Plant Productions

The role of rice cultivars (Oryza sativa L) and seed rates in integrated weed management under direct-seeded rice conditions in Khuzestan province

amir ali kavand; ahmad zare; amin lotfi jalal- abadi

Articles in Press, Accepted Manuscript, Available Online from 02 March 2025

https://doi.org/10.22055/ppd.2025.48523.2240

Abstract

Abstract Introduction A significant portion of rice cultivation methods worldwide is conducted through direct seeded rice (DSR) due to labor shortages and the need to conserve water ... Read More Abstract Introduction A significant portion of rice cultivation methods worldwide is conducted through direct seeded rice (DSR) due to labor shortages and the need to conserve water or lack of sufficient water access. One of the disadvantages of direct seeded rice method is severe weed infestation, which, if not controlled, can lead to a significant reduction in yield. Therefore, the use of various methods, especially cultural methods alongside chemical methods, can be effective in integrated weed management. Materials and methods An experiment was conducted based on a factorial design within a completely randomized block design (RCBD) with three replications in 2022 growing season in the Mianab region Shush, Iran. The first factor included four seed rates (90, 120, 150, and 180 kg ha-1), the second factor included three rice cultivars (Anbarboo, Shiroodi, and Zeighami), and the herbicide treatment (application of bispyribac-sodium herbicide and no herbicide application). Dry weight of jungle-rice (Echinochloa colona (L.) Link) and Bearded Sprangletop Leptochloa fusca (L.) Kunth), the number of grains per panicle, the percentage of empty grains and grain yield were calculated and analyzed. Result and Discussion: The results of the mean comparison of the interaction effects of seed rates and different rice cultivars indicated that the highest dry weight of jungle-rice (78.5 g•m⁻²) was related to the 90 kg ha-1 seed rate treatment in the Anbarboo cultivar and the lowest (12.26 g•m⁻²) was related to the Zeighami cultivar under the 180 kg ha-1 seed rate conditions. The percentage reduction in dry weight of jungle-rice in the Anbarboo, Shiroodi, and Zeighami cultivars, when treated with a seed rate of 180 kg ha-1 compared to a seed rate of 90 kg ha-1, was 60%, 65%, and 82%, respectively. Additionally, the interaction effects of seed rates and herbicide treatments revealed that under both herbicide application and non-application conditions, the highest dry weight of jungle-rice (22 and 124 g•m⁻²) was observed at the 90 kg ha-1 seed rate and the lowest (3 and 41 g•m⁻²) at 180 kg ha-1 respectively. The results showed that bispyribac-sodium herbicide was not successful in controlling Bearded Sprangletop, and the dry weight of this weed significantly decreased with increasing seed rate. The number of grains per panicle in the Shiroodi and Zeighami cultivars was higher in the 120 and 150 kg ha-1 seed rate treatments compared to the 180 kg ha-1 treatment. The interaction effects of cultivars and herbicide treatments also showed that the highest number of grains per panicle was related to the Shiroodi cultivar under herbicide application conditions (80 grains per panicle). At lower seed rates (90 kg ha-1), due to increased weed competition, and at the seed rate of 180 kg/ha, due to increased intraspecific competition, the percentage of empty grain increased compared to seed rates of 120 and 150 kg ha-1. The percentage reduction in empty grain at the seed rate of 150 kg ha-1 in the Anbarboo and Zeighami cultivars compared to the seed rate of 90 kg ha-1 was 38% and 27%, respectively. The results of the interaction between seed rate and different rice cultivars showed that the highest grain yield (4194 and 4119 kg ha-1) was related to the Shiroodi cultivar at seed rates of 150 and 180 kg ha-1, respectively. In contrast, the lowest grain yield (1468 kg ha-1) was observed in the Zeighami cultivar at a seed rate of 90 kg ha-1. Conclusion Therefore, based on the results, the optimal treatment was the application of the Shiroodi cultivar with a seed rate of 120 to 150 kg ha-1 under herbicide application conditions.

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Yield gap analysis of rice in Shoaybiyeh, Khuzestan: yield-reducing factors have the greatest contribution to grain yield reduction

