Dear Babu Meena,

Please go through the attached article.

Good luck

 Thank yo so much Dr. A Singh for  providing good attachment article

Green manuring with legumes can provide all the nitrogen needed in cropping system. To do this you will need to intensively grow the legume green manure of the appropriate species and varieties. Maize is a crop that needs high requirement of nitrogen to perform optimally. Under North American conditions red clover does not provide sufficient nitrogen for the follow crop of maize however alfalfa and hairy vetch do. Ideally, a perennial ley can be used to precede a cropping period of row crops. In a mixed plant and animal system the animal manures are used for compost and returned to the cropping system. Perennial use of legumes optimize animal nutrition and also improved soil fertility maximally. In addition to cover crop, legume focus, mixed animal farming, return of manures as compost there is also a need to develop soil conservation to control losses from erosion and analyze soil for needs related to soil balancing. Farmers extensionists and researchers also need to check for soil profile constraints such as physical limitation from clay layers and beware of acidity salts and other concerns.. 

Yes green manure have very long history of sustaining soil health as well as crop productivity on a long term basis , in addition to moderating climate change impact. CA is one such approach where green manure crops and cover crops are almost a thumb rule..

While the emphasis is given in green manure to its nutritional effect there are other effects which can be impactful. One of the biggest impacts of agriculture is weed management. Green manure can be critical weed management and play a critical role for increasing yield and quality from the control plant disease and pests. The use of cover crop can use the cover to substitute for chemical fumigation. While chemical fumigation can cost hundreds of USD per hectare the use of biofumigant covers can be effective at a much lower cost. Rather than having a toxic legacy the cover crop can leave an improved soil. In addition, the use of cover crops combines well with reduced and no-till agriculture.  Cover crops are most effective as part of systematic agriculture with concrete goals for soil improvement. 

Unfortunately in lust towards clean cultivation or  mechanised farming , we have comprehensively forgotten the utility of cover crops  or green manuring crops , how much such practices add to the soil health and corp production sustainability , either in shorter term or in the longer run...

Alternate sources to supplement inorganic fertilizers are green manuring and are low cost and effective technology in minimising cost of fertilizers and safeguarding productivity. Green manure crops are grown for the purpose of restoring or increasing the organic matter content in the soil 

 So they will increase nutrient availability for sustaining crop productivity.

I think yes. The legumes have the possibility to fix nitrogen from the air and then increse soil fertility after using a part for their growth. But their are some legumes which do not fix more than their needs, such as groundnut, Senna siamea. These legumes can not increase soil fertility by the nitrogen fixed. But they can nevertheless contribute to crop productivity if they produce a great quantity of green manuring. That's the case of Senna siamea, a tree, with action on soil quality improvement by its roots, and also a great quantity of green manuring. The importance of S. siamea is approximaly that of agroforestry. 

Dear Mr. @Babu Meena See this work done here in Brazil, follow the link:

http://www.agencia.cnptia.embrapa.br/Repositorio/Adubacao_verde_e_fixacao_biologicaID-1mmPOcUwAn.pdf

See this work in Colombian acid soils: Effects of cover crops or green manures in weed mangement and soil health. 

http://www.scielo.org.co/pdf/agc/v27n2/v27n2a11.pdf

Mucuna is outstanding for its ability to combine it's high nitrogen fixation, with high biomass production, and allelopathic suppression of major weed species. It also has great ability to increase soil carbon in a relatively short period. Used as intercrop it can sustain a corn after corn crop rotation while simultaneously increasing soil quality and crop yield. Amazing. 

Investigation carbon residence time in soil through green maturing would be an exciting option.And, enriching the labile pool of soil SOC  through combination green maturing plus  biochar will further expa d the soil non- labile pool of soil SOC..

Especially nitrogen

Yes, green manuring with legume besides improving nutrient availability will also improve soil physical and biological health

Another good side effect of green maturing is the utmost control on weeds ...besides improvement in soil physico-chemical and biological properties..

