Very valuable crops like large cardamom, black pepper, tea, coffee and others can be grown  in this region.

Much more precise information on soils, land cover and actual land use is necessary.

Dear Doctor Singh,

Even with acid tolerant crops the potential for compromised productivity is through the general infertility. Thus I believe that idea is to concentrate on the scarcity of micronutrients which can cause macro problems. I would need to see what your soil micro nutrient status is by foliar analysis on your crops compared to optimized results in the literature. In an acid soil situation the liming to point of eliminating iron, aluminum and manganese would potentially be the best approach but not trying to get to neutral which would be overkill. The other issue what are major nutrient status. I believe that the use of raised beds will be very important as well as drainage and soil conservation planning. The use of shade tolerant low growing legume would be highly beneficial such as ornamental peanut as part of that planning. 

The importance of free and available Calcium in this situation needs further investigation. Please see below link.

Good luck!

Dr.Singh has raised an important issue of improving the productivity of crops in acid  soils in fragile ecosystems of Northeastern part of India.I compliment Dr.Mitra for providing good information on soils, crops and agricultural production problems and opportunities.As the area is mountainnious and hilly terrain, only 7% of the reported area is under cropping. 5.3 million ha cropped land is supporting nearly 39 million people. Around 2.2 million ha is  under Jhum/slash and burn agriculture. Soil erosion, loss of biodiversity and nutrients depletion are common problems. Around ,17.5% of the Jhum land is cultivated at a particular instance.80% of the  cropped area is under cereals especially rice.Maize is dominant cereal crop in Sikkim. Oilseed crops occupy 6-9% area.Water availability for irrigation is problem,though the area receives very heavy rainfall during monsoon period and the rest of the period is dry.Irrigated area is around24% and Fertilizer use is 23 kg/ ha.As the agricultural lands occupy less area, the people in the area can not become self sufficient in foodgrain production. But they can grow high value spices,horticultural and plantation crops.Some promising fruit crops are pineapple, citrus(orange)and banana.Among plantation crops,tea coffee,arecanut are important.The production of high value spices is also important. The area needs soil and water conservation and water harvesting. on priority.The slash and burn system should be discouraged especially in high elevation slopes.Innovative technology need to be followed in agriculture in the fragile ecosystems of Northeastern India.

Two acid tolerant food crops that could work under the Northeastern India condition may be cassava and sweet potato. The use of intercropping can utilize the sweet potato as a productive ground cover which gives an early crop in about one half the time for cassava. In central America the use of velvetbean as an interplanting allows for all of the Nitrogen requirements for maize and can control difficult perennial weeds.

A local landscape approach is necessary . It will include stakeholders participation on the basis of  land facets and land units. Soil fertility potential of each land facet need to be well understood on the basis of this reference: "Sanchez P.A., Palm C.A.and Buol S.W., 2003, "Fertility capability soil classification: a tool to

help assess soil quality in the tropics", Geoderma, 114, 157–185."

Dr.Hepperly and Dr.Luc,good suggestions. Land scape based based management of soil and water resources is must for sustainable agriculture. In smallholders fields intercropping systems may meet their  basic food needs.

Can any body working in the North East supplement on the extent of diversified farming being practiced ?Diversified farming may provide more livihood and food security as the farmers can get employment and income throughout the year.Of course rainwater harvesting is an important component to support multienterprizes.

North-east India is having lot of diversity even more than rest of India. Niche based high value crops cultivation may fetch better returns to the farmers and improve their livelihood. Policy interventions are needed in processing and marketing of these niche crops. In the name of food security within state, we are compromising geographical advantage to cultivate niche crops which possess very high quality and value.