عنوان مقاله [English]
The relation between agriculture and energy is very tight. Agriculture itself is an energy user and energy supplier in the form of bio-energy. Energy consumption in agriculture has intensified in response to increasing populations, limited supply of arable land and desire for an increasing standard of living. In all societies, these factors have encouraged an increase in energy inputs to maximize yields, minimize labor-intensive practices, or both. Effective use of energy is one of the conditions for sustainable agricultural production, since it provides financial savings, fossil resources preservation and air pollution reduction. In developing countries, agricultural growth is essential to fostering economic development. In Iranian economy, more than 33% of the total population is engaged in agriculture sector. Recent years with the rise in world energy prices the governments has taken steps to reduce fuel and energy consumption. Energy in agricultural sector are divided into two groups of direct and indirect, direct energy is required to perform various tasks related to crop production processes such as land preparation, irrigation, threshing, harvesting and transportation of outputs. Indirect energy consists of the energy used in the manufacture of fertilizers, seeds, herbicides and farm machinery and so on. Recently, application of integrated production methods are recently considered as a means to reduce production costs, to efficiently use human labor and other inputs and to protect the environment.
Material and Methods
This research was carried out to evaluate the effect of conservation agriculture system on energy indices in conventional rotation systems including wheat, barley and cotton. The experiment was conducted at Gonabad Research Station as a moderate climate condition between 2012 and 2016 by using split plot design in a randomized complete block design (CBD) with three replications. Two substantial criteria were investigated such as different tillage methods including conventional plowing, reduction of tillage (Minimum tillage) and direct cultivation (No tillage) as a main plots, as well asamount crop residue involving absence of residues 30 and 60%of the remains as a subplots. The area for each subplot and main plot was 600 and 1800 m2, respectively. In this study, energy indices were calculated using equations .Besides, data analysis and mean comparisons were performed via SAS (SAS, 2002) software and Duncan test, respectively.
Result and Discussion
According to results, electricity, chemical fertilizers and fuel inputs shared the highest energy consumption from the total amount of energy in the conventional crop rotation with 43, 23 and 12%, respectively. On the other hand, the lowest energy consumption related to the input of human resources with an average of 0.7%. In addition, variance evaluation and statistical analysis of energy indices demonstrated that only energy efficiency index for wheat and barley at level (p≤0.05) dramatically affected by tillage methods. . However, the effect of residues and interaction between soil tillage × residues on other energy indices was not significant. Comparison of average values of energy use efficiency index in the conventional rotation illustrated that the highest and lowest values of this index were observed in two methods without soil tillage or direct planting and soil tillage or customary tillage. Therefore, the average of energy use efficiency index for wheat and barley crops in non-tillage method was represented increasing 21 and 9%, respectively, than that of conventional tillage and minimum tillage methods.
Consequently, based on data analysis, it seems that the implementation of conservation agricultural systems with various tillage procedures (non – tillage or minimum tillage) to enhane energy use efficiency is exclusively recommended for wheat and barley agronomic systems in climate condition of this study.