It is often claimed  that arid regions have lower crop genetic base than tropical or subtropical regions. This is of the prime reasons of less productivity  of arid regions.

Dr Deka  raised a very good point ,  narrow genetic base of commercial crops in arid regions is perhaps the most pivotal towards lower productivity levels. Unfortunately , expanding aridity coupled  with increasing menace of soil salinity is adding further  fuel to the fire , with the result, challenges to sustain   crop production have multiplied by many dimensions. Abhishek  , you added some very pertinent links , worth reading all of them .

The sustained productivity in arid lands could be achieved through choice of crops/cropping systems, appropriate tillage, appropriate water and nutrients management, appropriate agronomic management  (date of sowing, biofertilizers, crop residues management etc) and effective agri-knowledge dissemination through public/private partmerships

regards

Do you feel that the guiding principles of crop management in annual crops will be different to that of perennial crops ?

My second question is, don`t  you feel crop selection is perhaps most important in addition to soil moisture conservation? We need some responses on these responses.

When it comes to fragile lands prone to desertification overgrazing is a real big issue.

The regeneration of these environments is best addressed with Holistic Grazing systems and mixed farming systems.

Many of the core issues can be overcome when the organic matter of the soil is increased and soil fertility and physical constraints overcome.

Almost all virgin lands had over 5% soil organic matter and their ability to be productive in fragile environments was favored by the wealth of soil organic matter.

Our agricultural systems would do well to concentrate on long term conservation and increase in the soil resource base.

Nice feedbacks , I have received in last 24 hours . Let me respond to all of them one by one. Dr Deka , for sure , the guiding principles  for selection annual crops will be different to what you consider for perennial crops. Crop selection is very important aspect I order to optimize the productivity of arid agriculture. due to consistent water scarcity coupled with lower rains , crops requiring less water requirement , especially under furrow-ridge system is preferred.

Dr Barbara , you have very rightly said . Probably , this is the most cumbersome constraint in arid regions , the evaporation exceeding precipitation plus salinity , makes entire arid regions always on their toes  from management point of view. Crops requiring lesser water requirement , and at the same time , having tolerance against salinity , makes the entire task of crop selection , therefore, doubly risky exercise.

Dr Hepperly , after a long time , received your response , which is so informative and useful as usual. no doubt , arid region soils have vast area virgin due to over -grazing . However , our major concern is   about those cultivated soils. Alkalinity/salinity-induced multiple nutrient deficiencies  further potentially  jeopardise the any positive efforts to  raise the productivity . Interestingly , what is the source of so high organic matter in such virgin lands in arid regions , is it grasses producing siderophores and all.

Nice response my dear  Pierlorenzo . You have added yet another line of thought to whole discussion on microbial inoculation including mycorrhization .   It will be further intriguing to know , what kind of strategy , we need to adopt to ensure rhizosphere health under such moisture stress conditions . Or selecting crops of diversified nature will further expand  the microbial diversity of the soil. Or conservation agriculture practices  like zero tillage ,  floor management using perennial grasses , combination of  deep rooted and shallow rooted crops as a part of  cropping sequence etc etc  will do the world of good to the cause of arid agriculture .

Dear @Anoop, here are some contributions and practices from Serbia.

DEPENDENCE OF THE PRODUCTIVITY OF MAIZE AND SOYBEAN

INTERCROPPING SYSTEMS ON HYBRID TYPE AND PLANT ARRANGEMENT

PATTERN

Strategies for Improving Water Productivity and Quality of Agricultural Crops in

an Era of Climate Change

Challenges for Research Improvements in Agriculture - Programme and Abstracts

BREEDING STRATEGIES FOR BARLEY QUALITY IMPROVEMENT AND WIDE ADAPTATION

http://www.doiserbia.nb.rs/img/doi/0534-0012/2013/0534-00121301135D.pdf

http://cdn.intechopen.com/pdfs/34108.pdf

http://www.area.agrif.bg.ac.rs/sites/default/files/area_conference_belgrade_-_book_of_abstracts.pdf

http://www.pmf.kg.ac.rs/KJS/volumes/kjs26/kjs26knezevicprzulj75.pdf

I feel soil moisture stress couples with salinity will govern the success of cropping sequence. Monitoring  parameters will be changes in organic matter and multiple nutrient deficiencies will be very important.

