Evaluation and Comparison of the Sustainability Level of Agronomy Crops under Drought Condition by Using MCDA in the East of Zayandeh-Rud River Basin

Introduction
Agricultural sustainability is regarded as a key factor for long term profitability of farming in rural areas. Researchers believe that an agricultural system is sustainable if it includes environmental quality, economic viability, and employment and social performance. Agricultural sustainability can be analyzed on diverse spatial scales, from the field to a regional, national or even an international scale. Regarding the natural environment the agro-technical and socio-economic conditions in every region have raised the need for more granular scales of assessment.
A recent drought in Zayandeh-Rud River Basin caused an increase in competition among water users in agriculture, industry, and drinking sectors. There is too much pressure on water resources. This competitiveness can increase agricultural water shortage and serious problems such as agricultural unsustainability.
The availability of water is an important factor for agricultural production in arid and semi-arid areas. Excessive use of water resources influences agricultural development and plays a key  role in environmental degradation. However, evaluation of sustainability under drought condition will be used to help decision makers establish effective water exploitation and allocation policies, and thus facilitate the local agriculture sustainability.
 In this paper to assess agricultural sustainability data are collected by using questionnaire and Expert Choice 11 application in the east of Zayandeh-Rud River Basin.
 The partial goals are including assessment of:

environmental sustainability in case study.
economic sustainability in case study.
social sustainability in case study.
drought impact on crop sustainability in case study.

Material and methods
The Analytic Hierarchy Process (AHP) is one of the most commonly applied MCDA techniques based on value measurement models which proposed by Thomas L. Saaty. This states that transferability of a sustainability evaluation framework is not a strict requirement. Therefore, in this research a set of indicators were used to assess and compare the sustainability level of agronomy and orchard production systems.
Data collection
Data was obtained at the farm by a survey method and applying a structured questionnaire and face to face interviews with farmers in 2013. The questionnaire was divided into three parts consisting, (a) crop management practices, (b) farm structure and economic performance, and (c) individual, household and social characteristics of each farm manager.
Analytical Hierarchy Process (AHP)
AHP was performed by doing five following steps:
Step one: Development an attribute tree. In the attribute tree the agricultural sustainability was primarily divided hierarchically into the tree sustainability pillarsas final goal, then to the lower level criteria, and ultimately to measurable attributes.
Step two:  Pairwise comparison of criteria.
Step three: Pairwise comparison of alternatives (crops) with regard to criteria. At this stage, pairwise comparisons on the alternative crops with respect to the criteria were performed by rating of mean value of indicators. The value of the 22 indicators for each crop and farm was estimated at the farm level.
Step four: Calculating consistency. After each pairwise comparison of the criteria and alternatives, a consistency check must be applied. Priorities make sense if they are derived from consistent matrices.
Step five: Sensitivity analysis. The last step of the AHP is the sensitivity analysis to verify the results of decisions by changing the importance of the criteria. If the priority does not change, the results are robust.
Results and Discussion
Results of this research have indicated that alfalfa with 0.287 preference has a higher level of agricultural sustainability compared to other crops. According to the environmental assessment, barely (with 0.352) were the most sustainable crops. According to the social assessment alfalfa with 0.274 was sustainable crop. According to the results the higher scores are observed in farmers of alfalfa than in other farmers. Alfalfa farmers are highly educated and mainly occupied in off farm activities. In addition, employment rate is much higher in alfalfa. Wheat farmers are younger than other farmers.
According to the economic assessment the alfalfa has significantly higher scores than other crops (utility of about 0.5). The farmers have generally a better farm structure than farmers of other crops. In addition, farm financial indicator values are also much higher in these farms.
Based on performance sensitivity analysis, by changing the weights of the environmental criteria over 0.4, the priorities are reversed and alfalfa is being unsustainable. In this situation, barely is the most sustainable.
Conclusion
In this paper, a methodological approach was presented to assess and compare sustainability of agricultural products at the farm level under drought condition.
According to the environmental assessment, barely was the most sustainable crop. By increasing the use of fertilizer, agricultural sustainability level decreases. The use of fertilizer reflects the specialization and intensification of cropping practices. Barley had the lowest fertilizer usage among other crops. Furthermore, pesticides pose threats to human health and the environment that forage maize and barely have the lowest number of replications of herbicides, insecticides, and fungicides application per growing season. In addition, barely is the most sustainable crop based on water consumption indicator. By decreasing share of agriculture sector from surface water, pressure on groundwater resource increases and agricultural sustainability decreases in drought condition. In this way, sustainability of barely can increase because of low water requirement and resistance to salt.
According to the economic assessment, alfalfa was a sustainable crop. GM for alfalfa was 35 times greater than barely, 14 times greater than wheat and 3 times greater than forage maize. Holding size was larger than other crops for alfalfa that increases yield and may represent potentially higher sustainability efficiency. It is worth nothing that because the smallholders’ farmers break the law of inheritance and land plots to carry out activities by machine and consequently the degree of mechanization is reduced. The multi-partitioning of agricultural lands results in higher yield variability along with more required energy and labor. Wheat and barley were the most sustainable among other crops.
According to the social assessment, alfalfa was sustainable crop. Age has been associated with farmer's education level, attitudes, managerial features, commitment to farming, and size of farming operation. In addition, a farmer's educational level and effective farm management as well as timely adoption of environmentally friendly management practices are positively correlated. Hence, barley and forage maize have respectively higher and lower social sustainability. Furthermore, agricultural employment represents the level of employment in the agricultural sector, illustrating its importance as a source of labor for the rural population. This criterion for alfalfa was 10 times greater than barely, 9.5 times greater than wheat and 6.5 times greater than forage maize. Furthermore, family size indicates that the family members may give significant information about the structure of agricultural household and it highlights the staying of farm population in the countryside.
In the east of Zayandeh-Rud river basin drought along with legal prohibition of land use change were caused to increase migration and decrease income. This can strongly affect the sustainability.
To increase sustainability under drought condition, increasing the efficiency of water use is necessary in agriculture sector in the case of study. But the level of adoption of sprinkler irrigation is low because of: high water PH, high water EC, smallholder’s farmers, and high costs of equipment. Therefore, other methods such as intubation in the field can be recommended for better performance and efficiency of water use and allocation. This requires public accommodations to provide low-interest loans by the government.