The residue-to-product ratio (RPR) is used to calculate how much unused crop residue might be left after harvesting a particular crop. Also called the residue yield or straw/grain ratio, the equation takes the mass of residue divided by the mass of crop produced. On average, 1.44 tonnes acre−1 and 1.32 tonnes acre−1 of residues are produced from rice and wheat crop, respectively.

A thumb rule, a meter-long stick marked into 25 equal segments, may be used to measure crop residues. The stick is placed at right angles to crop rows, beginning at one row. Percent crop residue cover is measured by counting the number of marks that lie directly over a piece of residue, and multiplying by four.

Estimation of animal waste etc-

Manure production = Number of Cattle x Average Weight of Cattle (lb) ÷ 1000 (animal unit) x Daily Manure Prod. x Manure Collection Period (days) + Estimated Percent of Bedding in Manure.

https://www.researchgate.net/publication/366928477_Farm_Waste_Management_and_Crop_Production_An_Overview

https://www.researchgate.net/publication/324109627_Evaluation_of_crop_residues_and_manure_production_and_their_geographical_distribution_in_China

https://krishi.icar.gov.in/jspui/bitstream/123456789/71699/1/CROP%20RESIDUE%20WASTE%20OR%20WEALTH.pdf

https://www.researchgate.net/publication/324109627_Evaluation_of_crop_residues_and_manure_production_and_their_geographical_distribution_in_China

https://www.researchgate.net/publication/312922668_Determining_the_number_of_measurements_required_to_estimate_crop_residue_cover_by_different_methods

https://www.researchgate.net/publication/344390146_Analyzing_Disposal_Methods_of_Crop_Residue_Parali

Thanks Prem Baboo for your valuable comment. Actually i want to know, do we have any indirect method by which we can calculate the agriculture/organic waste in a region or country level, other that GIS monitering or NDVI techniques.