Modern agriculture largely relies on the extensive application of agrochemicals, including inorganic fertilizers and pesticides Indiscriminate, long-term and over-application of pesticides have severe effects on soil ecology that may lead to alterations in or the erosion of beneficial or plant probiotic soil microflora Weathered soils lose their ability to sustain enhanced production of crops/grains on the same land However, burgeoning concern about environmental pollution and the sustainable use of cropping land have emphasized inculcation of awareness and the wider application of tools, techniques and products that do not pollute the environment at all or have only meager ecological concerns This review covers the types of, concerns about and current issues regarding the extensive application of agrochemicals, in particular pesticides, on a variety of microorganisms integrated in successive food chains in the soil food web

Effect of pesticide application on soil microorganisms

Climate Change, a Challenge for Cool Season Grain Legume Crop Production.- Modelling Climate Change Effects on Legume Crops: Lenmod, a Case Study.- Ecology and Adaptation of Legumes Crops.- Physiological Responses of Grain Legumes to Stress Environments.- Consequences of Predicted Climatic Changes on International Trade in Cool Season Grain Legume Crops.- Impact of Climate Change on Diseases of Cool Season Grain Legume Crops.- Pest Management in Grain Legumes and Climate Change.- Agronomic Approaches to Stress Management.- Major Nutrients Supply in Legume Crops Under Stress Environments.- Salinity and Drought Management in Legume Crops.- Nutrients Use Efficiency in Legume Crops to Climatic Changes.- Water Use Efficiency Under Stress Environments.- Efficient Root System in Legume Crops to Stress Environments.- Weed Suppression in Legume Crops for Stress Management.- Efficient Biological Nitrogen Fixation Under Warming Climates.- Microbes and Agrochemicals to Stress Tolerance.- Integrated Legume Crops Production and Management Technology.- Legumes Cultivars for Stress Environments.- Molecular Biology for Stress Management.- Biodiversity Challenges with Climate Change.- Strategies to Combat the Impact of Climatic Changes.

Climate change and management of cool season grain legume crops

Agrochemicals are the result of modern technology that depends on inorganic fertilizers and pesticides. Over use of these chemicals have severe effects on environment that may lead to an immediate and long term effects. Investigating farmers’ awareness of agrochemicals residues and their behaviors regarding application is important in order to reduce human factors that negatively affect agricultural safety. This study focuses on a summary of both national and international studies regarding the effects of pesticide and chemical fertilizer residues on nature, as well as farmers’ awareness of these effects. This research incorporates the actual performance of farmers of Rupandehi district on the issue of agrochemicals.

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An Overview of Agrochemicals and Their Effects on Environment in Nepal

Effects of pesticides on plant growth promoting traits of Mesorhizobium strain MRC4

The amounts of foliage nitrogen (N) fixed by various annual and perennial legumes growing in Australian pastures range from 250 kg N/ha.year. Differences in N2 fixation result from variations in the proportion of the legume-N derived from atmospheric N2 (%Ndfa) and/or the amount of legume-N accumulated during growth. On-farm surveys of %Ndfa achieved by legumes growing in farmers’ paddocks in Australia indicated that N2 fixation contributed >65% of the legume’s N requirements in three-quarters of the annual legumes examined, but this decreased to two-thirds of lucerne (Medicago sativa; also known as alfalfa), and half of white clover (Trifolium repens) samples. Factors such as low numbers or the poor effectiveness of rhizobial strains in the soil, water stress, high soil concentrations of N, and nutrient disorders contribute to poor nodulation and %Ndfa values <65%, but there is also evidence that the observed %Ndfa can be dependent on the legume species present, and whether the legume is grown in a pure stand or in a mixed sward. The accumulation of legume-N relates primarily to the legume content and net productivity of the pasture. For many legume species, ∼20 kg of shoot-N is fixed on average for every tonne of herbage dry matter produced. Legume productivity can be influenced by (i) sowing and establishment techniques and other strategies that enhance the legume content in pasture swards; (ii) the amelioration of soil constraints; (iii) the use of new legume species (and host–rhizobial strain combinations) that are more tolerant of hostile soil environments than subterranean clover (T. subterraneum) or annual medics (Medicago spp); and (iv) the inclusion of perennials such as lucerne to offset the year-to-year variability in productivity and N2 fixation that is a common occurrence with annual legumes.

https://bioone.org/journals/Crop-and-Pasture-Science/volume-63/issue-9/CP12123/Factors-affecting-the-potential-contributions-of-N2-fixation-by-legumes/10.1071/CP12123.pdf

Factors affecting the potential contributions of N2 fixation by legumes in Australian pasture systems

Sulfonylurea residues have been found to inhibit the growth of some legume crops and pastures in seasons following application. Negative effects of these herbicides on symbiotic nitrogen fixation by legume crops and pastures have been demonstrated. Reductions in nitrogen fixation may result from a direct effect of the herbicide on rhizobial growth and/or an indirect effect on plant growth. In this study the influence of chlorsulfuron on the growth of chickpea rhizobia [Mesorhizobium ciceri (CC1192)], the growth of chickpea plants, and the extent of nodulation and nitrogen fixation by the chickpea/rhizobia symbiosis were examined. In vitro studies (in yeast mannitol broth and a defined medium) showed that chlorsulfuron applied at double the recommended field application rate did not influence the growth of chickpea rhizobia. An experiment using 14C-labelled chlorsulfuron was conducted to determine if rhizobial cells exposed to chlorsulfuron could deliver the herbicide to the point of root infection and nodule formation. Approximately 1% of the herbicide present in the rhizobial growth medium remained with the cell/inoculum material after rinsing with 1/4 strength Ringer’s solution. This was considered unlikely to affect chickpea growth, nodulation, or nitrogen fixation. A pot experiment was used to define the influence of chlorsulfuron on the growth, nodulation, and nitrogen fixation of chickpeas. The presence of chlorsulfuron in the soil reduced the nodulation and nitrogen fixation of the chickpea plants. Pre-exposing rhizobia to chlorsulfuron before inoculating them into pots with germinating chickpea seeds, reduced the number of nodules formed by 51%. Exposure of chickpeas and chickpea rhizobia to chlorsulfuron can adversely affect the formation and activity of symbiotic nitrogen-fixing nodules, even when only the rhizobial inoculant is exposed briefly to the herbicide.

A. Anderson

Papers

Influence of chlorsulfuron on rhizobial growth, nodule formation, and nitrogen fixation with chickpea