Preharvest Management Harvest-ready rice in California is a mixture of mature and immature kernels that present a harvesting and handling challenge to maximize the percent of whole kernels. A single panicle of rice flowers from the top downward to its base, and from the tip of the branches inward, normally taking 7 to 10 days to complete the process. In addition, grain size and rate of filling decrease from the upper part to the lower part of the panicle, and generally very early and early varieties have more variability than intermediate and late varieties. Recognizing that variability exists can help in machinery adjustment. Many studies have shown that head rice generally decreases as grain moisture content at harvest decreases.
Every field has some dry kernels, which are subject to damage from rehydration.
This relationship of moisture to milling yield gives growers a degree of control over head rice by timing their harvest according to moisture content. Growers should therefore expedite handling between field and drier to reduce head rice losses. Because wetter rice is more expensive to dry, growers frequently harvest rice at a moisture content lower than what is best for quality. Since some dryers may decline to receive very wet rice during the busiest part of the harvest season, the decision of when to harvest may not always be up to the grower. Milling quality in recent years has been fairly good so the system appears to be working.