چكيده لاتين :
Introduction
The practice of growing two or more crops simultaneously in the same field is called intercropping and it is a common feature in traditional farming of small landholders. It provides farmers with a variety of returns from land and labour, often increases the efficiency with which scarce resources are used and reduces the failure risk of a single crop that is susceptible to environmental and economic fluctuation. The most common advantage of intercropping is the production of greater yield on a given piece of land by making more efficient use of the available growth resources using a mixture of crops of different rooting ability, canopy structure, height, and nutrient requirements based on the complementary utilization of growth resources by the component crops. Moreover, intercropping improves soil fertility through biological nitrogen fixation with the use of legumes, increases soil conservation through greater ground cover than sole cropping, and provides better lodging resistance for crops susceptible to lodging than when grown in monoculture. Careful planning is required when selecting the component crops of a mixture, taking into account the environmental conditions of an area and the available crops or varieties. A number of indices such as land equivalent ratio (LER), relative crowding coefficient (RCC), aggressivity (A), competitive ratio (CR), actual yield loss (AYL), and intercropping advantage (IA) have been proposed to describe competition within, economic advantages and equivalent yield of intercropping systems (Agegnehu et al., 2006; Banik et al., 2006; Dhima et al., 2007). The objective of this study was to determine the best treatment of sole or intercropping of wheat and chickpea and evaluation of competition indices in intercropping under nitrogen consumption.
Materials and methods
In order to investigate the competition indices of intercropping of wheat and chickpea under nitrogen effect, an experiment was arranged as factorial based on Randomized Complete Block Design with three replications during 2009-2010 in Gonbad Kavous University farm. Planting patterns factor included four levels of sole cropping of wheat (W), two rows of wheat with one row of chickpea (W2C1), one row of wheat with two rows of chickpea (W1C2) and sole cropping of chickpea (C) and nitrogen application consisted of four levels of 0, 25, 50, 75 and 100 kgN ha-1. Each plot had 5 rows and the rows distance was kept 25 cm in all the treatments. Sowing date was 19th December 2009 and plants harvested at 25th May 2010. Eventually, seed yield and indices of land equivalent ratio, relative crowding coefficient, aggressivity, competitive ratio, actual yield loss, intercropping advantage and barley equivalent yield were computed. Analysis of variance was performed using SAS Software (Ver. 9.1.3) and treatment mean differences were separated by the least significant difference (LSD) test at the 0.05 probability level.
Results and discussion
The results showed that the highest grain yield and wheat equivalent yield was obtained from sole cropping of wheat. In the intercropping of two rows of wheat with one row of chickpea and one row of wheat with two rows of chickpea land equivalent ratio was 0.87 and 0.71 ,respectively, that was less than sole cropping of wheat and chickpea. This means that intercropping requires 13% to 29% more land than the sole crop to produce equal yieldswhich indicating greater land-use efficiency of sole crops than intercrops. relative crowding coefficient of wheat in two rows of wheat with one row of chickpea and one row of wheat with two rows of chickpea was 1.93 and 1.73 and of chickpea was 0.15 and 0.17, respectively. The Aggressivity parameter indicated a tendency for wheat to dominate chickpea in both intercropping. Competitive Ratio in two rows of wheat with one row of chickpea was greater than one row of wheat with two rows of chickpea. Actual yield loss and intercropping advantage in wheat was positive and in chickpea was negative. Intercropping of wheat and chickpea decreased actual yield loss and intercropping advantage. The present study concludes that intercropping of wheat with chickpea in different planting patterns affected seed yield, competition between the two species and economics of the planting patterns as compared to solitary cropping of the same species.
Conclusion
Results of this study illustrated that intercropping of wheat and chickpea was not suitable system. Intercropping indices such as Land Equivalent Ratio, Aggressivity, Competitive Ratio and Intercropping Advantage indicated that wheat crop was the dominant species in two intercropping treatments.
Keywords: Aggressivity, Competitive ratio, Intercropping, Land equivalent ratio, Seed yield
References
Agegnehu, G., Ghizaw, A., and Sinebo, W. 2006. Yield performance and land use efficiency of barley and faba bean mixed cropping Ethiopian highlands. European Journal of Agronomy 25: 202-207.
Banik, P., Midya, A., Sarkar, B.K., and Ghose, S.S. 2006. Wheat and chickpea intercropping systems in an additive experiment: European Journal of Agronomy 24: 325-332.
Dhima, K.V., Lithourgidis, A.A., Vasilakoglou, I.B., and Dordas, C.A. 2007. Competition indices of common vetch and cereal intercropping in two seeding ratio. Field Crops Research 100: 249-256.
