Showing 9 results for Malakouti
M. Kavoosi, M. J. Malakouti,
Volume 10, Issue 3 (fall 2006)
Abstract
Potassium is one of nutritional element that has an important effect on the quantity and quality of rice plant. Knowledge about the K critical level and plant response to different application rate of K, can effectively help with the proper use of this element. Therefore, in this study potassium (K) critical level for rice (Khazar variety) and prediction equation for grain yield were determined in 21 rice fields of Guilan provience during 2001-2002. After land preparation, 6 experimental plots (4×5m) were constructed in each selected field. Nitrogen and phosphorus were applied before transplanting, based on soil test from urea and triple superphosphate, respectively. Potassium was applied in different rates including 0, 100, 200, 300, 400, and 500 kg ha-1 of K2O as muriate potassium. Khazar variety was transplanted in a space of 25×25cm, just after fertilizing of plots. Plots were harvested in 5 m2 at the end of maturity stage from the first node above the ground, and grain and straw were measured separately. Statistic analysis was done on grain weight based on 14% moisture. The results showed, that effect of different K fertilizer application in 5% and the effect of soil type in 1% were statistically significant on the grain yield. The mean increase of grain yield in responsive fields to K application was 982 kg ha-1. The results also showed that the responses of rice fields with available K less than 100 mg kg-1, 100-160, and more than 160 mg kg-1 to KCl application were high, moderate and low, respectively. Potassium critical level based on 90% relative yield was determined as 110 mg kg-1 of soil . In final relative yield, prediction equation, available potassium, potassium content of irrigation water, and rate of KCl fertilizer application entered positively in the equation, while available phosphorus showed negative effect on relative yield.
H. Khoshghalb, K. Arzani, M. J. Malakouti, M. Barzegar,
Volume 12, Issue 45 (fall 2008)
Abstract
Changes of the main sugars and organic acids content in Asian pear (Pyrus serotina Rehd.) Cultivars ‘KS’9 and ‘KS’13 grown in Tehran were studied from fruit set to maturity. The main sugars and organic acids content in fruits were determined 1 and 2 months before harvest, at the time of harvest and 1, 2 months after harvest time using High Performance Liquid Chromatography (HPLC). Fruits were stored at 2˚C and 80-85% relative humidity (RH). There were significant differences between cultivars and time of fruit harvest in terms of sugars and organic acids content. In both studied cultivars, fructose, glucose and sorbitol increased from the first fruit sampling to one month after harvest (1 to 9% FW) and then decreased. Sucrose content decreased from 2 months before harvest to 2 months after harvest time (3 to 0.75% FW). In both studied cultivars organic acids content increased at the time of pick-up and then decreased. The highest organic acids contents in the studied cultivars were malic and ascorbic acids (345 and 41.1mg 100g-1FW in ‘KS’9 and control, respectively). The relationship between low sugar and organic acid content in fruits showed the highest correlation (0.8 to 1) in both cultivars among low flesh firmness, low total soluble solid (TSS), low dry weight and high internal browning determined in this study. Results indicated that high content of sugars and organic acids in fruit led to delayed internal browning. Asian pears with a low ascorbic acid concentration are probably more susceptible to internal browning. High correlation was observed between high sugars content and high fruit colour.
M. Gholamhoseini, M. Aghaalikhani, M.j. Malakouti,
Volume 12, Issue 45 (fall 2008)
Abstract
In order to study the effect of various amounts of nitrogen (N) and Iranian natural zeolite on the quantitative and qualitative forage yield of winter canola (Brassica napus L.) in light soil, a field experiment was conducted on research farm of Tarbiat Modares University, Tehran, during 2006-2007. Treatments were arranged in the form of RCBD with 3 replications. The experimental treatments were based on factorial various levels of zeolite (0, 3, 6 and 9 t.ha-1) and nitrogen (90, 180 and 270 kg ha-1) in urea form. Seeds of canola (Brassica napus L. cv. Okapi) were sown on October 2, and fresh forage was harvested at the time of silique formation (170 DAP). Results showed that the effect of N and zeolite on forage quantitative attributes including biomass, leaf and stem dry weight and leaf area index were statistically significant. In addition, forage qualitative traits including crude protein percentage and calcium percentage in plant mass were significantly affected by N and zeolite. Increasing application of N fertilizer caused increase in N leaching, and with increasing zeolite application, N leaching reduced. The interaction of two factors for all parameters was not significant. The most increasing effects on forage yield and quality were gained using 270 kg N ha-1 in combination with 9 t. Zeolite ha-1. More detailed studies are strongly recommended to investigate the effects of integrated application of chemical fertilizer and natural zeolite.
