Iran Agricultural Research
Year:2018 | Volume:37 | Issue:2|Papers Count:14

The agricultural sector encompasses activities that are exposed to diverse risks. Risks in the agricultural sector are unavoidable but manageable. Crop insurance is a management tool in the agricultural sector. Crop insurance is a strategy to cope with the production risks of the agricultural sector and to secure farmers’ income in the future. Mango is a major horticultural and exporting crop in Sistan and Baluchestan province and in Chabahar with a key role in local economy. The present study aimed to use cross-sectional data of 2016-2017 for 285 mango farmers to explore the phenomenon of moral hazard and its economic consequences. Discriminant analysis and t-test were applied for economic modeling and data analysis. The results did not show any moral hazards in the insured group. So, we can improve the crop production and productivity by focusing on the role of the insurance. The determination of premium on the basis of the regional conditions and farmers’ economic status can have desirable impacts on production.

Field experiments were conducted to determine the relationship between plant leaf area as the dependent variable with leaves number, leaf dry weight, and total vegetative components dry weight and plant height as the independent variables. Treatments were two tillage systems (conventional and no-tillage) as main plots, and seven sowing dates (11 May, 18 May, 25 May, 1 June, 8 June, 15 June and 22 June) as sub plots. This research was carried out at the Research Farm of Shiraz University during 2014 and 2015 growing seasons. The interaction between sowing date and tillage system was significant. The highest leaf area, leaf number, leaf dry weight, total dry weight and plant height were obtained in earlier sowing dates (11 May, 18 May, 25-May and 1-Jun) in both tillage systems and the lowest were obtained in the latest sowing date (22 Jun) in no-tillage in both years. Using polynomial equation for determining algometric relationship between leaf area and vegetative characteristics showed a significant relationship between leaf area with leaf number (R2=0. 96 and R2=0. 98), leaf dry weight (R2=0. 98 and R2=0. 98), total vegetative components dry weight (R2=0. 96 and R2=0. 96) and finally plant height (R2=0. 98 and R2=0. 95). These allometric relationships contribute to a better understanding of plant growth and development in corn, which is necessary for optimal management of the crop and for genetic improvement.

Measurement of irrigation water in agricultural areas is necessary, especially, in arid and semi-arid regions. Long-throated flumes have been used to measure irrigation water and are known to be inexpensive devices with high performances. In these structures, head-discharge tables are predicted theoretically with no need to calibrate. In this study, the model of LOTF (LOng Throated Flumes) was developed in VB. net programming language, in which, friction head loss and h-Q (h is head at measuring station and Q is discharge) tables were predicted by using the Manning's equation. The predicted tables of h-Q by the LOTF model were perfectly similar to the results of Win Flume and HEC-RAS model which are universally used for these flumes and open channel flow, respectively. Calculated h-Q tables in trapezoidal flumes with two different side slopes of 0 and 1, 0 and 2, and 0 and 4 were computed by the LOTF and HEC-RAS models and were the same as those predicted by the WinFlume model with equal average of these side slopes of channel. At a water depth, in trapezoidal sections with different and equal average side slopes, the resulted h-Q tables in the three models were the same.

The aim of this study is economic analysis of supplemental irrigation (SI) for rain-fed fig trees in the south of Iran, with and without micro-catchment water harvesting systems (MCWHS). Under no MCWHS, by decreasing about 55 % of applied water, the fig yield decreased about 28% and net income increased twice compared with the maximum yield condition. In general, the optimal amount of SI water would be lowered by using MCWHS in comparison with no using MCWHS. By using MCWHS, decreasing about 50 % of applied water causes about 14 % decrease in fig yield and net income increased twice compared with maximum yield condition. In order to obtain high net profit with a given amount of annual rainfall, the amount of optimal SI water decreased by increasing the unit price of water. An equation is proposed for the prediction of annual precipitation which may be used for planning SI for the fig trees in the study region.

The critical period of weed control is a part of crop life cycle during which weeds must be kept weed-free to avoid yield losses due to competition. In order to evaluate the effect of deficit irrigation on critical period of redroot pigweed (Amaranthus retroflexus L. ) in sunflower (Helianthus annuus L. ), an experiment was carried out as split plot based on randomized complete block design with three replications at the experimental farm of College of Agriculture, Shiraz University, during 2010 and 2011 growing seasons. Factors were water deficit at three levels (100%, 75% and 50% of field capacity) as main plots and weed interference periods in weedy and weed-free plots at five sunflower growth stages (8-leaf, 12-leaf, head emergence, flowering and maturity) as subplots. Results showed that water deficit decreased grain yield and grain yield components in both years. Critical period of redroot pigweed in normal irrigation with accepting 5% yield loss in sunflower was 35-86 DAP (days after planting) in the first year and 49-94 DAP in the second year. By decreasing irrigation water to 75%FC and 50%FC, the length of critical period increased to 34-100 and 32-105 DAP in the first year and 50-101 DAP and 44-98 DAP in the second year of the study, respectively. Generally, our results showed water deficit extended the length of critical period of redroot pigweed in sunflower.

