سیدحسام نیک سیرت

Cereals with legume intercropping as one of the ways to increase yield per unit area are recommended. To investigate the effect of cutting off irrigation on yield, yield component and advantageous indices of barley intercropped with legumes, a field experiment was conducted as split plot in randomized complete blocks design with three replicates at College of Agriculture and Natural Resources of Darab, Shiraz University during 2014 growing season. Treatments were included two levels of irrigation regimes as main plot (full irrigation and cutting off irrigation at milk development stage) and cropping treatments consisted of monoculture of Nimroz tow-rowed barley, Zehak six-rowed barley, pea and faba bean and intercropping of Nimroz + pea, Nimroz + faba bean, Zehak + pea and Zehak + faba bean) with a ratio of 1:1 as sub plot. Results showed that under cutting off irrigation number of seeds/spike, harvest index, biological yield and grain yield of barley cultivars decreased 12.5%, 23.6%, 4.3% and 20%, respectively. Under cutting of irrigation at milk development stage, the highest grain yield was obtained in monocropping of Zehak (3470 kg/ha) and Nimroz (3300 kg/ha). After cutting off irrigation at milk development stage, the lowest canopy temperature (28 to 30 ºC) was observed in intercropping treatments. The highest land equivalent ratio (LER) of barley (0.57), legumes (0.83), and total (1.4) were obtained in intercropping of Zehak + pea. In both of the irrigation regimes, Zehak and Nimroz barley cultivars intercropped with faba bean had higher relative value total (RVT) compared to monoculture. In addition, Zehak barley cultivar due to higher grain yield, LER and RVT was better option in intercropping with legumes compared to Nimroz cultivar, under water stress.

A growing interest in intercropping systems has been initiated in developed countries due to the increasing awareness of environmental degradation arising from the heavy use of non-renewable resources such as water. Cereal-legume intercropping are common in natural ecosystems, but now are rarely used in developed countries, except for certain intercropping systems used for animal feed. A renewed interest in intercropping and particularly in intercropping of cereals with legumes has risen again lately. Intercropping can use the available environmental resources more efficiently and thus result in higher yields than monocropping. The reasons for the higher yield in such systems is that the intercropped species do not compete for exactly the same growth resource niche and thereby tend to use the available resources in a complementary way. Izaurralde et al, (1990) used chickpea intercropped with barley in different planting densities and found that grain, straw, and dry matter yields of the mixtures increased with increasing chickpea planting density. With respect to drought stress in late season of Sothern Iran because of cutting off rainfall in this area, and the importance of intercropping to reach stability and sustainability in production, the aim of this study was to assess the changes in yield and yield components of chickpea and faba bean intercropped with barley under late season drought stress. To evaluate the yield and yield components of intercropping chickpea and faba bean with barley cultivars under different irrigation regimes, a field experiment was conducted at College of Agriculture and Natural Resources of Darab, Shiraz University during 2014 growing season. Treatments were included two levels of irrigation regimes (full irrigation and cutting off irrigation at milk development of barley) and 8 cropping treatments consisted of monoculture of Nimroz tow-rowed barley, Zehak six-rowed barley, pea and faba bean and intercropping of Nimroz+pea, Nimroz+faba bean, Zehak+pea and Zehak+faba bean with a ratio of 1:1 which laid out as split plot arrangement in randomized complete block design with three replicates. At crop maturity, plants were hand harvested to measure yield and biological yield and yield components including number of pods/plant, number of seed/plant, and 100-kernel weight. Also, land equivalent ratio (LER) was calculated. LER is the most popular index for expressing the yield advantage of intercropping systems and defined as the relative land area that is required for monocrops to produce the same yields as intercrops. Finally, analysis of variance (ANOWA) was performed using MSTATC ver. 2.1 software (1991) and the means compared by LSD test at 5% probability level. Analysis of variance showed that main effects of irrigation regime and cropping treatments had significant effect on number of pods/plant in chickpea while these treatments had no significant effect on number of pods/plant of faba bean. Under drought stress, number of seeds/plant, 100-kernel weight, grain yield of pea decreased 40, 16, and 57% while in faba bean decreased 32, 18, and 40%, respectively. Interaction effect of irrigation regime and cropping treatment had significant effect on grain yield and harvest index of chickpea and faba bean while this interaction effect had no significant effect on biological yield of two legumes. In chickpea, the highest biological yield (9916 kg/ha) and grain yield (1630 kg/ha) were obtained in monoculture of chickpea and the highest 100-seed weight (25.5 g) and harvest index (%29.85) were obtained in Nimroz+pea intercropping. Also, in faba bean, the highest biological yield (11960 kg/ha) and grain yield (5175 kg/ha) were observed in monoculture of faba bean. Maximum harvest index (%45.58) was obtained in Zehak+faba bean intercropping. Interaction effect of irrigation regime and cropping treatment had significant effect on LERlegumes and LERtotal. Under drought stress, LER in legumes in all of the intercropping treatments increased from 13 to 80%. Likewise, the highest LERcereals (0.57), LERlegumes (0.83), and LERtotal (1.4) was obtained in Zehak+pea intercropping. It is concluded that intercropping of six-rowed Zehak barley cultivar with pea was advantageous system of each legumes in monoculture especially under drought stress condition because of better land use efficiency than sole cropping and the other mixtures. This intercropping system can be adopted by farmers for maximization of yield especially under late season drought stress in Southern Iran.

