What do crops of the green revolution need in order to produce higher yields?

These crops where improved  with technology, production of high-yielding variety, and improve farm practices. All these ensured  the crops of green revolution had increase yield.

Explanation:

Through  genetic engineering, high-yielding variety of cereals e.g wheat, maize, rice, were genetically engineered so that certain features which enhanced increased productivity were selected for.

Use of fertilization, the adoption of mechanization,good cropping and farming system are other factors which enhanced yield of these crops. Specifically, these crops were modified to enhance their Nitrogen uptake, which promotes rapid growths.

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where is the scientific experiment?