Undoubtedly legume green manuring increase the nutrient availability especially N, improving soil health, besides reducing weed population in succeeding crop.

Yes green manure have very long history of sustaining soil health as well as crop productivity on a long term basis , like intercrop, but is not sufficient. You need aplied fertilizer.

If the extra care is given the cover crop the cash crop then is much easier to manage. This is one of the big secrets of organic farming is work up front to maximize the cover crop and that will minimize the issues on the back end with the cash crop. The organic farmer like the chess master needs to think several moves ahead to get maximum advantage. 

Yes absolutly its can. Many research prove it. The functions of green legume are fixation free nitrogen and help soil aeration be better. Another function is controlled the weed but the legume must be controlled because its can dominated the area and make hard competition with the main plant

I feel, it  is the entire nutrient pool of the soil subjected to green manuring ,  which could find an unprecedented fillip vis-a-vis crop response . however , in order to hasten the crop response , addition of nitrogen  could further mineralise the tagged nitrogen ..this is the reason , green manuring is considered so comprehensive in magnitude of  crop response on a variety of soil types

Good points Dr. Anoop, green manuring helps greatly in improving soil physico-chemical and biological properties. 

Yes. Generally, legume green manuring, such as Mucuna pruriens, Aechynomene histrix, Cajanus cajan, and Senna siamea increase nutrient availability for crop productivity. This is done through their biomass humification and a part of the nitrogen fixed from the air. A legume like Senna siamea (a tree) improves also soil fertility through the its roots action. The legumes fix nitrogen from the air, use one part from their own groth and introduce the second part into the soil for other crops nutrition. But, we have also legumes which do not increase nutrient for crops, because their nitrogen fixed  from the air is lower than their need. That's the case of groundnut. 

In addition to these changes, there would be much higher  rhizosphere microbial diversity  as well, which is so very important to sustain a cropping sequebce and the agroecosystem both.

Up to 20% of all photosynthate is exuded as root secretions. Legumes can optimize the cropping system by its ability to combine with rhizobia to give more optimized nitrogen in the soil as a final destination. The stabilized soil organic matter is optimized under conditions which are not nitrogen limited or constrained and decay rates do not exceed the generation rate. Stabilized organic matter is rich in both Carbon and Nitrogen. Without optimized Carbon Nitrogen the water and nutrition needed by plants will be compromised. The microbial communities in soil and rhizospheres are enhanced under legumes and earthworms can be 3 to 4 times more frequent under clover rather than grass. The legume pigeon pea has marked ability to adapt to a wide range of soil environments and this is related to 3 mechanisms 1) biological nitrogen fixation, 2) mycorrhizal root extension and 3) the production of organic acids which mobilize the scarce amounts of phosphorus. Nitrogen fixation is optimized when P can be mobilized for legume production.  These characters are related to broad adaptability under even difficult soil conditions. The ability of pigeon not only supplies all the N requirement for the pigeon pea itself but provides sufficient N for succeeding crops and the soil itself. As a proponent of Mucuna I see its ability to be intercropped with maize controlling problematic weeds and contributing to massive improvement of soil organic matter simultaneously contributing to its common name as fertilizer bean in Central America. This ability is related to large biomass and its nature and quality of resistant metabolites. A velvet bean is known for its extraordinary amounts of levo dopa. When a velvetbean is wounded the levo dopamine bleeds becoming red as it is transformed to red dopachrome which then polymerizes into black melanin. Before ones eyes extraordinary.  The ability of melanin to show resistance in its carbon and impart the rich blackness. Indeed this coincides with the ability of this plant to accumulate carbon material in the soil itself. Many researchers stress than resistant lignin and melanin are likely involved in resistant carbon resource which accumulates in soil as persistent carbon.  

Must Read work below....

