Iranian Journal Pulses Research

Abstract Introduction
Bean is one of the most important legumes worldwide for direct human consumption and it is a rich source of protein and carbohydrates. Bean is weak in competing with weeds due to its slow growth during the early stages. Therefore, competition with weeds causes a significant reduction in grain yield at the end of the growing season. Weeds and crops are always competing for obtaining nutrients, water, light and space. Weed competition is a kind of nonliving stress, which effect on plant yield. The photosynthetic capacity of plants depends on abiotic factors such as the quality and quantity of light. Each of the photosynthetic pigments such as chlorophyll a, b and carotenoids absorb light at a different wave length. The rate of photosynthesis and biomass production in plants is also largely dependent on the chlorophyll content of leaves. The weed interference in the plant growth maybe caused a change in the content of carotenoids and chlorophyll pigments in plant leaves. Pinto bean (Phaseolus vulgaris L.) cultivars, with different morphological and genetic characteristics, show different responses in the presence of weeds, which may ultimately result in possible difference in yield. Measurement of growth indices is necessary to study the competitive ability of species during the growth period.
 
Materials and Methods
In order to investigate the effect of different chemical and non-chemical weed control managements on the yield of determinate and indeterminate bean varieties, an experiment was conducted as factorial based on a randomized complete block design with three replications. This field experiment was carried out in Behshahr, Mazandaran, in 2021. The first factor was different weed control methods: application of trifluralin herbicide as pre-sowing 2.5 liters per hectare; application of trifluralin herbicide 2.5 liters per hectare + one weeding; wheat mulch in the amount of two tons per hectare; application of bentazon 50% of the recommended dose; application of bentazon 75% of the recommended dose; application of bentazon 100% of the recommended dose; weed-free control and control with weed infestation and the second factor includes bean cultivars: Negin variety (determinate growth type) and Sadri variety (indeterminate growth type). Weeds were sampled at flowering and final harvesting stages, and weed species, density, and dry weight of weeds were measured. Also, photosynthetic pigments and yield were investigated.
 
Results and Discussion
The results showed that weed species in the field were from 9 plant families and included 10 species. From the total species observed in the field, 4 species have C₄ photosynthetic pathway, 4 species have C₃ photosynthetic pathway and one species has CAM photosynthetic pathway. The Amaranthus retroflexus L. and Portulaca oleracea L. species had the highest frequency and Chrozophora tinctoria and Physalis alkekengi had the lowest frequency in the field. In all three stages (21 days after planting, flowering and final harvesting stages), the highest density and dry weight of weeds were observed in the control treatment without weeding, and among the weed management treatments, mulch and bentazon 100% treatments caused a decrement in the density and dry weight of weeds in both Negin and Sadri cultivars. Based on the results, the highest chlorophyll a, b and total chlorophyll were observed in both Negin and Sadri cultivars in the weed-free control treatment, and the lowest values were in the control treatment without weeding. Also, the control treatment without weeding had the highest amount of carotenoids in Negin cultivar (0.41 mg.g^-1 fresh weight) and in Sadri cultivar (0.37 mg.g^-1 fresh weight), while the lowest ones in Negin and Sadri cultivar (0.29 and 0.28 mg.g^-1 fresh weight, respectively) was observed in the weed-free control treatment. The highest seed yield of Negin and Sadri cultivar (1957.11 and 2426.01 kg.ha^-1, respectively) were observed in the weed-free control treatment.
 
Conclusions
In general, it can be concluded that the Sadri cultivar with higher competitive ability has performed better against the weed than the Negin cultivar. Among the weed management treatments, the non-chemical management of mulch and the chemical treatment of bentazon 100% had better performance.