 

Intercropping is an old and widespread practice used in low input cropping systems in many areas of the world. Intercropping systems, especially those employing cereals with legumes, have several major advantages such as higher total yield and better land use efficiency yield stability of the cropping system, better utilization of light, water, and nutrients. The reasons for the higher yield in such systems is that the intercropped species do not compete exactly for the same growth resource niche and thereby tend to use the available resources in a complementary way. Several indices such as land equivalent ratio (LER), competitive ratio (CR), aggressivity (A), actual yield loss (AYL), and intercropping advantage (IA) have been developed to describe the competition and the economic advantage in intercropping. With respect to drought stress in late season of Sothern Iran and the importance of intercropping to reach stability and sustainability in production, the aim of this study was to assess the changes in yield and competition and economic indices of intercropping barley with legumes under late season drought stress.

A field experiment was conducted to evaluate the competitive and economic indices of intercropping barley cultivars with pea and fababean under different irrigation regimes at College of Agriculture and Natural Resources of Darab, Shiraz University during 2014 growing season. Treatments were included two levels of irrigation regimes (full irrigation and cutting off irrigation at milk development of barley) and 8 cropping treatments consisted of monoculture of Nimroz tow-rowed barley, Zehak six-rowed barley, pea and fababean and intercropping of Nimroz+pea, Nimroz+fababean, Zehak+pea and Zehak+fababean with a ratio of 1:1 which laid out as split plot arrangement in randomized complete block design with three replicates. Competitive and economic indices were including land equivalent ratio (LER), competitive ratio (CR), aggressivity (A), actual yield loss (AYL), intercropping advantage (IA), and system productivity index (SPI). Analysis of the variance was performed using MSTATC ver 2.10 software (1991) and the mean comparisons were performed by LSD test at 5% probability level.

Analysis of variance showed that irrigation regimes and cropping treatments had significant effect on barley and legume yields, LERtotal, Atotal, SPI, CR, AYL total, and IAtotal. Cutting off irrigation, decreased 20, 43 and 40% barley cultivars, pea and fababean yield, respectively and increased 1.9, 42 and 20% LER of cereals, legumes and total, respectively. Also, under cutting of irrigation, intercropping of Zehak+pea had the lowest yield loss (13%) while Zehak+fababean had the highest yield loss (27%) among the intercropping treatments. A and CR indices showed that in full irrigation conditions, barley cultivars were dominant species and at drought stress condition competitive power of legumes increased. In full irrigation, actual yield loss indices of barley cultivars, legumes and total was positive, negative and zero, respectively and intercropping advantage indices of barley cultivar was positive and in legumes and total was negative. Likewise, AYL and IA indices, in cereals, legumes and total were positive. The maximum grain yield in barley cultivars, pea and fababean was obtained at sole cropping treatments, while LER of all intercropping treatments was higher than 1. SPI for all of the intercropping treatments was positive.

Evaluating competitive and economic indices showed that intercropping systems of six-rowed Zehak barley cultivar with pea was advantageous than sole cropping system under drought stress condition because of betterland use efficiency and better economics than the other mixtures examined. This mixture could be economically and environmentally promising in the development of sustainable crop production and thus can be adopted by farmers for maximization of economic yields especially under drought stress condition

Addition of organic residues to soil in organic farming may change soil K status and subsequently its availability and cycling. For this purpose, an experiment was done as factorial in completely randomized design with application of 11 organic materials (alfalfa, barley, pea and broad bean residues and sheep, cow, camel, poultry, pigeon and quail manures and vermicompost) in two clayey soils of Darab and Sepidan (Fars province) under two moisture conditions (field capacity and saturation) with three replicates. First, 2 g of organic materials was added to 100 g of soil samples and incubated for two months under field capacity and saturation conditions and laboratory condition (22±2˚C) and then the contents of soluble, exchangeable and non-exchangeable K were determined. Results indicated that all organic materials, except for vermicompost, alfalfa residue and camel manure increased soluble K and the highest increase was related to sheep manure up to 228 mg kg-1. The content of exchangeable K was increased with all organic residues application from 70 to 730 mg kg-1. The content of non-exchangeable K was also increased with organic residues application and the highest and lowest increases were found for poultry manure and camel manure, respectively. Generally, the contents of soluble and exchangeable K of Darab soil and non-exchangeable K of Sepidan soil were more affected by organic materials application. The saturation condition increased exchangeable K and decreased soluble and non-exchangeable K. Increase in the content of soluble K and soil salinity should be considered for organic amendments application to soils with high leaching potential and for salt sensitive plants.