Current Approaches To Weed Management

Beans are one of the main and strategic products that stand in the second position after grains. Beans have 20% or 25% protein and 50 to 56% carbohydrate than grains so it has a particular role in nutrient people of underdeveloped Countries and is widely grown as a valuable source of protein. Fertility and weed management are often considered two of the most decretory management factors that greatest menace and impacting crop yield. Weed uses the access humidity, soil productivity, nutrients, providing shelter for Pest - Insect and competes for light and place with crop plants which reasons yield decrease. Nitrogen is the main soil nutrient influencing seed yield and consequence of crop-weed competition. The application of herbicide for weed management, although, is too uneconomical moreover resulting in serious ecological and environmental issues such as an increase in herbicide durability in the weeds, environmental contamination and groundwater pollution.

One of the approaches to management weed in crops is to betterment the ability of the crop itself to dominance weed and fertilization management is an important factor in optimizing crop production and enhancement crop competition potency for weed control. Amplification and extending the role of the organic amendment can decrease the demand for chemical fertilizers and decline contradictory environmental effects. They can play an important role in stabilization atmospheric N and efficiency of plant growth promoting substances. Therefore, in the expansion and achievement of stable agricultural techniques, the organic amendment has great importance in bate environmental pollution and decadence of nature. Chemical fertilizer, Manure, municipal waste compost, and biochar are used in the cultivation of many agricultural crops. Recently, Iranian farmers have shown enthusiastic in application organic amendment to obtain soil nutrients and organic matter. Observation of many researchers indicated Reduction of yield crop and its ingredient with weeds offensive and have shown that decline N dose, organic N sources, convenient fertilization timing and usage methods may favor crop growth at the expense of weeds saberali and mohammadi (2015) showed among all fertilization treatments, seed yield losses were 37% for the low weed density and 67% for the high weed density compared with weed-free conditions, the lowest weed biomass obtained for the application of organic amendments. For the high weed density, seed yield loss due to redroot pigweed competition was 9% more for the application of inorganic fertilizer alone than for the application of organic amendments in the combined and alone forms. They conclude that weed interference in the soybean cropping system can be reduced by using organic amendments as nutrient sources.

Naderi et al (2005) showed that application of organic amendments could increase weed competitive ability. In the first year, urea fertilizer alone and combined with organic amendments led to the greatest rapeseed yield, but in the following year, organic amendments alone were able to increase rapeseed yield approximately equal to urea fertilizer and combined with organic amendments. They resulted in that application of organic amendments alone or combined with N fertilizer could be an efficient method to increase soil productivity.

Blackshaw et al. (2005) showed that the application of fresh and composted manure has the potential to increase winter wheat yield and reduce the growth of some weed species. Menalled et al. (2004) similarly documented that composted swine manure increased the competitive ability of common water hemp (Amaranthus rudis Sauer) - without increasing soybean [Glycine max(L. ) Merr. ] yield. Naderi and ghaderi (2013) have also found that although manure and compost showed valuable potential as an N source and increase corn grain yield, they could also increase the level of weed competition. It is important to expansion comprehensive fertilization strategies for crop production that increase the competitive ability of the crop, minimize weed competition, and decrease the risk of due source pollution from nitrogen; However, less information is available of organic inputs on Red been growth in the presence of competing weeds.

A deeper understanding of which organic amendments affect on weed-crop competitive interactions could help in progress fertilization strategies as a part of integrated weed management.