M Valipour, M Karimian Eghbal, M.j Malakouti, A Khosh Goftamanesh,
Volume 12, Issue 46 (1-2009)
Abstract
Salinization and alkalization are considered spatiotemporal dynamic soil degradation processes. In order to investigate the effects of agricultural activities on land degradation and soil salinity, Shamsabad area in Qom province was selected. Aerial photos (1955) and satellite images (1990-2002) were used to examine the changes in land use. Soil samples were collected from 25 locations in the study area from 0-50 cm and 51-100 cm depth at each location. For comparative purposes, sampling locations in this study were similar to locations used for salinity study in 1983. For each sample, pH, electrical conductivity (ECe), base saturation percentage, exchangeable sodium, lime and texture were measured. Land use and salinity maps were created by using geographic information system (GIS) softwares. Results revealed an increase of 9.5 times in cultivated lands in 47 years. Increase in agricultural activities in the study area has also intensified the pressure on water resource in the area, lowering ground water tables and degrading water quality. In the 0-50 cm soil depth, the average soil ECe was 6.5 dS/m in 1983, which increased to 10.7 dS/m in 2005. If soil salinity trend and pressure on water resources continue, large part of Shamsabad area is expected to change to desert in near future years.
M Malakouti, M Babaakbari, S Nezami,
Volume 13, Issue 49 (Water and Soil Science 2009)
Abstract
To increase grain yield, nitrogen use efficiency (NUE) and nitrogen apparent recovery fraction (NARF) in wheat (Triticum aestivum L.), an experiment was carried out in Karaj Soil and Water Research Station farm for two consecutive growing seasons in 2004-05 and 2005-06. The experimental design was RCBD with 6 treatments (T1= Control T2= 150 kg ha-1 of N as urea in 3-split applications T3= 1/3 N as SCU as the base fertilizer + 2-split urea applications T4= 150 kg ha-1 N as SCU as the base fertilizer T5=150 kg ha-1 of N as urea in 2-split applications and T6=1/3 N as complete fertilizer as the base fertilizer +2-split urea applications) in the first year and 7 treatments (T1= Control T2= 180 kg ha-1 of N as urea in 2-split applications T3= 180 kg ha-1 of N as urea in 3-split applications T4= 180 kg ha-1 N in 5-split urea applications T5 = pre-plant urea + 4-split urea applications T6= 1/3 N as SCU as the base fertilizer +4-split urea applications and T6=1/3 N as complete fertilizer as the base fertilizer +4-split urea applications) in the second year with 3 replications. In the second year, N rate was increased from 150 to 180 kg ha-1, adding the existing extra nutrients in complete macro and fertilizers to other treatments and N split-application was increased up to four times. After harvesting, grain yield, NUE and NARF were measured. The results of first year revealed that the yield, NUE and NARF for T2 (5145 kg ha-1, 13.8 kg kg-1, 41.2%, respectively) and T6 (5067 kg ha-1, 13.2 kg kg-1, 38.2.2%, respectively) were increased significantly at 1% level. In the second year, the maximum grain yield (6335 kg ha-1), NUE (16.2 kg kg-1) and NARF (50%) were obtained again from T6 treatment. Higher yield, NUE and NARF in the second year were mainly due to higher N rates and more N split applications. The economic returns for these substitutions, even without considering any fertilizer subsidies, the averages turned out to be 14, 8 and 4 in these treatments, respectively. Overall results revealed that the substitution of complete macro and SCU fertilizers with pre-plant urea is advisable in wheat production areas. Therefore, it is recommended that the experiment be further tested and evaluated in some wheat growing provinces.l results.
N Ghanavati, M Malakouti, A Hossein Por,
Volume 13, Issue 49 (Water and Soil Science 2009)
Abstract
Correlation between components of Q/I and wheat (Triticum aestivum L.) growth indices was studied in a greenhouse experiment during 2003-04 growing season. Eighty soil samples (0 – 30 cm depth) were collected randomly in farms around the Abyak region, Ghazvin province. Twenty-one samples were then selected based on soil texture and NH4OAC-K. The research included treatments of 21 soils and two potassium (K) levels (0, 100 mg/kg) and was conducted in a factorial manner in a randomized complete block design with three replications for studying correlations between Q/I and treatments. Effect of potassium application on the wheat growth was found to be significant at 5% level. The effect of soil properties on wheat growth was also found to be significant at 1% level. However, the interaction of K and soil was not significant. There were no significant differences among the different equilibrium time intervals. The soil potassium buffering capacity (PBCK) values were strongly correlated with CEC (r =0.996**), clay content (r = 0.921**) and moisture saturation percentage (r = 0.811**). Final equation derived from stepwise regression for prediction of PBCK was as follows: PBCK = 7.419 CEC –19.743 R2adj = 0.782** The equilibrium potassium activity ratios (ARke) were strongly correlated with soluble potassium (r =0.846**), NH4OAC-K (r =0.730**), SP (r = 0/794*), OC (r = -0.477ns) and clay content (r=-0.602*). Similarly, readily exchangeable potassium (ΔK0) was strongly correlated with ammonium acetate extractable potassium (r = 0.871**), soluble potassium (r = 0.778**), saturation percentage (r = 0.551*), organic carbon percentage (r=-0.045ns) and clay content (r=-0.206ns). There was no significant correlation between ΔK0 and ARKe with potassium uptake values by wheat. In contrast, there was a strong correlation between PBCK values and potassium uptake by wheat (r = 0.729**), and relative wheat yield (r = 0.735**). There was no significant correlation between Q/I parameters when KCl and K2SO4 were used, and the soil physicochemical properties. However, Q/I parameters obtained from KCl showed a higher correlation with wheat plant's growth indices.
