The world faces two enormous challenges that can be met, at least in part and at low cost, by making certain changes in agricultural practices. There is need to produce enough food and fibre for a growing population in the face of adverse climatic trends, and to remove greenhouse gases to avert the worst consequences of global climate change. Improving photosynthetic efficiency of crop plants can help meet both challenges. Fortuitously, when crop plants’ roots are colonized by certain root endophytic fungi in the genus Trichoderma, this induces up‐regulation of genes and pigments that improve the plants’ photosynthesis. Plants under physiological or environmental stress suffer losses in their photosynthetic capability through damage to photosystems and other cellular processes caused by reactive oxygen species (ROS). But certain Trichoderma strains activate biochemical pathways that reduce ROS to less harmful molecules. This and other mechanisms described here make plants more resistant to biotic and abiotic stresses. The net effect of these fungi’s residence in plants is to induce greater shoot and root growth, increasing crop yields, which will raise future food production. Furthermore, if photosynthesis rates are increased, more CO2 will be extracted from the atmosphere, and enhanced plant root growth means that more sequestered C will be transferred to roots and stored in the soil. Reductions in global greenhouse gas levels can be accelerated by giving incentives for climate‐friendly carbon farming and carbon cap‐and‐trade programmes that reward practices transferring carbon from the atmosphere into the soil, also enhancing soil fertility and agricultural production.

Plants exist in close association with uncountable numbers of microorganisms around, on, and within them. Some of these endophytically colonize plant roots. The colonization of roots by certain symbiotic strains of plant-associated bacteria and fungi results in these plants performing better than plants whose roots are colonized by only the wild populations of microbes. We consider here crop plants whose roots are inhabited by introduced organisms, referring to them as Enhanced Plant Holobionts (EPHs). EPHs frequently exhibit resistance to specific plant diseases and pests (biotic stresses); resistance to abiotic stresses such as drought, cold, salinity, and flooding; enhanced nutrient acquisition and nutrient use efficiency; increased photosynthetic capability; and enhanced ability to maintain efficient internal cellular functioning. The microbes described here generate effects in part through their production of Symbiont-Associated Molecular Patterns (SAMPs) that interact with receptors in plant cell membranes. Such interaction results in the transduction of systemic signals that cause plant-wide changes in the plants’ gene expression and physiology. EPH effects arise not only from plant-microbe interactions, but also from microbe-microbe interactions like competition, mycoparasitism, and antibiotic production. When root and shoot growth are enhanced as a consequence of these root endophytes, this increases the yield from EPH plants. An additional benefit from growing larger root systems and having greater photosynthetic capability is greater sequestration of atmospheric CO2. This is transferred to roots where sequestered C, through exudation or root decomposition, becomes part of the total soil carbon, which reduces global warming potential in the atmosphere. Forming EPHs requires selection and introduction of appropriate strains of microorganisms, with EPH performance affected also by the delivery and management practices.

In the past half dozen years, farmers and professionals working with them in several Asian and African countries have begun adapting and extrapolating what they have learned from and about the system of rice intensification (SRI) to a range of other crops -finger millet, wheat, sugarcane, tef, oilseeds such as mustard, legumes such as soya and kidney beans, and various vegetables -in what is being called the system of crop intensification (SCI). As with rice, the principles of early and healthy plant establishment, reducing competition between plants, increased soil organic matter, active soil aeration, and the careful application of water are proving able to raise the productivity and profitability of differently-managed crops. Recent reports from the World Bank in India and the Agricultural Transformation Agency in Ethiopia show such changes in crop management improving food security and being scaled up with hundreds of thousands of farmers. This review article reports on the productivity and other impacts being observed for many different crops in half a dozen countries for increasing food crop yields with lower cost and input requirements as well as more resilience to adverse effects of climate change. It also reports on mechanization innovations that reduce labor requirements for these methods.

With continually increasing demand for food accompanied by the constraints of climate change and the availability and quality of soil and water, the world's farmers are challenged to produce more food per hectare with less water, and with fewer agrochemical inputs if possible. The ideas and methods of the system of rice intensification which is improving irrigated rice production are now being extended/ adapted to many other crops: wheat, maize, finger millet, sugarcane, tef, mustard, legumes, vegetables, and even spices. Promoting better root growth and enhancing the soil's fertility with organic materials are being found effective means for raising the yields of many crop plants with less water, less fertilizer, reduced seeds, fewer agrochemicals, and greater climate resilience. In this article, we review what is becoming known about various farmer-centred innovations for agroecological crop management that can contribute to agricultural sustainability. These changes represent the emerging system of crop intensification, which is being increasingly applied in Asian, African, and Latin American countries. More research will be needed to verify the efficacy and impact of these innovations and to clarify their conditions and limits. But as no negative effects for human or environmental health have been identified, making these agronomic options more widely known should prompt more investigation and, to the extent justified by results, utilization of these methodologies.