Arid agriculture is predominantly constrained by shortened growing period due to moisture deficit, high porosity, year round high temperature and limited options for cropping strategies. 

Thanks friends for another set very interesting responses . From last few responses , we can derive , the length pf growing period is  a real constraint despite deep soils , and large scale occurrence of salinity further cuts down the length of growing period. Such conditions offer very limited choice for selection of crops , unless guarded through soil moisture conservation practices.  Of late, arid horticulture is assuming greater importance through perennial arid fruits . Let me invite your views on the suitability of arid horticulture .  

Dr Srivastava thats a very good option for diversifying the agriculture through arid fruits and contributing this way towards higher productivity of arid lands.

Yes , you are right Dr Deka , diversification in agriculture is very important , especially when you are exposed to such diversified constraints as explained our learned colleagues. In a way , such strategy builds up the better land use pattern exploiting the land capability , in addition to better  microbial diversity , with AMFs playing pivotal roles.

Grain yield in arid and semi-arid rainfed environments is highly contingent on, and susceptible to, the amount and timing of rainfall during the growing season. Yield also varies markedly depending on the water-holding capacity of the soil, and management of N and its interaction with stored soil moisture. All these parameters interact in a very complex manner; to fully understand the processes involved by field experimentation alone would be a costly and time consuming task. Using a simulation model such as APSIM can help to integrate these factors and identify better nutrient- and water-management practices to increase crop production in rainfed arid and semi-arid areas, especially when it is combined with long-term climate data and soil information. Hope this short answer would lift parts of your uncertainties.

Peiman  I agree with your statements about the established uncertainities of arid /semi-arid  rainfed agriculture .In such fragile lands as  rightly expressed by Dr Hepperly  , rainfed agriculture adds salt to the wounds , in absence of irrigation . Simulation models exploiting climatic and soil data have shown utility , but on a limited scale , unless further supported by  appropriate optimization at regional scale  . We in India  started  the concept of agroecological regions( 20 ARS) and subregions( 60 SESR) including the soilscape ( Poineered by NBSS&LUP, Nahpur, Maharashtra) . Results have been highly encouraging to not only cereals , but gradually the concept is percolating to land use planning for perennial fruit crops as well. However , million dollar question is , how can we diversify the agriculture on arid lands  with inclusion of arid fruits requiring  much lesser amount of water .

To what an extent microbial inoculations will provide an additional guard to plants to fight against moisture deficit and salinity in arid lands despite soils being so low in organic carbon content.

I  always keep saying , microbial diversity in a given soil type is a function of soil behavior . And , microbes have huge adaptability as per soil conditions . in arid soils , where salinity is a major issue , microbial inoculation lessens the impact of the salt -induced osmotic stress .Role of AMs along with highly AM-dependent crops  could be seen pivotal  in this regard . Find enclosed one PDF for further reading .

Organic matter content in arid soils is very poor so the soils doesn't have the basic structure and properties which require for the rapid crop growth and supplying nutrients to the crop.

This is perhaps one of the main hurdles on arid soils to take utmost advantage of microbial inoculation , despite all out efforts    , and equally pressing reasons as well for lower nutrient-use-efficiency vis-à-vis crop production. In this regard , I still remember many reports from arid parts of USA  , where simply due to very low organic carbon content , the response of biofertilization is  reported   so abysmal.

But lets suggest some commercially viable cropping sequence adopted across. Any long term studies undertaken?

Agriculture and Improving Water Use Efficiency! 

"...Given the limitation for enhancing the availability of utilizable water resources and challenge of variable supplies due to exacerbating climate change impacts, National Water Policy 2012 gives priority to demand management especially through bringing in maximum efficiency in use of water and avoiding wastage.

Micro-irrigation techniques offer promising solution to enhance the water use efficiency in irrigation sector.  These techniques optimize the use of water and energy, while ensuring better crop yields as compared to conventional practices.

With the goal envisaged by National Water Mission to enhance the water use efficiency by 20%, adoption of micro-irrigation techniques and other scientific water management practices could pave the way for future water security and reducing the inter-sectoral conflicts for water demand. This has potential to further contribute to the food and energy security in the country. Additionally, enhancing irrigation water use efficiency through micro-irrigation techniques will contribute to the environmental sustainability, by saving water, reducing drainage hazard, and reducing farm inputs among other benefits...

