulence factors of Fusarium oxysporum f. sp. niveum. Sinapic acid inhibited the growth and conidial formation and germination of F. oxysporum f. sp. niveum by 6.7–8.8% and 11.2–37.3%, respectively. Mycotoxin production by F. oxysporum f. sp. niveum was stimulated by 81.6–230.7%. Pectinase, proteinase, cellulase, and amylase activities were stimulated at a lower concentration
of sinapic acid, while they were inhibited at a higher concentration. It is concluded that sinapic acid inhibited the growth
and conidial germination of F. oxysporum f. sp. niveum and decreased the pathogenic enzymes’ activity at higher doses. 相似文献