Experimental Alternate Wheat - Legume Cultures  in the Same Year with Nitrogen Fertilizer Saving Effect

Project location: ITALY
Project start date: February 2011 - Project end date: February 2012
Project number: 2010-44
Beneficiary: ISPA - CNR

One of the objectives and targets of the project is to preserve the soil used for crops destined to human consumption thanks to the development of novel practices of alternate cultivation of legumes to replenish and optimize the soil nitrogen before a new wheat crop.
The project will investigate the saving achieved through nitrogen fixation, analysing the fertilizer required for growing the subsequent wheat crop cycles, incorporating biological nitrogen fixation into the bioenergy cycle. The project will compare the crop yields in two successive years, evaluating the amount of wheat grains produced in the presence of a reduced use of fertilizers supported by nitrogen enrichment of natural source (nitrogen fixing rhizobia).

Legume-supported rotations are used in many countries such as China and India, and have returned to the forefront in Canada and Australia. Rotation of soil use is an optimum practice to reintroduce nitrogen without using costly chemical fertilizers. However rotations have only been studied for soybeans and this will be a pilot study using chickpeas. Grain legume crops are usually incorporated into crop rotations every 3-6 years in a limited zone of central Europe, and the present experiments extend to all the pedoclimatic zones of Europe. The existence of many benefits of legumes to the cropping system, however, suggests that some of the benefits are either not known to or not valued by the grower. Life Cycle Analysis has, on a limited scale, already helped to breach this gap and now needs to be extended into many more regions of Europe, to put monetary values on some of the otherwise unvalued benefits of legume-supported cropping. Since legume cultivation may help mitigate greenhouse gas emissions, the cost and effectiveness need to be determined and put into the context offered by other measures. This may have great influence on Climate change policies, global warming policies, in order to decrease CO2 levels (thematic of Environmental conservation Europe).
As the world's population edges ever closer to the United Nations' forecast of 9 billion by 2050, and as climate change alters land use patterns, farmers will be expected to produce more than ever before from the limited stock of agricultural land. Yet, productive agriculture depends on healthy ecosystems. Without fertile soils, intact water catchments, pollinator species, and natural controls over pest and disease, more food cannot be produced economically or sustainably.
Europe imports about 70% of its plant-derived protein, including 21-30 Mt soybean meal annually between 2000 and 2005 (FAOstat data). Legumes occupy only 2-2.5% of European arable area, less than a quarter of that in comparable agricultural systems. Increasing the grain legume area 4-fold, at current European average grain legume yields of 2.0-2.2 t/ha, would substitute for 50% of soybean meal imports. The heavy dependency of European agriculture on synthetic nitrogen fertilizer demands high energy inputs and causes outputs of greenhouse gases (GHG) and water-polluting runoff. The biological nitrogen fixation of legume crops is a vital way of minimizing the environmental impact of agriculture, especially its contribution to climate change. Increased use of legumes will also assist with diversifying both farm income and landscapes, while improving soil health and decreasing cereal crop diseases, thus adding to the overall health and well-being of the agricultural and rural environments. Growers often treat legumes as "just" a break crop, and sometimes a source of "free" nitrogen, but the crops have many effects on soils, subsequent crops and the surrounding environment.
A remarkably strange observation is how few bioenergy crop scientists consider these implications. In a recent session on bioenergy cropping at the Biomass for Bioenergy meeting in September 2009 most of the reports talked about leaving out nitrogen sources biofuels are considered an attractive alternative to fossil fuels for meeting future global energy demands. The production of chickpea has twofold benefit for the population. At first, there is an increase in a staple food, in second instance there is a by-product, the chickpea pods, that sustain the livestock feedstuff economy and the waste economy, through bio-based biotechnologies (production of bioethanol, buthanol, organic acids, etc...). This is a necessary attainment to the environment protection regulations, in agreement with the Kyoto protocol on the necessity to reduce CO2 levels in the near future. In first instance, legumes can be used for human use or as feedstock, in second instance the plant by-products (polysaccharides and fibres) can be used to produce bio-based compounds and bioethanol. Lastly, the growth of a crop translates in a decrease of CO2 balance and lower free CO2 levels.
It was estimated that in 30 years the growth of trees in lands destined to reforestation may adsorb an amount of CO2 from 6 to 9 fold higher than that saved using biodiesel produced from crops in similar field extension sizes (data from the World Land Trust). Cultivated crops has a lower impact on CO2 balance, since they are annual so that influence to a lesser extent the GHG cycle, however plants absorb and are a good sink of carbon dioxide.

Annual in field rotation of cultures cycling wheat and chickpea (with nodule -fixing rhizobia) for nitrogen enrichment: in this work, chickpea varieties selected by ICRISAT for drought tolerance will be used in association with several nitrogen-fixing Rhizobium strains to enrich the soil during the autumn season to prepare the soil to the winter wheat cultivation.
The project will investigate the saving achieved through nitrogen fixation, analysing the fertilizer required for growing the subsequent wheat crop cycles, incorporating biological nitrogen fixation into the bioenergy cycle.

The environment will benefit by this approach for the low impact of the cultivation methods, fewer fertilizers will be used with containment of reagents, with decrease of wastes (less water pollution). Farming will benefits by reduced emissions of nutrients, chemicals and/or CO2, sustained development of rural areas, and regeneration of soils.
Project outputs: Agronomic aspects of legume-supported cropping systems and cultivation practices and farming systems, and socioeconomic analyses of legume-supported agriculture Legumes are widely seen as critical is in supporting sustainable energy cropping, where the aim is to minimize greenhouse gas release and energy consumption, both of which are critically affected by synthetic nitrogen fertilizer.
 


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