For successful adoption of any technology, there is a need to build capacity of the users first and also to create awareness amongst the relevant stakeholders, including state and central government authorities, manufacturers, and researchers who jointly can undertake a mass awareness program to promote micro-irrigation techniques. Case studies of the best practices of micro-irrigation examples could be disseminated to encourage farmers...."

https://www.linkedin.com/pulse/agriculture-improving-water-use-efficiency-vivekanand-honnungar-ph-d?trkInfo=VSRPsearchId%3A577811291458241511655%2CVSRPtargetId%3A6980154652981079986%2CVSRPcmpt%3Aprimary&trk=vsrp_influencer_content_res_name

Ljubomir , very good point , you raise about the necessity of adopting micro-irrigation , since in arid areas , water quality by and large , is also not of good quality from safe irrigation point of view. we can further link it with fertigation  to ensure batter water- as well as nutrient-use -efficiency coupled with crops capable of  sustaining under water deficit conditions . 

In arid regions, which kind of crops offer better ecological service in addition to quality production of crop.

Dear Anoop Kumar Srivastava,

Subsurface irrigation And Drip Irrigation can get More Agriculture Productivity and also can Make Crop Rotation, These leads to More Benefits as well as various Cultivation .

These type of Irrigation , without wastage of water that can be feed the water only the Root Zone.

Sir In Arid Regions Cotton , Water Melon , Corn , Cucumber and Lemon 

 Dr Deka , yes , it is not only true fro perennial crops but annual crops as well offer ecological service  through carbon sequestration as a function of photosynthesis minus respiration . Ponkumar,  your response very well perceived , i agree with you . Can you suggest some well established cropping sequence as a success story of arid regions ?. 

Dear Anoop Kumar Srivastava,

In Arid Regions Cotton , citrus, Water Melon , Corn , Cucumber ,Lemon And various nut crops.

I am talking of the crop  sequence Ponkumar   adopted in different regions and different soils to judge the inter-compatibility amongst crops , since arid ecosystem occupies 12% of the area in India including cold arid and hot arid regions ( Total area 39.5 million ha , mostly concentrated in states like Rajasthan , Gujarat ,Punjab, Haryana, Andhra Pradesh , Karnataka , Maharashtra ). The present  cropping pattern of the arid region can be classified into two categories viz., areas represented by assured irrigation and areas represented by rainfed agriculture . These two types of conditions offer different scenario for different crops. Hope to get back your nice response.  

I am from Kordufan rejoin  in the center of Sudan, Almost all crops are rain fed:

the main products of our rejoin  are : sorghum - millet - Okra for domestic consumption

 but we have economic crops as well

 Sesame - Hibiscus - and  ground nut 

 very large part of  the rejoin in 1980th exposed to  drought and desertification  

Actually most of  the farmers are working  by their accumulative experience   without  agri. guidance  or any type of technical support , According to my observation they have no clear cropping plans, but they get good crops with good rain seasons 

you will find below a link to the strategic decisions upon  climate change in the region       

http://www.wri.org/our-work/project/world-resources-report/climate-change-adaptation-and-decision-making-sudan

 Very informative feedback Saifeldin , appreciate it . What about the irrigated arid areas , do same crop sequence fare well , or its altogether different sequence is adopted ?. Whether or not  , nature and properties of soil are taken into consideration while deciding the cropping sequence ? What kind crop advisory dpending upon the available resource inventrory of farmer  from the Agriculture Department is given to them in such arid areas?

Friends do you feel that cropping sequence in irrigated arid areas will be different to that of rainfed arid areas. what are the guiding principles of two contrasting eco-systems?

I do not think that guiding principles of selecting crops in rainfed arid soils will vary much  compared to irrigated arid soils.

Such guiding principles will surely vary when you compare rainfed versus irrigated crops in not only arid region , but under any given agro-ecosystem.

