I also own farmland that I rent to others, but I only do cash rent. As stated, it's predictable and certain. I have no interest in taking on the incremental risk in terms of price fluctuations, weather extremes, crop failures, deciding when I should sell to make the most money, etc. If I wanted to expose myself to higher risk/return I would just have it custom farmed and take on 100% of the risk.
You do not lose control of your land with a cash lease. You need to be savvy enough to write into the cash rent contract all the cultural/soil conservation/risk management practices that you want followed. It's done all the time and is a good management practice. Prospective renters simply need to consider them in the evaluation of what price they are willing to pay for rent. Off the top of my head, I've got the following clauses:
1) Requirement of annual soil tests, which are also submitted to me for review. Tenant is required to annually apply at minimum the amount of nutrients an average crop removes per Iowa State extension publications. Tenant is required to leave farm with fertility and PH levels equal to where they were when then began farming X years ago. Any deficiencies are fixed and billed to them.
2) Required compliance with all USDA soil conservation guidelines and programs. I review and approve any new conservation plans or crop rotations. They are not allowed to remove any conservation structures such as waterways, terraces, or buffer strips. They are also responsible for maintaining them.
3) I take a first position security interest in all growing crops and crop proceeds. I do not release until I have both the Apr 1 and Sept 1 checks in hand. I had a tenant who had cash flow problems and decided not to pay his second installment. That security interest was worth it's weight in gold. Or in this case, corn.
On a crop share basis, you will also be needing to chip in on operating expenses. Depending on how much land you have, this could require a pretty sizeable cash outlay or operating line of credit. Do you want to go there? Different areas of the country also have different appetites for cash vs sharecrop. Sharecropping is far more predominant in riskier areas of the country - say the say the southern great pains or the southeast compared to the Midwest.
I'd approach this decision like I would an investment. It's all about risk tolerance, expected return, and how much you want to be involved in the process.