Abstract Introduction
The most important principle in the rain-fed cropping system is to maintain and optimal use of soil moisture. In this regard, selecting the appropriate cultivar and planting density is one of the most important management decisions. The open canopy structure, short stature, limited leaf area, and the slow growth rate of chickpea is responsible for its poor competitive ability against weeds. In rain-fed cropping systems, weeds can also play an important role in soil moisture depletion and can aggravate drought stress on crop at the end of the growing season. Among the weed control cropping methods, it is possible to select a competitive cultivar and/or increased planting density. After introducing a new cultivar from rain-fed chickpea, researchers have always compared it with older cultivars in terms of competitive ability against weeds. So far, there has been no comparative study of competitive ability or tolerance of a new rain-fed chickpea cultivar, Adel, against weeds with older cultivars. Consequently, the effect of planting density of this new rain-fed chickpea cultivar on the response of weeds was not investigated. Therefore, the aim of this study was to investigate the interaction of this new and old cultivars and planting density on weeds damage under rain-fed conditions in Kermanshah.
 
Materials and Methods
This research was carried out at the research farm of the faculty of agriculture and natural resources of Razi University, Kermanshah, during 2013-2014 growing season. Wheat was planted in the same farm during the previous growing season. During the experiment, the total rainfall was 85.51 mm. After preparing the land to plots of 6 × 2 m², the chickpea cultivars were manually planted with the distance of 40 cm on each row on 5 February 2013. The experiment was a factorial (3 crop densities × 4 chickpea cultivars × 2 weed interferences) in a completely randomized block design with three replications. Planting densities were 31.3, 38.5, and 50.0 plants m^-2. Chickpea cultivars were Arman (FLIP90-96C), Azad (FLIP93-93C), Adel (FLIP99-66C), and Hashem (FLIP84-48C). The factor of weed interference was at two levels of weeding and unweeding. The crop was harvested on 28 June 2014 to evaluate yield and yield components. The samplings of weeds were performed to determine the total biomass using a 1 m² quadrate on 20 May and 12 June 2014, which were coincident with the flowering time and physiological maturity of chickpea, respectively.
 
 
Results and Discussion
In general, the economic yield was decreased by increasing the plant density in all chickpea cultivars. The planting densities of 38.5 and 50.0 plants m^-2 reduced the economic yield up to 8.9 and 42.6% in Azad cultivar, 30.5 and 37.2% in Arman cultivar, 23.7 and 40.2% in Hashem cultivar and 32.9 and 36.3% in Adel cultivar compared to planting densities of 31.3 plants m^-2, respectively. Azad cultivar produced the highest economic yield (146.4 g m^-2) under weeded condition, while the lowest economic yield (45.2 g m^-2) belonged to Arman cultivar under un-weeded condition. The presence of weeds resulted in a reduction of 59.1, 51.9, 61.2, and 46.3%, in the economic yield of Azad, Arman, Hashem, and Adel cultivars, respectively. During the first weeds sampling, the highest (25.7 g m^-2) and the lowest (17.7 g m^-2) weed biomass were observed at planting density of 31.3 and 38.5 plants m^-2, respectively- whereas during the second weeds sampling, the highest (60.0 g.m^-2) and the lowest (42.8 g. m^-2) weed biomass were observed at 31.3 and 50.0 plants m^-2, respectively. Moreover, during the second sampling of weeds, the highest (54.7 g m^-2) and the lowest (40.8 g m^-2) weed biomass were observed at the plots of Hashem and Adel cultivars, respectively.
 
Conclusion
In this research, the planting density of 31.3 plants m^-2 was optimal planting density for all four chickpea cultivars. It seems that the increase of planting density to control weeds in rain-fed chickpea cropping system is an unsuitable technique. Therefore, it is necessary to consider other techniques to control weeds in rain-fed chickpea cropping systems. An interesting observation in this study was that, although the economic yield of Adel cultivar was lower, the lower biomass of weeds in the plots of this cultivar was observed compared to other cultivars. This observation can be related to allelopathic compounds produced by Adel cultivar which is costly for the crop itself and has reduced its yield.