Dear Mr Kumar 

 last time you asked me a bout the soil 

 I have no scientific description exactly: there is sandy soil- light red soil - light clay at  near the  valley

 however you will find within the below attachment some pictures which will give you an idea

 regards 

SAIF

https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTtwYFyt5TXhRodrq8ePM4rLBAEXZURTrnSBA9dQ4AUq1pIgHa-

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTt6Ry1Pa8fb9sUm8ICyBRx8Uv5Khgjo1LuSAG6FIJzJ6PGMiDfzw

https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSsZub1OpTBNTsoW5GCI8sH_qtUoIKeV0FNfubHBvojiLMbZL4njg

https://www.google.com.sa/imgres?imgurl=http%3A%2F%2Fwww.sudannewdawn.com%2Fup%2Fuploads%2F13704134881.jpg&imgrefurl=http%3A%2F%2Fsudanelite.com%2Fvb%2Farchive%2Findex.php%2Ft-17477.html%3Fs%3Da327928c52975c68794d05a495d7eee9&docid=pkvvd0OSGUYS6M&tbnid=1maVKw_zUjMfjM%3A&w=640&h=480&ei=dgHwVqHpH4O8PYTWmrAH

What kind of management practices , we need to practice to sustain the crop performance both temporally as well as spatially . Cropping sequence , water management , conservation practices , salinity issue , rains remaining confined to only few days by and large , etc we have debated. But , they need real reorientation according to soil type and water resource   availability .

In my view, in arid regions the rainfall is much lower so the leeching process is not fair enough to leech salts from the surface. It may also depends on region to region in arid areas.

the crops selection in arid areas should be those which needs less water, and which can overcome salt stress upto some extent. It may also includes some plants which are transgenic or salt tolerant.

The other way to cop with the situation is to add some beneficial microrganisums, which manily includes AM fungi. Studies have shown that the AM fungi can help plant upto some extent under said circumstances.

I do agree with you Hussain  about the kind of guiding principles of arid agriculture . The most important is perhaps the information on individual crop requireemnt or cropping sequence , so that both are usper-imposed over each other to arrive at some keys to success on a given soil type , and at the same  time ,  the resources are befittingly used , much to the advantage of the crop. Or do you feel , any other course of action?

Friends,how do you foresee the role of soil inhabiting microbes in neutralizing the effect of soil moisture deficit.

Dr Deka , the role of  microbes , now not only in arid environment (where there is a consistent deficit of soil moisture , besides other abiotic constraints) , but in all the soil environments, has to be seen beyond  soil fertility reactions , in terms of soil health resilience vis-à-vis crop health , besides moderating the accumulation of heavy metals in ternary soil system . AMFs have the most profound task in this regard , activates the inoculated plants to face the abiotic stress more emphatically than non-inoculated plants. Crop specific microbiome consortium has now come into practice , and this concept need to be expanded to as many crops as possible so that crop-microbe nexus can be befittingly exploited towards sustaining the productivity potential of any crop in such arid environment .    

Dear Anoop Kumar Srivastava,

Sorry Sir  Busy with National Conference that's why I couldn't Reply .

Sir ,The Crop Rotation for  Rain fed Agriculture     

Groundnut  - Black Eye Beans [ Grams ] ( Or ) Millets [ Thinai ]

Groundnut and millet are grown in arid lands of Sudan in addition to Hibiscus  

interesting feedbacks  Dr Ponkumar and Saifeldin . Any information  about fruit crop -based cropping sequence ? What about the fields being kept fallow for how much time ?.

Dear Anoop Kumar Srivastava,

In Rain fed agricultural Fruits Mostly Seasonal long duration and Medicinal Fruits also ,  

Gooseberry ,Tamarind and Sugar Palm Fruit

Thanks Dr IIango . Infact , we were more willing to see, a comprehensive cropping sequence , which includes such fruit crops tolerant to extreme aridity . how do you address calcareousness in these soils ?  

In our drier part of the country- farmers are shifting their land for orchard based agriculture like:

(1) Mango/Guava+rice-Fallow-Fallow

(2) Mango/Guava+rice-Mustard-Fallow

(3) Mango/Guava/Ber+rice-Wheat-Fallow

Rainwater harvesting is another point in mini-ponds

Dr Biswas , that's a very useful information . If you can attach some published literature , it will be still good for all of our colleagues , I appreciate your feedback on the issue.

Dr Anoop,

Pls see uploaded book chapter for your kind information.

Thanks so much Dr Biswas . Its really interesting .

Addressing soil salinity under moisture stress and their relation with water requirement is most important in arid agriculture.

Yes , i do agree with you Dr Deka , salinity and water stress doubles the miseries of  crops to be grown under arid environment , thereby , reducing  the efficiency of both water and nutrients.  

