Wild rice (Zizania aquatica L.) is a newly cultivated crop and its nutrient requirements are not well defined. To develop a sound fertilization program, a better understanding of the growth, nutrient uptake and distribution in the plant is essential. The purpose of this research was to investigate the dry matter, N, P, and K accumulation, and distribution pattern of wild rice throughout its growth cycle. This study utilized a portion of an NP factorial experiment conducted with K2 cultivar on peat soil (Terric Borohemist) in a grower's paddy in northcentral Minnesota. Plant samples were collected from six 3.7- ✕ 3.7-m areas receiving 40, 19.7, and 55.7 kg/ha of N, P, and K, respectively. Dry matter accumulation and nutrient element concentration in various above-ground plant parts wre determined at 10 growth stages. At the jointing stage, the second leaf was separated and analyzed for N, P, and K.
Although N, P, and K uptake preceded dry matter production, the accumulation patterns were similar. Accumulation rates were slow during the vegetative development phase, e.g., first 50 days after emergence. Following the jointing stage, during a 30-day period of rapid growth, the plant accumulated over half of its dry matter and plant nutrients. Accumulation of plant nutrients continued at a relatively rapid rate until maturity. The effectiveness of topdress N application at jointing is partially explained by data indicating that wild rice accumulated 70% of its total N during flowering and grain formation. The second leaf at jointing contained 3.83% N, 0.55% P, and 3.73% K.
A single plant produced 30 g of total dry matter and took up 300 mg N, 110 mg P, and 740 mg of K. The grain contained 38, 22, and 3% of the total amount of N, P, and K, respectively, taken up by the plant. Nearly 85% of total K accumulated in stems. In this study, wild rice produced nearly 11,800 kg/ha of dry matter and contained 120, 40, and 290 kg/ha of N, P, and K, respectively. A major portion of nutrient elements was supplied by the soil.