Please find an interesting work..entitled Carbon sequestration in agricultural soils via cultivation of cover crops – A meta-analysis (Agriculture, Ecosystems and Environment 200 (2015) 33–41)

Abstract;A promising option to sequester carbon in agricultural soils is the inclusion of cover crops in cropping systems. The advantage of cover crops as compared to other management practices that increase soil organic carbon (SOC) is that they neither cause a decline in yields, like extensification, nor carbon losses in other systems, like organic manure applications may do. However, the effect of cover crop green manuring on SOC stocks is widely overlooked. We therefore conducted a meta-analysis to derive a carbon response function describing SOC stock changes as a function of time. Data from 139 plots at 37 different sites were compiled. In total, the cover crop treatments had a significantly higher SOC stock than the reference croplands. The time since introduction of cover crops in crop rotations was linearly correlated with SOC stock change (R2 = 0.19) with an annual change rate of 0.32 0.08 Mg ha1 yr1 in a mean soil depth of 22 cm and during the observed period of up to 54 years. Elevation above sea level of the plot and sampling depth could be used as explanatory variables to improve the model fit. Assuming that the observed linear SOC accumulation would not proceed indefinitely, we modeled the average SOC stock change with the carbon turnover model RothC. The predicted new steady state was reached after 155 years of cover crop cultivation with a total mean SOC stock accumulation of 16.7 1.5 Mg ha1 for a soil depth of 22 cm. Thus, the C input driven SOC sequestration with the introduction of cover crops

proved to be highly efficient. We estimated a potential global SOC sequestration of 0.12 0.03 Pg C yr1, which would compensate for 8% of the direct annual greenhouse gas emissions from agriculture. However, altered N2O emissions and albedo due to cover crop cultivation have not been taken into account here. Data on those processes, which are most likely species-specific, would be needed for reliable greenhouse gas budgets.PDF enclosed for further reading..

One of the top soil generating natural ecosystems is the prairie. Prairies are characterized by a broad range of diverse herbs and grasses with major accumulation of roots which penetrate deep in the soil. In addition, this ecosystem has the dominance of perennial species. This ecosystem supports large ruminant herbivores which play keep roles through the recycling of their wastes and their roles to stimulate grass and herb growth. Another aspect is that the biomass from such systems is periodically regenerated by wild fires. The importance of this system is that it points to elements which produce the maximized soils. All over the world, the best soils have always developed on top of natural prairies. Throughout our geological history, the areas of these prairies are where top soils are generated can serve us today as a model system. Prairie soils can have top soils up to several meters depth and represent a massive vault where carbon and nitrogen can be stored to reverse its presence in the atmosphere as greenhouse gas.  The cover crop ability to regenerate soil is significant but small compared to mixed cropping and livestock systems which are aimed at carbon sequestration. Indeed while these cover crop approaches can yield an increase of Carbon up to 1000 kg C per ha per annum the use of holistic grazing can result in much higher rates. Rattan Lal suggested no-till could counteract about 10% of the greenhouse gas emissions and Puget and Lal calculate no-till can contribute about 300 kg/ha/year carbon sequestration for long term no till experimentation on clay loam soil in Ohio. From Rodale work, the University of California and USDA Maryland, the cover crop can produce 2 to 4 times this amount from conventional no-till without cover crops.. The employment of state of the art mixed farming can multiple this cover crop amount similarly up to 2 to 4 times the cover crop amount and finally these mimic the prairie system dynamics. If we add the regeneration of ecosystem by periodic burning the method of bio charring represents a real practice which can completely remediate the greenhouse gas issue if applied to its potential. In reality, we need to work on emission reduction and land sequestration but the big tool in our toolbox for improving our land environment energy and address climate change drivers is the transformation of our agricultural using the concepts found in the global prairies. 

Generally, legume green manuring, such as kUDSU LIKE A COVER CROPS IN OIL PALM PLANTATION IN ecuador FIX  NITROGEN  220 Kg/ha/year and increase nutrient availability for crop productivity. This is done through their biomass humification and a part of the nitrogen fixed from the air. 

Because of the narrow C:N ratio, the green manures decompose and mineralize fast in soil releasing most of the nutrients,N,P,K etc present in the material.Also the organic acids produced during decomposition solubilize the P and micronutrients present in the soil.Green manures occupy around 60 days and produce limited amount of dry matter.After decomposition,how much carbon is left in the soil to transform into passive pool or humus?What is the carbon sequestration rate per year of growing green manure?What is its contribution to improving soil physico-chemical properties?