OK, Dr. Kumar because Sikha Deka point is strong and important

In arid regions soil and water conservation engineering is perhaps most important besides use of drought tolerant crops in cropping sequence. 

Simple reason , salinity infestation and aridity are so inter-linked with each other , since most of salinity/sodicity is much confined to arid regions only , either  regionally or globally...

I agree with you Dr Srivastava, majority of salinity emerge from arid regions only. 

I agree with Parmeshwar and Anoop that salts are fundamentally an issue where precipitation is less than the evaporation and evapotranspiration leading to surface accumulation of the salty materials. 

Conversely acidity is the result of long term precipitation excessing the evaporation and evapotranspiration leading to the depletion of salts and the increase in an acid infertile situation. 

H. Jenny does an excellent job of explaining this big picture and his ideas are extended by Wm. Albrecht  linking health to the status of the soil resource. 

Throughout the world the best soils have developed where the precipitation and evaporation are near equal and the permanent cover is prairie which ruminant animals dominate. 

In the prairie system lie the secrets of optimized soil systems. This probably explains the astounding success of holistic grazing in soil improvement as it mimics the tried and true system which couples permanent cover with recycling of the manures without mining the soil. 

The majority of the whole world will find themselves in a arid or humid climate and their soil resources will be compromised.

As such we need the appropriate strategies in all these situations to leverage our soil resource to maximize the benefit to our human society and the environment. 

Good literature by Raj, thank you.

Very good reply Abhishek, how a soil moisture stress under arid region prepares the plant to face salinity and perform to optimum ?

Abhishek , how rich is your Pandora box of literature , quite fascinating to see these so useful links..let me read all of them , to be in a position to respond..Thanks for attaching  some worth reading materials.

Very good response Abhishek, What are the water management interventions in improving the crop productivity in arid regions ?

Abhishek , no one can match your ability to trace the literature in as quick time as you can do ..appreciate it 

More than 65% of cereal croplands worldwide are rainfed, accounting for 58% of world cereal production. Moreover, with the decreasing availability of irrigation water for agriculture, there is an increased need for enhancing crop productivity under rainfed conditions. Currently, irrigation accounts for around 70% of water withdrawals worldwide and 90% in low-income developing countries, but due to rapidly increasing domestic and industrial demands for water in many developing countries, serious limitations to irrigated agriculture are foreseen.

Increasing crop productivity in arid and semi-arid areas is widely recognized as difficult. This is mainly due to highly erratic and low rainfall as well as degraded soils deficient in plant nutrients. To meet the increasing demand for food, farmers in many developing countries have expanded rainfed agriculture into marginal lands that are susceptible to environmental degradation, particularly soil erosion. Nutrient mining is a common application of adequate amounts of fertilizers to replenish nutrient uptake by crops and losses but is not a viable option for most resource-poor farmers in these regions. As a result, crop productivity of rainfed regions is low. For example, cereal yields in rainfed areas of developing countries rarely exceed 1.5 t ha–1, less than half those of rainfed cereals in developed countries. Nevertheless, there is some evidence that crop yields in these regions can be profitably increased and yield variation decreased with a combination of careful management of natural resources and low inputs of chemical fertilizers. Since nearly two-thirds of the rural population of developing countries live in these less-favoured areas, there is an increasing demand for exploring such management practices for improving soil fertility and increasing crop production. In this regard, isotopes and nuclear techniques play a crucial role in providing valuable quantitative information on nutrient release from crop residues and fertilizers and uptake of nutrients and water by crops for identification of promising management practices for optimising crop production under rainfed conditions.

Investments in soil and water conservation are supposed to contribute to dryland crop yield improvement by rehabilitating the productive capacity of the land. On the basis of farmers’ interviews, group meetings and field visits, we explore the main constraints for dryland crop yield improvement. We find that investments in soil and water conservation do not have a significant impact on dryland yields, at least not under prolonged conditions of drought. Besides, access to irrigation as a result of investments in water storage and conservation tends to lead towards more water-intensive crops instead of to supplemental irrigation to improve dryland yields. Also, we find that low production potential might not be the biggest constraint: Low economic returns, changing household diets, failing markets and poverty seem to constrain dryland crop yields even more. ( Source : Bouma and Scott )

Some useful thoughts....

