Assessment of Biomass Production and Carbon Sequestration in Fruit Tree–Based Agroforestry Systems of the Semi-Arid of Vindhyan Region in India

In the fight against a warming planet, the air itself holds the key to understanding the problem: carbon dioxide. This gas, released when we burn fossil fuels or clear forests, traps heat and drives climate change. While much of the conversation focuses on stopping emissions, there is a parallel strategy that has gained serious attention: taking carbon out of the air and storing it safely in the ground and in living things. Trees are particularly good at this. As they grow, they pull carbon from the atmosphere and lock it away in their wood, roots, and leaves. When these trees are planted alongside crops on farmland, a system known as agroforestry, they can do double duty. They provide food and income for farmers while simultaneously acting as a massive sponge for carbon, turning a piece of agricultural land into a living carbon bank. The question for scientists and policymakers is not just whether this works in theory, but how much carbon different types of trees can actually store in specific, difficult environments, and whether farmers can make a living while doing it.

Researchers in the semi-arid Vindhyan region of India set out to answer these questions by measuring the carbon storage potential of two specific fruit trees: bael and guava. This area, characterized by shallow soils and seasonal droughts, is home to many small farmers who rely on the land for their livelihood. The scientists wanted to see if planting these trees in orchards, while also growing short-term crops like black gram and sesame in the spaces between them, could store significantly more carbon than growing those crops alone in open fields. They established a large field experiment with twelve different plots, testing various combinations of the two fruit trees with two varieties of each intercrop. Over the course of the growing seasons, they carefully measured the size of the trees, the weight of the crops, and the amount of carbon stored in the soil, comparing these results against plots where only the crops were grown without any trees.

The results painted a clear picture of the transformative power of adding trees to the landscape. The plots containing fruit trees accumulated vastly more biomass—the total weight of all living plant material—than the open fields. The bael-based systems, which combined the drought-tolerant bael tree with black gram or sesame, produced the most impressive results, accumulating between 50.1 and 56.2 tonnes of biomass per hectare. The guava-based systems also performed well, storing between 31.3 and 38.0 tonnes per hectare. In stark contrast, the plots with only the annual crops, the sole-crop controls, produced a mere 1.8 to 3.1 tonnes per hectare. This massive difference meant that the tree-based systems were not just slightly better, but orders of magnitude more effective at capturing plant matter. The carbon stored within this biomass followed the same pattern, with the bael systems holding between 27.1 and 30.8 tonnes of carbon per hectare, compared to less than 1.6 tonnes in the open fields.

Beyond the trees and crops themselves, the study also looked at what was happening beneath the surface. The researchers measured the soil organic carbon, which is the carbon stored in the soil itself, a critical component for long-term climate mitigation. They found that the soil under the tree-based systems was richer in carbon, ranging from 0.42 to 0.51 percent, compared to 0.34 to 0.37 percent in the open fields. When they added the carbon stored in the trees and crops to the carbon stored in the soil, the total system carbon for the bael plots reached between 45 and 50 tonnes per hectare. The guava systems reached between 34 and 39 tonnes per hectare. This total storage is a significant achievement, suggesting that these orchards are acting as substantial reservoirs for carbon that would otherwise remain in the atmosphere.

The study also calculated how fast this carbon was being captured. By estimating the age of the trees and the seasonal growth of the crops, the researchers determined that the agroforestry systems were sequestering carbon at a rate of 1.9 to 3.4 tonnes per hectare each year. This is a steady, reliable rate of removal that far exceeds the negligible amounts captured by the sole crops. The most efficient combination turned out to be the bael tree paired with the black gram variety known as Shekar-1, which achieved the highest rates of carbon capture and the greatest total biomass. The researchers noted that while the trees provided the bulk of the carbon storage, the intercropped plants were still vital. They contributed a small but meaningful amount of carbon, and more importantly, they provided farmers with an annual harvest and income stream while the trees were still maturing. This dual income stream is crucial for convincing farmers to adopt these systems, as it ensures they do not have to wait years for the trees to bear fruit before seeing a return on their investment.

These findings offer a concrete path forward for climate action in regions like the Vindhyan plateau. The data shows that well-managed fruit tree orchards can deliver meaningful climate benefits without sacrificing agricultural production. The bael and guava trees proved to be resilient choices for this semi-arid environment, capable of thriving where other crops might struggle, while simultaneously building up the soil and storing carbon. The study suggests that these systems are not just theoretical models but practical, working solutions that can be scaled up. By quantifying exactly how much carbon these systems store, the researchers have provided the necessary evidence for policymakers to include such agroforestry practices in regional climate plans and payment schemes. This would allow farmers to be rewarded for the carbon they store, turning their land into a source of both food and climate stability. The work confirms that in the hands of local farmers, these mixed systems can support livelihoods while quietly and effectively pulling carbon out of the air, one tree and one crop at a time.