The enrichment of bedding for vermicomposting systems with organic and inorganic additives is a technique which can promote the quality of produced vermicompost. Phosphate rock and fishmeal are two available and low-cost substances which can be provided easily and inoculation of vermicompost with phosphate solubilizing microorganisms (PSMs) can enhance the availability of their nutrients. In this research, the effect of using phosphate solubilizing bacteria (PSB) (Pseudomonas fluorescens) by adding phosphate rock (0 and 1% W/W) and fishmeal (0 and 1% W/W) on some chemical and biological properties of vermicompost was studied under greenhouse conditions with a factorial arrangement in a completely randomized design with three replications. Phosphate rock application and PSM inoculation decreased N concentration while fishmeal increased it. P concentration increased by adding phosphate rock, fishmeal or PSB or their co-applications. Fishmeal increased micro-nutrients concentration except for Fe. Phosphate rock increased Fe concentration and decreased other micro-nutrients concentration. Electrical conductivity (EC) increased by adding phosphate rock but decreased by fishmeal application. Phosphate rock and fishmeal increased pH. Phosphate rock and PSB decreased the number and weight of earthworms and the number of cocoons. Fishmeal application increased the number and weight of earthworms and number of cocoons. Results indicated that enrichment of vermicompost bedding by additives could increase some essential nutrients and change the growth and biomass of earthworms.

Overgrazing accelerates soil and vegetation degradation in rangelands. This study aimed to assess livestock pressure on natural resources of Khuzestan province, located in the south western part of Iran, using Geographic Information System (GIS) tools and a model-based procedure. FAO/UNEP Model which uses a ratio of potential carrying capacity of region to current livestock population density as an Index for livestock pressure was selected for this purpose. However, the model was modified in this study to achieve a better estimation of pressure index according to the actual conditions of the region. Parameters used to modify this methodology were: Topographic and Local parameters. Local parameters were annual consumption for livestock unit in the study area, dependency of each livestock to pasture, number of livestock unit for each animal and land use map. Hazard map of pressure of livestock was prepared after overlying and calculating different parameters in a GIS. According to the results, hazard classes of severe and very severe included about 70% of natural resources in the study area. Areas including higher classes of hazard severity were identified in the west, center and south east part of the region, mostly. This is because of low potential of natural rangeland to grow enough forage and also a high number of livestock.

Sustainability and environmental management are the most cited ideas linking the environment and development. The sustainability of natural resources depends upon our paradigm and related approaches to the relationship between society and the environment. Efficient management is a primary task due to the pressure on nature. Ecological footprint analysis has been introduced as an appropriate environmental management tool to address the environmental challenges that Iran is facing and to determine solutions. It is a resource accounting tool which could be applied in environmental planning and management focusing on natural resource consumption. Reviewing and analyzing the biocapacity (BC) and ecological footprint (EF) of Iran in the timeline of 1962-2011 was the main purpose of the study. Based on the findings, EF trend of the country has an increasing trend over time while the BC has a reverse trend. The consumption by farmers and other agricultural actors from resources has been greater than the country`s regenerative capacity regarding the BC and EF of cropland. The sustainability gap has been greater over time due to population growth and other related factors. Despite the different environmental rules and regulations, there was no improvement or progress in sustainability achievement in Iran. Returning to the condition in which EF equals BC is the least action required to decrease the pressure on nature. Effective and suitable environmental policies are needed in order to address the policy gap as well as reduce the EF level to the balance point by appropriate executive activities covering the implementation gap.

The aim of this study was to investigate the effects of “ Arbuscular mycorrhizal fungi” (AM fungi) density and different growing media on the growth, photosynthesis parameters and yield of sweet pepper under greenhouse conditions. The experiment was conducted as a factorial plan based on control randomized design (CRD ) by using three growing media, Perlite (PR) and cocopeat (Co) (PR50: Co50 V: V) (C), PR25: Co50: vermicompost (V) 25 (C+V25) and PR25: Co25: V50 (C+V50), and three levels of AM fungi inoculation (0, 1000 and 2000 spores) with three replications. Results indicated that AM fungi inoculation and mixture of vermicompost increased shoot and root fresh weights, Total Suspended Solids (TSS), fruit fresh and dry weights in the C+V50 compared to other treatments. Fruit yield increased more than 100 and 94. 95% with AM-fungi inoculation with 2000 spores at C+V25 and V50 treatments, respectively. Mycorrhiza dependency decreased with high application rate of vermicompost, and vermicompost dependency was the highest in non-inoculated plants. With AM-fungi inoculations, the chlorophyll level (SPAD values) was increased in C+V25 by 100%. Photosynthesis rate was increased in C+V25×M1 significantly compared to other treatments. Nitrogen, phosphorus, and potassium concentrations significantly increased by mycorrhiza inoculation in the high vermicompost ratio.