Thanks Abhishek for appreciating . Hope , we will continue to interact on  some more scientific issues with much stronger participation . Please  keep the tempo of such interaction .....

How do you feel whether integrated farming system will be affected and let us compare the practices of arid versus humid region ?

Dr Shirgure , the arid soils are more challenging than humid soils , simply because of soil moisture driven factors collectively affect the crop performance to a considerable extent , coupled with high soil pH, compared to  soil conditions  under humid regions..

Of course, arid soils have lot of problems starting from their genesis when salt content cannot fully leach down due to less rainfall and these just remain in the profile. Then these pose multi-sided problems later on. 

Dr Nazir, how to arrive at the most pressing issue of arid horticulture having most dominant  impact on crop performance in a given climatic situation and soil type ? 

Good response Abhishek. You are right soil salinity and moisture stress are two premier constraints that agriculture has to fight , whether it is annual crops or perennial crops...

Yes, Dr. Kumar, if we can manage these two, we can solve many problems of agriculture.

Well said Dr Nazir, 

Dear Anil Kumar Singh,

I believe your insight that agriculture technologies and principles will be key factors in combating the adverse consequences of salinity issues in the arid region is right on the spot.

I would add that the comprehensive systematic of agricultural systems with energy and the environment are key in this respect. 

The overall limiting factor for supporting our planetary system is available and clean water at economical prices.

In arid regions around the world this means the ability to desalinize water is critical. As this abundant low cost resources is unleashed the major tool to deal with salinization will be available and the growing ability to feed our growing population will be accomplished.  Not only can we do indeed we must do it. 

One of technologies which is very potentially useful would be Ocean Thermal Exchange and Conversion OTEC. This technology has been demonstrated in Hawaii the harvest of deep cool water when brought to the surface can be used for net energy production. The nutrient rich deep water is put into terrestrial ponds for algae production.

Cool saline water in an enclosed drip irrigation system can result in capture of humidity from the air as dew. The cooled soil makes the crops grow optimally as a too hot rooting environment is modified to favor plant development. 

One can envision the use of wind power as a resource that would desalinize water using renewable energy that is not polluting and contributing to greenhouse gases.

The new wave of solar technologies will make the desert the renewable OPEC and the agriculture system can be incorporation in this revolution which have been seeded in technological advancements. 

Because of rapid explosion of global technology and innovation this is an exciting time to be alive. 

Some thoughts.

Nice responses from Dr Hepperly and Dr Anil Kumar , appreciate both you . No , doubt , the technologies addressing the issues  of arid agriculture , will one or other way , will aid in moderating the negative consequences of climate change , since climate change related aridity on an average will be on the continuous rise. 

Yes, Dr. Kumar, aridity will be on the rising side in arid zones as result of climate changes and increase salt accumulation as well. Therefore, we have to be extra careful now. Our negligence will be punished  heavily in the shape of spreading of salt affected soils. 

Dr Nazir and Dr Srivastava  I agree with both of you. In arid region only we need to aspire for better farmer friendly technology in relation to climate change.

Thanks both of you again , Dr Nazir and Dr Deka. Our major concern in arid region is to look at the possible shifts in crops phenology of different crops, we need accordingly the readjustment in fertilizer and irrigation scheduling , while considering the imapct of climate change . Dr Anil Singh raised this issue, which i feel is very pertinent ..

Dr. Kumar's point is very valid, every one has to think about it.

Dr Srivastava, you have put up a very valid point. But, how can we visually identify this any shift in crop phenology and then work out the nutrient and water requirement. That will be the best course of action.  

nice feedback . Dr Anil Kumar , you will agree with me , many a time s, it becomes doubly difficult to delineate , what kind of practices deserve to be advocated under normal methods of farming , how shall they be different under a climate change scenario..?

Thanks Dr Anil Kumar , but how to address the associated changes emerging out of climate change ..?

Here is the right concept , adopting only ISFM will never solve the dynamisms associated with climate change  . It becomes really multi-pronged in nature considering the fact  to maintain the sustainable growth of agriculture on one hand, keep safeguard against any possible deterioration in soil health, and addressing such a harriculean task of climate change, on the other hand  , make the entire agriculture all the more complex . We need to keep a consistent vigil  on these issues  before climate smart soil fertility management becomes too speculative..

