Is the produce irrigated by rainwater in our present time - with its accompanying hardship and cost due to automatic machinery and chemical fertilizers - to be measured against that which is irrigated by manual irrigation (nadh) such that one-twentieth is extracted from it, or is it not to be measured as such, resulting in the extraction of one-tenth?

The tithe is obligatory on what is irrigated by rainwater, based on the Prophet's ﷺ saying: "On what is irrigated by the sky and springs, or what is unirrigated, there is a tithe (one-tenth); and on what is irrigated by effort (like camels drawing water), there is half a tithe (one-twentieth)." Thus, zakat is linked to irrigation. What is irrigated by rainwater, springs, or rivers requires the full tithe, while what is irrigated by machinery or involves effort requires half a tithe.