During rice growing season, the symptomless rice seeds from different paddy fields in Guilan province, Iran, were collected. After isolation of epiphytic and endophytic bacteria, 39 isolates including 19 epiphytes and 20 endophytes were selected based on the predominant characteristics. Five Operational Taxonomic Units (OTUs) were obtained based on PCR-RFLP of 16S r-DNA in these isolates. According to biochemical tests and partial sequencing of 16S-rDNA, in both epiphyte and endophyte bacteria of rice seeds, the most populated OTUs (V and II) were identified as Pantoea ananatis and Pseudomonas oryzihabitans, respectively. Six representative isolates from these two OTUs were selected to be evaluated for their abilities for rice seed germination and growth enhancement. Among them, P. oryzihabitans was not beneficially effective. However, JpB1 isolate of P. ananatis was considered to be the most effective plant growth promoting isolate, since it showed stable beneficial effects on most surveyed characteristics in both rice seed germination and growth enhancement experiments. Although, OpB3 isolate of P. ananatis produced IAA in higher amount and solubilized phosphate more than the other isolates followed by JpB1 and P. ananatis L3pB3, it was not beneficially effective on rice seed germination.

Several species of aphids cause severe damage to citrus in the north of Iran. Predatory insects play an important role in biological control of the pests in citrus orchards. In this study, potential predatory insects of citrus aphids, Aphis spiraecola, A. gossypii and Toxoptera aurantii, were identified and their seasonal population dynamics on Citrus unshiu and C. sinensis were investigated during 2016-2017. Overall, four species were identified as dominant predatory insects of citrus aphids in Mazandaran province including Xanthogramma pedissequum (Syrphidae), Scymnus subvillosus, Coccinella septempunctata (Coccinellidae), and Aphidoletes aphidomyza (Cecidomyiidae). Among these species, X. pedissequum and S. subvillossus were more abundant predators in the C. sinensis and C. unshiu orchards compared to the two other species. The predatory insects were observed when means of environmental temperature was about 15-20º C. Population fluctuations, population densities and presence periods of the predatory insects were different on the two host plants. Results of this study can be used in integrated pest management programs of citrus aphids in citrus orchards in the north of Iran.

Intercropping is a sustainable practice to achieve higher production with the aim to limit external inputs. A field experiment was conducted at the research farm of the Faculty of Agriculture, University of Maragheh, Maragheh, Iran, during 2016 growing seasons with ten treatments to evaluate the yield, analyze the competition and insect’ s assemblages in sunflower (as main plant)/soybean (as companion plant) intercropping. Treatments included sunflower sole cropping, soybean sole cropping, replacing intercropping sunflower with soybean (50: 50, 34: 66, 66: 34, 40: 60, 60: 40, 25: 75) and additive intercropping of two plants (100: 50 and 100: 100%). Results showed that the highest sunflower grain yield (275 g m-2) was obtained in sunflower monoculture that was not significantly different with intercropping ratios of 25: 75 and 60: 40. Also, the highest and lowest grain yield of soybean was achieved in soybean monoculture (130. 1 g m-2) and ratio of 100: 50 (48. 5 g m-2), respectively. The highest land equivalent ratio, monetary advantage index and intercropping advantage value was obtained in intercropping ratio of 25: 75. Moreover, in all cropping patterns the aggressivity (A) and crowding ratio (CR) values of sunflower were higher than soybean, indicating that sunflower was the dominant species. Also, the highest density for herbivores was recorded in soybean monoculture and the families of Thripidae (37. 60-43. 87%) and Cicadellidae (34. 01-37. 71%) had the most relative density. Furthermore, intercropping of sunflower with soybean increased pollinators and natural enemies’ abundance compared with monocultures. Overall, based on the ecological, agronomical and economical indices intercropping sunflower with soybean with ratio of 25: 75 is a feasible alternative method to achieve similar production with respect to monocropping.

Sugarcane is one of the severely perishable crops that is used as raw material for white sugar production. Sucrose content of the sugarcane which is of high commercial value decreases in quality due to pre-harvest burning, high ambient temperature, kill-to-mill delays as well as microbial contaminations. Delays in sugarcane transportation are the most important risks which can affect the quality and quantity of the product. Delay in milling of the harvested sugarcane is caused by various reasons in agro-industry units including factory downtime, breakdowns of tractors in the waiting line at factory, tractor accident in factory yard and staff shift changes creating long queues. In order to reduce delays, the present study attempted to forecast arrival and service level of tractor drawn carts which transfer burned or cut canes from farm to mill. The univariate ARMA models were applied to forecast arrival and service level. The RMSE and MAPE were also used to evaluate precision of our forecast. The results of models demonstrated that ARMA(4, 3) and ARMA(4, 2) models are suitable for arrival and service level of tractor drawn carts, respectively. The predicted values trend of arrival, and service level truly reflected the actual values of arrival and service level as well as queue system tendency. The values of MSE, RMSE and MAPE that indicate accuracy of the forecasted carts arrival and service level were relatively low. The estimated models can be used to forecast values of arrival and service levels of tractor drawn carts for subsequent hours during harvest season.