Winter annual legume such as hairy vetch Vica villosa can produce up 8 MT dry matter per ha with enough Nitrogen to provide for optimized maize production rates of N fixation between 140 to 220 kg N per ha. Besides providing an organic source rich in nitrogen from the air the cover provides host and habitat for proliferation of greater mycorrhizal fungi which provides the basis for great P nutrition and the improve root colonization improves plant response to periodic drought. With optimized mycorrhizae the need for augmented P to optimize yield requires only one quarter to one third that needed in a fertiler along approach. Moreover,  the incorporation of cover cropping is that soil erosion is greatly reduced. The ability of winter cover cropping can fix between 600 to 1,200 kg C per ha per year. The long term conventional no till maize experiment on clay loam soil in Ohio State Experiment state put no till at 330 kg C per ha per year according to Puget and Lal.  The ability to stimulate the combination of tillage approaches with covers and compost present ability to have additive and synergistic interactions. In addition the ability to use biochar and mixed crop and animal systems are totally encouraging that the soil will be the solution to the greenhouse gas issues in the long run.

Green manures increase nutrient availability for crop growth but the challenges are that legumes such as centrosema, pueraria and stylosanthes do not give farmers both food and income and their application to soils is laborious .I suggest that legumes such as cajanus, lima beans should be planted so that the farmers will derive food, income and increased nutrients supply to the soil for bumper crop yields

We often debate about the residual effect of green manures, how long it is able to sustain ..?. Results are quite variable in field..

The effects on rice yield in terms of percent increase over the control were more pronounced at a site of comparatively lower inherent soil fertility where grain yields of rice grown after high yieldinglegume crops such as bitter lupin (Lupinus mutabilis) and Persian clover (Trifolium resupinatum) were almost twice as high

(up to 7.6 t DM haÿ1) than those of the control treatment (rice after wheat). In contrast, the residual effects of below-ground biomass (roots, nodules) on the following rice crop were not very pronounced and resulted in similar residual effects as rice, after fallow. Although up to 480 kg haÿ1 of legume foliage N had been applied to rice, only a small proportion of the legume N (up to 70 kg N haÿ1

) was recovered by the following rice crop. Total rice dry matter yields were highly correlated with the amount of legume N applied, yet other factors such as residue quality and residue management practices appeared to also affect the magnitude of the residual effects. Future work should aim at investigating the effect of residue quality as affected by legume species and residue management practice on decomposition and N mineralisation processes in rice soils .Source ; Field Crops Research 61 (1999) 37±49

Sparrow, S. D., Cochran, V. L. and Sparrow, E. B. 195. Residual effects of harvested and green-manured legumes on a subsequent barley crop in a subarctic environment. Can. J. Plant Sci. 7S:- 453-456. Experiments were conducted at two locations in Alaska to determine effects of incorporating and harvesting forage legumes on subsequent barley crops. Barley (Hordant vulgare L.) following forage legume crops and fallow had higher yields and plant N than barley following non-Nr-fixing crops. Incorporating, as opposed to harvesting, legume crops sometimes resulted in positive response of barley.

Yes, Green manures or legumes can increase & maintain nutrients & soil sustainability. Legumes have the ability to fix atmospheric Nitrogen through rhizobium bacteria and make it available to plant.@

Yes the green manuring add 40-80 Kg N/ha depending on the type of legume crop used for green manuring and stage of its incorporation in soil.

certainly the legume green manuring increases nutrients availability if other soil and environmental factors are conducive. Nutrients provided by these manuring have long term effect on soil properties and contribute in sustainable productivity.

Avknowledging some excellent replies ,there is no two opinions about utility of green maturing in improving soil fertility but somehow, this traditional practice is getting extinct from modern day agriculture. Can someone throw some lights....

Very good comments I received from great scientists. I would like to express my sincere thanks to all.