Ghazban Anafjeh; Elham Elahifard; Abolfazl Derakhshan; Ahmad Zare

Volume 47, Issue 3 , November 2024, , Pages 425-440

https://doi.org/10.22055/ppd.2024.46453.2153

Abstract

Introduction One of the main issues of crop production in Iran and many countries of the world is the difference between the farmers’ yields (actual yield) and the achievable ... Read More Introduction One of the main issues of crop production in Iran and many countries of the world is the difference between the farmers’ yields (actual yield) and the achievable yields (potential yield). This distance and yield difference is named the yield gap. Therefore, research was conducted with the aim of determining the rice yield gap in Shoaybiyeh region of Khuzestan province. Materials and Methods This research was conducted in 2020 growing season as a survey in 100 rice fields in Shoaybiyeh region of Shushtar county. Comparative performance analysis method was used to determine rice grain yield gap. The modeling of grain production in rice fields was done by examining the relationship between all the investigated variables with the grain yield observed in the fields using progressive stepwise regression method. The production model obtained with this method was able to justify 89% of the grain yield changes of the studied rice fields with the studied variables. Results and Discussion The results showed that there was a gap of about 1495 kg ha-1 between the average yield of farmers (5044.47 kg ha-1) and the achievable yields in the region (6902.61 kg ha-1). From this value of the expected yield gap in the region, the contribution of factors such as the age of the farmer, the intensity of the weed infestation in the fields, the presence of weed in the fields, the use of adjuvants during the spraying operation, the intensity of the infestation of the field with the striped rice stemborer, and the intensity of the infestation of the fields with the blast disease were equivalent to 3.29, 62.29, 2.53, 6.99, 20.22 and 4.68%, respectively. The analysis of rice yield gap showed that the weed infestation of the fields alone accounted for about 62.3% of the yield reduction compared to the achievable yields. In all the studied fields, the weeds of purple nutsedge, junglerice, broadleaf cattail, and johnsongrass were observed and recorded. Due to the lack of diversity in the fields, the model was not able to distinguish the amount of yield loss caused by these weeds. Intensity of weed contamination of rice fields was also observed in only 6% of the fields, and in the remaining 94%, moderate to very high contamination was observed. Some used herbicides such as bensulfuron-methyl and tribenuron-methyl showed a significant negative relationship with grain yields observed in rice fields. Therefore, it seems that farmers should reconsider the use of these herbicides in rice fields. Also, the delay in sowing and laxuary consumption of nitrogenous fertilizers was closely related to the severity of weed infestation and yield reduction. Investigating the relationship between the yields obtained in rice fields and the date of herbicide spraying (31 to 77 days after planting), a significant negative relationship was clearly observed; That is, with the delay in the spraying time and the consequent increase in the competitive ability of weeds, which may be associated with the decrease in the effectiveness of herbicides, yield have decreased linearly. Conclusion In general, among the variables that had a significant impact on the observed yields in the region, except for the age variable of the farmer, all of them were related to yield-reducing factors, including pests, diseases, and weeds. Based on the results, the yield reducing factors, explained about 90% of the yield gap observed in the region.

Evaluation of periods of interference and weeds control in chemical and organic nutrition management on yield and yield components of garlic

Reza Zahedipour; Aydin Khodaei Joghan; Ahmad Zare

Volume 46, Issue 1 , June 2023, , Pages 105-115

https://doi.org/10.22055/ppd.2022.40244.2017

Abstract

IntroductionGarlic (Allium sativum L.) as one of the medicinal plants has an important role in human health. Weeds control is very important to achieve optimal yield in agro-ecosystems. ... Read More IntroductionGarlic (Allium sativum L.) as one of the medicinal plants has an important role in human health. Weeds control is very important to achieve optimal yield in agro-ecosystems. The competitive ability relationship between plant and weeds is determined by the species' biological traits and environmental conditions such as space, light, water, and nutrient availabilities. Fertilizers play a significant role in the competition between crops and weeds in agriculture. Responses of weeds and crops to fertilizer application could be different, but many weeds tend to respond better than crop species to the high availability of nutrients. Also, the kind of fertilizer (chemical and organic) can affect crop-weed competition. Therefore, the purpose of this research was to evaluate interference and weeds control periods in the application of chemical and organic fertilizers on the yield and yield components of garlic in Ramhormoz climate. Materials and MethodsA factorial experiment based on randomized complete block design (RCBD) with three replications was carried out in Ramhormoz during 2019—2020 growing season. The first factor included nutritional management (chemical and organic) and the second factor included 12 treatments of interference and control period of weeds (0, 20, 40, 60, 80, 120 and 160 days). Chemical nutrition management includes the application of urea (46% application preplanting and after emergence) and Triple superphosphate (46% application preplanting) and Organic management, including the application of cattle compost and inoculation with Mycorrhiza. Results and DiscussionThe results of analysis of variance revealed that the effect of nutritional management on height of garlic wasn’t significant and on other traits garlic (Bulb diameter, bulb weight, Number of cloves per bulb, Biological yield and yield bulb) and weeds (narrow leaf dry biomass, Broad leaves dry biomass and Total weeds dry biomass) was significant. Periods of Weed Interference and Control weed treatments on all measured traits of garlic and weeds were significant. No interaction effects of nutrition and weed management treatments on the studied traits were observed. There was a significant difference between chemical and organic nutrition management, most of the yield traits and yield components of garlic were higher in organic application than chemical fertilizers. Also, the narrow leaf biomass, broadleaf, and total weeds in chemical application in comparison to organic fertilizers increased by 11.5%, 9%, and 10.5%, respectively. During the interval period for 120 days, garlic yield decreased by 100% and with the increase of control period (control in all growing seasons), bulb yield reached the highest value (3230 g.m-2). In weed control treatment for 20 days, bulb yield decreased by more than 86% compared to weed control treatment throughout the growing season. It seems that organic fertilizers with gradual release of nutrients could affect the competition of garlic with weeds, and by using organic fertilizers, the dry weight of weeds was less than chemical fertilizers. ConclusionThe results indicated that due to the presence of weeds and the poor competitive ability of garlic against weeds, the field must be controlled for a long time and the use of manure fertilizer for organic agriculture and increasing soil organic matter is recommended.

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Author = zare, ahmad

The role of rice cultivars (Oryza sativa L) and seed rates in integrated weed management under direct-seeded rice conditions in Khuzestan province

Abstract

Yield gap analysis of rice in Shoaybiyeh, Khuzestan: yield-reducing factors have the greatest contribution to grain yield reduction

Abstract

Evaluation of periods of interference and weeds control in chemical and organic nutrition management on yield and yield components of garlic

Abstract