Sh. Kiani, Gh. Zadeh Dabagh, M.j Malakouti, A. Alizadeh ,
Volume 14, Issue 51 (spring 2010)
Abstract
Gray mold, caused by Botrytis cinerea, is a serious disease of cut rose flowers (Rosa hybrida L.) in Iran. In order to elucidate the effects of different potassium and calcium levels in nutrient solution on susceptibility of cut rose flowers to gray mold, this experiment was carried out as factorial design in a randomized complete block with four replications at Safi Abad Agricultural Research center in 2008 for one year. In this experiment, rose plants were grown and subjected to three levels of potassium (1.0, 5.0 and 10.0 mM) in combination with two levels of calcium (1.6 and 4.8 mM) under hydroponic condition. Rose flowers from two consecutive harvesting periods were sprayed with the conidial suspension (104 spore/ml) of B. cinerea isolate. At the end of experiment the disease severity was recorded and analyzed. The results indicated that application of 10.0 mM K in the nutrient solution led to increasing rose disease severity to gray mold (30.4 % day-1) compared to 1.0 mM (24.8 % day-1) and 5.0 mM (26.2 % day-1) of K levels (P< 0.01). The increased susceptibility was associated with a decreased concentration of Ca in the rose petals. Correlation analysis revealed that susceptibility of rose flowers to gray mold significantly increased with K to sum cations ratio in the nutrient solution (r = 0.94*). The increase of Ca supply from 1.6 to 4.8 mM resulted in decline of disease severity from 29.6 to 24.6 % day-1 (P< 0.01). Therefore, balanced application of potassium and calcium (5.0 and 4.8 mM, respectively) is recommendable for preventing antagonistic effects between them and reducing of rose gray mold intensity under hydroponic conditions.
M. Nourzadeh, S. M. Hashemy, M. J. Malakouti,
Volume 15, Issue 57 (fall 2011)
Abstract
Electrical conductivity and acidity of soil are the most important chemical factors of soil for agriculture. The nature of soil is in such a way that its change has a continuous form. The method that can take into account this continuity will be able to show a better picture of change in soil characteristics. Objectives of this research are to investigate the relations between measured electrical conductivity and soil acidity of Qom plain, and clustering, compare the clustering methods, determine the optimum numbers of cluster, and to zone the clusters in the study area. Accordingly, two fuzzy clustering methods FCM and GK, were used for data mining and clustering of 465 measured data. For estimating the appropriateness and comparison of two methods, some criteria including Partition Coefficient, Classification Entropy, Partition Index, Separation Index and Xie and Beni's Index were used. Data mining results showed that the optimum number of clusters for FCM and GK method was 15 and 17, respectively. After investigating the results of clustering and based on the criteria of appropriateness, it was indicated that GK was the best clustering method. According to this method, 295 data from 465 measured samples had more than 40 percent of membership function. So, 9 clusters from 17 clusters had more than 20 members. Then salinity-alkalinity zoning based on GK method to show the clusters distribution better in the study area was prepared. This prepared fuzzy map explained that most of Northwest and west belonged to cluster 1 and eastern parts of study area include belonged to cluster 17. Based on this, salinity-alkalinity and the ensuing soil degradation in east of study area is more likely than the west of it.
M. Ayoubi, R. Sokouti, M. J. Malakouti,
Volume 20, Issue 76 (Summer 2016)
Abstract
This study is aimed to investigate the spatial variation of soil macronutrients such as phosphorus, potassium and organic matter using different methods of Geostatistics and Geostatistical method combined with Fuzzy logic to estimate the values of this element to provide a spatial distribution map for the proper distribution of fertilizer in the plain of Uremia. Spatial variations in soil nutrients are natural but knowing these changes for careful planning and management particularly in the agricultural lands is simply inevitable. This information is necessary to increase the profitability and sustainable agricultural management. Therefore, to estimate the changes in the elements of places not sampled, the Kriging, Fuzzy Kriging, Cokriging and Inverse Distance Weighting methods have been used in GS +. In this study, Matlab 9.1 software was used to fuzzification of the data and GIS was used for the final mapping. The parameters MAE, MBE and RMSE were used to compare these methods. The results showed that the combined method of Fuzzy Geostatistic with the mean absolute error values for the elements phosphorus, potassium and organic matter i.e. 0.17, 0.18 and 0.18, respectively, is recognized as the preferred method based on which zoning maps have been prepared for P, K and OC in GIS.
