Iran Agricultural Research
Year:2003 | Volume:22 | Issue:1|Papers Count:8

Farmers, particularly in developing countries, operate in an uncertain decision making environment. Variations in crop yields and fluctuations in input and output prices are important elements of risk in agriculture. Various risk -programming techniques have been developed to model risk in decision making under uncertainty. The purpose of this study was to examine and evaluate major alternative methods of incorporating risk in decision models. An extension of the method of direct utility maximization then was used to generate an efficient set of farm plans for the small, medium and large representative farms, using the concept of stochastic dominance with respect to a function. The model incorporates farmers risk preferences, revenue fluctuations and resources restrictions in agricultural planning. Results of this study demonstrated the merits of this technique particularly when sufficient information is not available to estimate the individual utility function for each representative farm. The optimum plans identified the changes in crop activities to seek a trade-off between maximizing expected value of total net revenues as well as minimizing the risk of undertaking crop activities.

Effect of replacing alfalfa hay with wheat straw in iso-fibrous (35% NDF) diets with different levels of dietary cation-anion balance (DCAB) was studied by using eight mid-lactation Holstein cows blocked according to parity and milk yield in a 4x4 replicated Latin Square design. The treatments were 1) alfalfa hay (AH) with +35 meq, 2) wheat straw (WS) with +35 meq, 3) WS with +45 meq, and 4) WS with +55 meq (Na` + K+)CI-11t10 g diet dry matter (DM). Treatment periods were 15 d with the first 10 d serving as an adaptation period. Forage to concentrate ratio decreased from 43:57 to 26:74 when WS was substituted for AH. Apparent digestibility of DM, organic matter (OM), and nitrogen (N), and DM disappearance rate at 24 h post-feeding decreased significantly in WS containing rations (P<0.01), but was not increased with increasing dietary cation-anion balance (DCAB) in WS rations. No significant differences were observed in DM intake. Actual milk yield and 4% fat-corrected milk (FCM) were not affected by the treatment. Milk fat percentage was significantly (P

The influence of the type of lactic starter inoculation on the physicochemical and sensory properties of Iranian white cheese was investigated. Five treatments of starters were examined as follows: A) Lactobacillus casei 01+ aromatic mesophile CH-N-01 (1:1): B) Aromatic mesophile CH-N01 + thermophile CH-1 (1:1): C) Thermophile CH-1; D) Thermophile CH-1 + mesophile 54 (1:1); E) Mesophile 54. The cheeses were analyzed for sensory characteristics moisture, pH, total protein, soluble nitrogen, acid degree value and hardness. Cheese samples treatments were taken in a completely randomized design. The results indicated that the type of starter bacteria and storage time had a significant effect on composition and hardness. The pH value in all treatments dropped drastically in such a way that curds made in intreatments B, C, and D reached their lowest pH during manufacturing whereas those made in treatments A and E reached their lowest pH during storage and ripening (P<0.01). The soluble nitrogen in treatment A was greater than all other treatments due to higher proteolytic activity. Results from acid degree value revealed that the contribution of lipolysis in such type of cheese was less than proteolysis but mesophilic starters particularly treatment A, gave higher value of lipolysis. The hardness of all cheeses decreased during storage and ripening. Sensory evaluation scores were the highest for starters A and B cheese (P<0.01). Thus, a combination of combination of combination of commercially available mesophilic starters and Lactobacillus casei subsp. casei might be considered appropriate for Iranian white cheese production.

Sixty three barley genotypes including 28 cultivated (Hordeum vulgare L.) and 35 wild (H. spontaneum C. Koch) genotypes collected from a wide geographic area of Iran were compared for salt tolerance. Plants were grown in 2-kg pots and subjected to three salinity (NaCI) treatments [0.97 (control), 9.2 and 17.3 dS m^-1] in a greenhouse, in a factorial experiment with complete randomized design and three replications. During vegetative growth, shoot Na^+, K^+, K^+/Na^+ and proline contents were measured for all genotypes. Plant traits including the plant height, length of spikes, number of spikes per plant, fresh weight and dry matter and grain yield per plant were also measured. There was a very wide variation in salt tolerance of the genotypes with regard to Na^+, K^+/Na^ and proline content. In general, tolerant genotypes with better agronomic performance, contained lower Na^+ and a higher amount of proline compared to non-tolerant ones and these two parameters were significantly and negatively correlated (r=-0.62, P<0.01). Salinity tolerance, tolerance index (ratio of grain yield in saline media to grain yield in non-saline media). Was highly negatively correlated with Na^+ (r=-0.9, P<0.01). Therefore, Na^+ and proline content of the genotypes are two criteria which can be used for indirect selection for tolerant genotypes in bleeding programs.

Water scarcity is considered to be the most important bottleneck in the development of agricultural sector of Iran. Therefore, water-saving technology has recently attracted the government authorities attention. This study investigated the effects of water-saving technologies on cropping pattern and employment in Fars province. The findings indicated that investment in irrigation technology could changes the cropping pattern from less capital and water-intensive to more capital and water-intensive crops. Furthermore, the aggregate area under cropping would increase as a result of water-saving. Adoption of water-saving technology increased employment considerably. The best state of technology for employment in all representative firms was partial investment case. The total number of labor employed in small, medium and large representative farms in this state increased about 56%, 17%, and 103% as compared with state of non-investment in new technology, respectively.

Apples (Malus domestica Borkh. Red Delicious) were vacuum infiltrated (250 mm Hg) for 30 s with 0,1.5, 3 and 6% solutions of calcium chloride (CaCl__2) and stored at 0°C for 6 mo, followed by 1 wk storage at 20°C. Calcium chloride solutions at 3 and 6% concentrations significantly increased fruit firmness tested either immediately after removal from storage or after being held for I wk at 20°C. The correlation coefficient between calcium (Ca) content and fruit firmness (r=75) was highly significant. In another experiment, Red Delicious apples were treated by dip infiltration in 0 and 3% CaC1__2 solution, for 3 min, heat treatment for 4 d at 38°C and dip infiltration (3% CaCl__2) plus heat treatment, before storing at 0°C for 6 mo. Heat treatment and the combination of dip infiltration plus heat treatment significantly increased fruit firmness either immediately after removal from storage or after being held for 1 wk at 20°C.

Annual rainfall and distribution of rain are the major uncontrolled inputs in dryland farming and possibly the main cause of yield fluctuation. Therefore, it is necessary to understand their relationships to the yield of major dryland crops. Furthermore, agroclimatological parameters along with economic analysis can determine the area suitable for dryland farming. The objectives of this study were to seek relationships between seasonal or monthly rainfall distributions and wheat, barley and lentil yields in the southern provinces of I.R. Iran. Monthly rainfall indices excluding January and February were included in multiple regressions for prediction of wheat. barley and lentil yields for the Mamasani, Kazeroon and Sepidan areas. For the Badjgah and Gachsaran areas the regression equations with the seasonal rainfall indices are presented. For the Badjgah area, due to cold winters its indices were excluded while for Gachsaran area (a warm area with shorter growing season) the rainfall indices for all seasons were included in the regression equations. Regions with mean annual rainfall of 300 mm are appropriate for economic wheat dry land farming with 50% probability, ,while areas with mean annual rainfall of 360 mm are appropriate for economic wheat dry land farming with 80% probability. Map of suitable areas for economic dryland farming of wheat with different probabilities are presented.