فهرست مطالب f. aghamir

One of the most effective ways to preserve biodiversity is to convert conventional systems into organic ones. The organic farming system reduces the negative effects of intensive management. The biomass of the soil ecosystem has different responses in management methods including tillage, fertilizer and defense inputs, and organic modifiers. Understanding the role and responses of biomass in different cropping systems is essential to support sustainable horticultural practices in managing plant-parasitic nematode.

Sampling has been done from two organic farming systems, conventional and pasture, in order to identify the morphology of soil plant parasitic nematodes, soil physicochemical characteristics, and microbial respiration. Plant parasitic nematodes were extracted, killed, fixed, and transferred to glycerin and permanent slides were prepared. The effect of the type of cultivation system on the abundance and diversity of plant parasitic nematodes in common and organic apple and peach orchards compared to pasture were investigated by multivariate analysis of variance (MANOVA) in Xlastat 2020 software.

20 Genera belonging to 11 families of plant-parasitic nematodes were identified, which had different frequencies based on the type of cropping systems and crops. The comparison of the type of organic cultivation system with the common showed that it had a significant effect on the frequency and diversity of plant parasitic nematodes; the highest frequency of the nematode genus in organic peach cultivation system is Gracilacus and the lowest frequency is Scutylenchus genus in common apple cultivation. The abundance of nematode family in organic system is more than common and the abundance of nematode family in peach organic system is more than apple organic system. It should be mentioned that the common apple system is close to pasture in terms of abundance. The abundance of nematode family in the common system of peach is more than the common system of apple. The type of cultivation system had a significant effect on the frequency and diversity of Pratylenchus, Helicotylenchus, Tylenchus, and Rotylenchus genera, while it did not have a significant effect on the  Gracilacus genus. Type of host plant had a significant effect on the frequency and diversity of plant parasitic nematodes definitely in all soil condition variables. The type of host plant was significant on the frequency of all plant nematodes except Tylenchus and a significant effect on the diversity of all except Tylenchus and Rotylenchus. Among all soil factors, microbial respiration, EC, OC, K, P, and texture (percentage of soil particles including sand, silt, and clay) showed a significant effect on all lineages of nematodes.

Significant differences in community structure in plant parasitic nematode communities in three systems were recorded. The results of the present study have shown that the frequency and diversity nematodes are different from the results of other researchers in apple and peach orchards, that plant types and cultivars, basic genotype, or soil management practices affect the composition of plant parasitic nematode community groups. In this study, the abundance and diversity of nematode in the organic system was more than in pasture, and conventional agriculture with more than 10 years of history, including tillage and chemical inputs, and organic matter loss, erosion, and low in the soil agroecosystem. The reduction of the plant parasitic nematode in the conventional system compared to the organic system is caused by the reduction of organic matter, tillage, or chemical inputs. The results showed that the type of product and management practices affect nematode communities. The composition of soil nematode communities is significantly different in organic, conventional, and pasture farming systems. The organic peach and apple system is facing an increase in nematodes more than conventional. It seems that plant parasitic nematodes are sensitive to soil management practices. Soil nematodes are useful indicators to evaluate the intensity of management and sustainable management of horticultural ecosystems on soil ecosystem performance; because they have several feeding habits in soil, and micronutrient networks and play an important role in the food cycle, pest suppression, and regulation of microbial communities. There were high pest pressure of nematodes in the organic peach farming system in comparison to the apple farming system. In this research, apple is better than the peach for organic production in Damavand orchards. In addition, growers consider peaches better than apples due to market and price considerations. With the increase in the demand and price of organic products, the organic system is facing high pest pressure due to fewer management options compared to the conventional system, which requires the development of integrated plant nematode management strategies.

Among the various processes of land degradation, soil erosion is known as a major environmental problem that causes the loss of topsoil and nutrients, reduces fertility, and thus decreases in crop yield. Evaluating and preparing a risk map and estimating the lost economic value due to the loss of soil nutrients can provide the basis for rational planning to prevent and control wind erosion. The aim of this research is to estimate the economic consequences of wind erosion in the Hamoon wetland, which is considered as one of the centers of dust production in the Sistan plain. This research has been done in two stages; first, using the IRIFR model, which is an experimental model to estimate the intensity of wind erosion, an attempt has been made to investigate the erosion intensity, prepare a map of erosion classes (danger), as well as determine the amount of annual sediment production in Hamoon wetland. In the second stage and the economic discussion on the topic, in two parts and using the information obtained from the first stage, using two methods of risk assessment and alternative cost, to prepare a risk map, and the economic value lost due to the loss of the main nutritional elements of the soil action has been taken due to wind erosion in the proposed region. The findings show that Hamoon lagoon has five risk classes in which, the low-risk class has the largest area with 41.15 percent. In terms of economics, from the point of view of the risk map, the largest area of ​​the wetland includes the intensity of risk with 59.93 percent in the very low class, 32.68 percent in the very high class, and 7.36 percent in other classes. The amount of lost economic value of the main soil elements due to wind erosion in the mentioned wetland is estimated to be 994 billion Rials.

A recent report from the United Nation indicates that Iran is witnessing a relative decrease in the prevalence of hunger and an increase in malnutrition. Soil enrichment along with supplementation is one of the simple strategies, away from pollution, available for all people, accessible and profitable, it has the ability to prevent or control nutritional deficiencies. Investigating the relationship between malnutrition and the lack of soil nutrients in Iran's high-risk climates is necessary in line with the soil enrichment program.

The aims of this study were to improve understanding of the relationships between the lack of soil nutrients and the health of population groups, including blood parameters and anthropometric profiles, in various ages and physiology stages (children, adolescents, pregnant and middle-aged women), separated by gender and region (cities and villages) in 11 climate zones of Iran by suggesting a system of assessment indicators and compare multi-factor analyses in heterogeneous variables of various natures.

Findings have shown that the highest synthesis index of anemia in the target groups of the Iranian population was linked to the lack of Fe in soil in all the target groups, lack of vitamin D was linked to the lack of P in soil and lack of Zn was associated to the lack of Zn in the soil. With limited supplementary aids, there are still challenges of soil fertility and malnutrition in provinces of Sistan and Baluchistan, South Khorasan, East Kerman, Bushehr, Hormozgan and Khuzestan.

In conclusion, maps of high-risk regions as well as bioenrichment and supplementary aids are suggested.