جستجوی مقالات مرتبط با کلیدواژه « تجزیه برگ » در نشریات گروه « کشاورزی »

This study evaluated soil and nutrient concentration in different phases of developmental cycle in untouched habitat of oriental beech (Fagus orientalis Lipsky) in Guilan province. Three sampling plots (one ha in each site) were selected, with each plot divided into four sub-plots of 10 ×10 m each. Soil samples were taken from the corner and center of each sub-plot. After air drying, soil properties were measured. At each plot, 10 trees were randomly selected and leaves were sampled from different expositions. The samples were transferred to the laboratory, dried at 40 ° C, ground and further used for the analysis. Nitrogen, phosphorus, calcium, magnesium, potassium, zinc, manganese and iron were measured. Analysis of variance (ANOVA) was conducted on the data. Mean comparisons were carried out by Duncan’s multiple range tests (P ≤ 0.05). Percentage of organic carbon and soil organic matters in decay stage were greater than the other stages. Furthermore, the exchangeable content of K and available P in initial stage was greater in both depths. Mineral nutrition and organic matter in soil surface was greater than soil depth. In addition, leaves analysis showed that the nitrogen in the decay stage was greater than in other stages, whereas the other elements do not notably change. Nutrient uptake was independent of the amount of nutrients in the soil. The results showed that despite differences in the amount of nutrients leaves of beech trees in various stages of evolution the range of nutrients show the health of this ecosystem.

The low solubility of nutrients in the soils of most arid regions, such as Khuzestan, limits or reduces plants growth. Application of organic sulfur to the soil reduces soil alkalinity, increases nutrient absorption and plant growth. This experiment was conducted in a randomized complete block design with split plot design. Experimental treatments consisted of three date palm offshoots weights including 5-8, 8-11, and 11-15 kg in the main plots and four organic sulfur compounds levels as 0, 400, 800, and 1200 gram per plants in sub plots with 4 replication. The study was conducted at Date Palm and Tropical Fruit Research Institute. Results of leaves analysis after performing the experiment showed that organic sulfur compounds improved soil condition around the roots and caused significant increase in leaf nutrient uptake. The highest levels of nitrogen, and potassium content were 2.025 and 2.262 percent and belonged to treatment of 1200 g. organic sulfur per plant. In addition, date palms offshoots weight treatments showed significant differences in growth. The highest rates of growth in trunk diameter and length, seedling length, leaf length, and width were, respectively, 6.7, 16.4, 80.8, 8.4, and 6.8 cm, and were observed in the heaviest offshoots. Organic sulfur treatments had significant effects on stems and leaf growth. The highest rates of growth in trunk diameter and length, seedling length, leaf length and width, were 7.7, 20.1, 85.3, 10.8 and 8.1 cm and 8.6 leaves, belonging to the highest level of organic sulfur treatments. Comparison of the interactions also showed that organic sulfur compounds application at any shoot weight increased growth rate significantly. Finally, the off shoots weight range of 11-15 kg and application of 1200 grams of organic sulfur compounds can be recommended for date palm cv. Mejool offshoots growth.

Studying the soil and eucalypt relationships is essential for eucalypts plantation and avoidance of their negative effects on soil productivity. For this purpose, eucalypt species trial consisting of six species (E. camaldulensis, E. macarthurii, E. maidenii, E. rubida, E. saligna, and E. viminalis) planted in 1983 was conducted. Randomized Complete Blocks with four replicates at 2 x 2 m spacing and total number of 100 seedlings at each plot was used for this research. At each plot, three trees were randomly selected and leafsampling was done for each tree at 1/3 of upper height at the end of summer. The aim of the study was to investigate the nutrients of six eucalypt species planted at Guilan province, Iran. The results showed that there was not significant difference among the replicates regarding the amount of N, P and K, but there was significant difference between the eucalypt species in respect to amount of N. There was significant correlation between K% and P% of eucalypt leaves and some soil characteristics.

Diagnosis and recommendation integrated system (DRIS) and deviation from optimum percentage (DOP) index can be used as efficient methods to interpret the results of plant analysis and the nutritional diagnosis in crops and fruit trees. To establish DRIS norms in seedless grape (Sultana, cv) and compare them with DOP index, leaf samples were collected from 129 vineyards and analyzed for N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B concentrations. The sugar content (brix) of the grape juice was measured as a criterion of yield. On the basis of sugar content, the vineyards were divided into two groups of low and high yielding populations. Standard DRIS norms were established for the different nutrient ratios. DRIS indices were calculated to evaluate nutrients balances and order of nutrients requirements. Sufficiency ranges of macro and micro nutrients were derived by DRIS technique. Means of nutrients concentrations in the high yielding population (high sugar content) were used as reference values for calculating DOP indices. DRIS-derived sufficiency ranges were 2.0-2.8, 0.20-0.27, 1.2-1.7, 1.5-2.1% for,respectively, N, P, K, Ca, and Mg, and 55-138, 40-127, 30-100, 10-20, 30-187 mg/kg for Fe, Mn, Zn, Cu, and B, respectively. DRIS indices showed that, among the macro and micro nutrients in all low yielding vineyards, magnesium and zinc had the most negative index values, respectively. The nutritional balance index (NBI) of DRIS and of DOP (SDOP) were much more than zero in all low-yielding vineyards, indicating that there was imbalance between the absorbed nutrients by grape vines. Comparison of the DRIS indices for the macro and micro nutrients with the DOP indices revealed that Mg and Zn were the most deficient elements in all low-yielding vineyards showing that both methods provide similar information in the interpretation of the results of leaf analysis. To validate DRIS norms and verify the efficiency of DRIS and DOP as methods for improving the interpretation of analysis results of grape leaf, fertilizer experiments should be conducted on seedless grape in a low-yielding vineyard.

The National Botanical Garden of Iran (NBGI) with an area of 145 hectares contains various plants with different ecological requirements, including trees, shrubs, herbs and ornamentals. Weakness and decline of some tree species including Elm trees of botanical garden is one of the problems, which considered as the main priorities to be investigated by the garden authorities. Soil productivity and plant nutrient were concerned to be studied. For this reason, soil samples were taken from three layers of each profile (0-10, 10-30 and 30-100 cm) around Elm trees, after studying the soil profile morphology. Leaf sampling was made at appropriate time in order to test N, P, K at first year and N, P, K, Ca, Fe, Mn and Zn at second year. Results showed that the soil texture was sandy, organic mater was low and pH was alkaline. The mineral elements were lower than the optimum range in soil and tree leaves. It can be concluded that increasing soil organic matter, adding adequate amount of manure and chemical fertilizers to soil and applying appropriate irrigation regime might improve the plants health and growth and prevent their decline.