Use of biochar reduces CH4 and N2O emissions (pls see the attached paper). Is there any references on microbes? Climate smart soil management can sequester C in soil for a long time.

Dear J C Biswas, In relation to benefits of biochar the information on mycorrhizae and biological nitrogen fixation are fertile areas of review. 

Rondon et al 2007. Biological nitrogen fixation by common beans increases with biochar. Bio Fert Soil 43(6):699-708. Can be a good example.

The symbiosis is the best area to exploit for more sustainable agricultural systems. 

Thanks Dr Biswas  for raising an issue relating biochar vis-a-vis soil microbial shifts in structural as well as functional diversity .. Here are some literature for  your reference please. Hope , they will be useful..

A. H. LONE, G. R. NAJAR, M. A. GANIE, J. A. SOFI, T. ALI. 2015. Biochar for sustainable soil health: A review of prospects and concerns (Title in Chinese:生物炭对土壤可持续健康的影响：探索和热点综述). Pedosphere. 25(5): 639--653. Abstract: Biochar as a soil amendment is confronted with the challenge that it must benefit soil health as it can be by no means separated from soils once it is added. The available literature even though sparse and mostly based on short-term studies has been encouraging and the trend obtained so far has raised many hopes. Biochar has been reported to positively impact an array of soil processes ranging from benefiting soil biology, controlling soil-borne pathogens, enhancing nitrogen fixation, improving soil physical and chemical properties, decreasing nitrate (NO3-) leaching and nitrous oxide (N2O) emission to remediation of contaminated soils. However, very little biochar is still utilized as soil amendment mainly because these benefits are yet to be quantified, and also the mechanisms by which the soil health is improved are poorly understood. Due to the infancy of research regarding this subject, there are still more questions than answers. The future research efforts must focus on carrying out long-term experiments and uncover the mechanisms underlying these processes so that key concerns surrounding the use of biochar are addressed before its large scale application is recommended. View Full Text at http://www.sciencedirect.com/science/article/pii/S100201601530045

H. M. ANAWAR, F. AKTER, Z. M. SOLAIMAN, V. STREZOV. 2015. Biochar: An emerging panacea for remediation of soil contaminants from mining, industry and sewage wastes (Title in Chinese: 生物炭：一种新型改良剂能修复矿物、工业以及污水废弃物污染的土壤). Pedosphere. 25(5): 654--665. Abstract: Mine tailings, waste rock piles, acid mine drainage, industrial wastewater, and sewage sludge have contaminated a vast area of cultivable and fallow lands, with a consequence of deterioration of soil and water quality and watercourses due to the erosion of contaminated soils for absence of vegetative cover. High concentrations of toxic elements, organic contaminants, acidic soils, and harsh climatic conditions have made it difficult to re-establish vegetation and produce crops there. Recently, a significant body of work has focused on the suitability and potentiality of biochar as a soil remediation tool that increases seed emergence, soil and crop productivity, above ground biomass, and vegetation cover on mine tailings, waste rock piles, and industrial and sewage waste-contaminated soils by increasing soil nutrients and water-holding capacity, amelioration of soil acidity, and stimulation of microbial diversity and functions. This review addresses: i) the functional properties of biochar, and microbial cycling of nutrients in soil; ii) bioremediation, especially phytoremediation of mine tailings, industrial waste, sewage sludge, and contaminated soil using biochar; iii) impact of biochar on reduction of acid production, acid mine drainage treatment, and geochemical dynamics in mine tailings; and iv) treatment of metal and organic contaminants in soils using biochar, and restoration of degraded land. View Full Text at http://www.sciencedirect.com/science/article/pii/S1002016015300461

Thanks Dr Hepeprly for bringing up another issue afresh to discuss .This is the area , we are most missing with reference to evaluation of biochar -compost synergy or biochars composted with organic manures , or even comparing the biochars and compost produced from similar feedstocks. This will add another dimension to soil fertility management in arid regions where moisture stress and alkalinity move together , besides soil salinity...

Dr Paul, Dr Anoop and Dr Abhishek.

Thanks a lot for the insight and linkages. In our initial study with biochar (from rice husk) in variable combinations of P sources and beneficial microbes, we found very promising effects on crop performances under reduced N & P rates. We might be able to share in future. Regards