bhagirath singh chauhan

The different species of Amaranthus species are among the most important damaging weeds in the world. Due to the importance of studying the effect of management factors on seed dynamics of different weed species, this experiment aimed to investigate the effect of burial depth and high temperatures on the seed dynamic of different species of Amaranthus in Golestan province including white pigweed (A. albus), prostrate pigweed (A. belitoides), hybrid Amaranthus (A. chlorostachys), redroot pigweed (A. retrofelexus) and green Amaranthus (A. viridis) were performed.

This research was conducted on five amaranthus species of white pigweed, prostrate pigweed, hybrid Amaranthus, redroot pigweed, and green Amaranthus at the seed laboratory and greenhouse of Gorgan University of Agricultural Sciences and Natural Resources. In the first experiment, seed emergence of different species of Amaranthus was studied in eight burial depths including 0, 1, 2, 3, 4, 5, 7, and 10 cm. In the second experiment, seeds were exposed to 50, 60, 70, 80, 90, 100, and 110 °C temperatures for 5, 10, and 15 minutes

All seeds of A. blitoides and A. viridis germinated in the topsoil (zero depth); But, in A. albus, A. retroflexus, A. chlorostachys, 93%, 83%, and 3% of the seeds were emergence at the soil surface, respectively. By increasing the burial depth to one centimeter, the percentage of seeds emergence in different species of Amaranthus decreased significantly and was negligible at ≥ 2 cm depth. Germination test performed on retrieved seeds showed that zero to 16% of the seeds were able to germinate in petri dish, and most of the non-germinated seeds were viable. In all species except for A. chlorostachys high temperatures reduced the germination percentage.

Due to the reduction of seed germination percentage of different species of Amaranthus from a depth of more than one centimeter of soil, it seems that the use of conservation and conventional tillage methods has a good potential to reduce infestation of fields by these weeds. Also, although high temperatures reduce weed infestation in fields, they do not have a significant effect on depleting the seed bank of these species.

Highlights:

1- Seed dynamics of different species of Amaranthus were affected by burial depth and high temperature
2- Deep burial of seeds of different species of Amaranthus causes the stability of their seeds in the soil seed bank.

Herbicides have increasingly become a key component on crop production system because they offer the easiest, cheapest and timely weed management, resulting in higher yield and profit. A single herbicide application in field conditions in most of the cases is not enough to control diverse weed flora. In such situations, tank mixtures of herbicides may provide a prime option to control a broad spectrum of weeds. Cyperus rotundus L., a world’s most tenacious weed, is becoming a problematic weed in conservation crop production systems. A two-year study (2013/14 and 2014/15) was established in South-West Bangladesh to evaluate the effect of application timings and sole and tank mixtures of 2,4-D and ethoxysulfuron herbicides on weed suppression and performance of wheat. 2,4-D and ethoxysulfuron were applied solely and as tank mixtures at 10, 20, and 30 days after sowing (DAS) and these treatments were compared with completely weedy and weed-free treatments. In controlling weeds, tank mixtures of 2,4-D and ethoxysulfuron performed better than their sole application at any application timing; however, at the earliest time (10 DAS), the combination created toxicity to wheat plants, resulting in 10-22% and 11-32% less wheat plant density and biomass, respectively, compared with their sole application. Tank-mix herbicides reduced C. rotundus biomass by 87-91%, 88-100%, and 79-80% when applied at 10, 20, and 30 DAS, respectively, compared with the weedy plots. The plots applied with tank mixtures at 20 and 30 DAS produced wheat grain yield similar to that of weed-free plots, indicating that the tank mixture of 2,4-D plus ethoxysulfuron herbicides is the best option to control weeds without any toxicity to wheat plants.

Genus Salsola, a genus of annual semi-dwarf to dwarf shrubs and woody tree species, is widely distributed across the arid and semi-arid areas of the world. Several features like high fodder value, abundant seed production, tolerance to extreme climatic conditions like high temperature and prolonged drought conditions contributed significantly towards its success as a potential forage species in semi-arid to arid environments. Species of this genus are of significant importance and species like Salsola soda are cultivated and consumed as vegetables in Italy, while others (S. tragus and S. baryosoma) are utilized as livestock fodder in arid and dry areas. The species of genus Salsola are grouped as halophytes, which are also useful for rehabilitation and reclamation of degraded saline lands and saline soils, respectively. Many plants of this genus are used in medicines and cosmetics as they are cure for human heart, skin diseases, cough and influenza. This paper comprises a comprehensive review on the important species of Salsola, along with its medicinal uses and other useful properties that will aid the researcher in determining the need of future research. We focus on the adaptive features of genus Salsola plants for their effective utilization in drought prone semi-arid to arid conditions and also to remediate degraded saline soils.