The question asks for the best integrated strategy to address issues like soil pollution, falling crop yields, and low microbial activity near an industrial zone. Let's analyze the options:

1. Reforestation in nearby urban centers: While reforestation helps in improving air quality and reducing urban heat, it does not directly address soil pollution, crop yields, or microbial activity in agricultural land adjacent to industrial zones. Hence, this option is not the best solution for the given problems.
2. Ban all regional chemical fertilizers: Banning chemical fertilizers could reduce soil degradation, but it may also negatively impact crop yields, especially if no suitable alternatives like organic fertilizers are used. Additionally, chemical fertilizers are not necessarily the main cause of industrial pollution. Thus, this option does not effectively integrate all aspects of the problem.
3. Control industrial waste for sustainability: This is the correct answer. By controlling and properly managing industrial waste, the release of harmful pollutants into the soil can be minimized. This directly reduces soil pollution, protects crop yields, and maintains healthy soil microbial activity. It addresses the core issue affecting the agricultural lands near industrial zones.
4. Expand urban areas into farmland: Converting farmland into urban areas may further degrade arable land, reducing available space for agriculture. Moreover, it does not address the issues of pollution or microbial health. Hence, this option is counterproductive.

Given the analysis, the best strategy is third option: "Control industrial waste for sustainability." This method directly targets the root of the problem by reducing pollutants entering the agricultural ecosystem, thus promoting a healthier environment for both the soil and crops.