Abstract Introduction Mungbean [Vigna radiata (L.)Wilczek] is the most important source of protein in south and southeast Asia. This plant, have the most important sources of protein in arid and semiarid regions and played a major role in the economy of the regions. Seed mung bean has 51% carbohydrate, 26% protein, 10% moisture, 4% mineral and 3% vitamin. This crop can be successfully grown on marginal lands where other crops perform poorly. Legumes, have mainly poor competition against weeds. Yield decrease in crops due to the presence of weed, depending on the area and specific weed species its area. Raman & Krishnamoorthy (2005) reported that mungbean yield decreased in infested treatment to weeds to 35 percent. Optimum plant population density is an important factor to realize the potential yields as it directly affects plant growth and development. The sowing rate of 20 kg h^-1 usually recommended for small to medium seed varieties might be too low to obtain optimal yield. Barary et al. (2002) observed the effect of row and plant spacing on seed yield but it was not significant. Among the yield components, number of pods plant^-1 and number of grains pod^-1 and 1000 seed weight decreased with increasing seed rate. Determining the optimum plant density is very important to obtain maximum quantity and quality of economic yield. Reports show that the suitable density range of mung bean depends on the distance between plants. This study was conducted to investigate the effect of density on the morpho-physiologic traits and seed yield of the mung bean and to determine the optimum planting density on weed management in the Khorramabad.   Materials & Methods  Field experiments were conducted at Lorestan Agricultural and Natural Resources Research Center, Khorramabad, Iran (48.36° E, 33.48° N, altitude), 1,125 m above the sea level with annual average precipitation and temperature of 471.5 mm and 17.7 C˚, respectively. The fields were in fallow in the preceding year of the experiments. The soil at the test sites were a clay-silt with a pH of 7.7 and organic matter of 1.0% in 2014. Prato cultivar has a 1000-seed weight of approximately 25 g. Layout system was randomized complete block design (RCBD) with factorial arrangements, with 8 treatments in 3 replications. Weed factor with two levels (controlled and uncontrolled) and seed rate per unit area (25, 50, 75 and 100 kg. h^-1) equivalent (6, 12, 18 and 24 plant m^-2) was calculated for each plot. In this experiment, after sowing mapping, evaluated treatments were randomly assigned to experimental plots and any density considered on the 6 lines with 6 meters length, rows spacing of 60 cm and 5 cm sowing depth. Seeds planting was done by hand in June 12, 2014. Irrigation was done immediately after planting. Due to climatic conditions, farm irrigation was carried out flooding until the end of the growing season (every 10 days). In the plots of interference treatment no operations performed against the weed control. Assessing the density and weeds biomass were randomly at flowering time of crop with samples of the two frame 0.5× 0.5m per plot. Density and dry matter of weeds were counted and measured. At the end of the growing season after physiological maturity with marginal effects deletion (half a meter from the beginning and end of each row) area of 6 m^-2 from 4 central rows of each plot was measured to estimate biomass, yield and seed yield by 14% seed moisture. Determining of morphological traits and yield components was selected 10 plants from each plot at final harvest. The traits measured, including biological and seed yield, plant density, pod number per plant, seed number per plant and seed weight per plant. Analysis was done by analysis variance and by using SAS 9.1. For comparing regression coefficient and latitude of origin two treatments consisting weed free and weed infested in level of seed amount was used.   Results & Discussion The experimental maximum yield (2011 kg. h^-1) was achieved for weed control treatment with crop density of 25 kg. h^-1, while, the lowest yield (672.7 kg. h^-1) was related to weedy plots with crop density of 100 kg. h^-1. The study revealed that crop density of 25 kg. h^-1 mung bean (Vigna radiate) (equivalent to 60 plant. m^-2) is optimum to obtain maximum mung‌ bean yield. Results also indicated mung‌ bean yield increased by 82.7 by weed control, the importance of weed interference in reducing mung‌ bean yield and necessity of weed control to achieve higher yields. Among the yield components, number of pods plant^-1 and number of grains pod^-1 and 1000 seed weight decreased with increasing seeding rate. It seems that seeding rate of 25 kg.h^-1 reduced mung bean density in area unit, and increased weed growth probably due to abundance of resources. However, seed rate of 100 kg. h^-1, the   Conclusion Generally, the results of this research showed that selecting mung bean varieties with runner type and optimum density performance used against weeds can increase competitive pressure. Weeds management by weeding out, not only makes more seed yield but also prevented environmental damage and will help environmental sustainability.