DOUBLE CROPPING WITH WINTER CEREALS AND FORAGE SORGHUM IN NEW YORK
Lyons, Sarah Elizabeth
Forage production in New York is primarily for dairy operations and typically includes one main crop per growing season. The most common forage rotations in New York include corn silage (Zea mays L.) and alfalfa (Medicago sativa L.)/grass hay mixtures rotated every three-to-four years. If the ground is left bare over the winter months following corn silage harvest, it enhances risk of soil erosion and nutrient loss. Double cropping with forage winter cereals during the corn silage years can help with soil conservation and nutrient recycling as well as provide additional yield in the spring. Four studies were conducted to determine the nitrogen (N) needs and best time of planting of winter cereals grown for forage in New York. The objectives of the first study (Chapter 1) were to evaluate the impact of fall planting date and N availability on biomass production and N uptake of triticale (x Triticosecale Wittm.). Earlier planted triticale was better able to take up additional N due to increased fall biomass accumulation. The second study (Chapter 2) concluded that N applied to triticale at spring dormancy break was more important for spring yield and forage protein than fall N availability. In Chapter 3, a stepwise method for characterizing yield response to N application was developed and statistical models for determining the most economic rate of N (MERN) based on 62 forage winter cereal N-rate trials were evaluated. The quadratic plateau model was the best option based on both statistical and environmental criteria. The 62 N-rate trials were then used to determine a model for predicting the MERN based on field characteristics and management practices (Chapter 4). Soil drainage, recent manure applications, and planting date were selected as important indicators for the MERN. Because forage winter cereal planting and harvest can overlap with the corn silage growing season, forage sorghum [Sorghum bicolor (L.) Moench] was evaluated in three studies as a potential alternative warm-season silage crop. A sorghum N-rate study with 13 trials determined that yield response to N fertilizer fell into three groups: (1) no response (MERN = 0), (2) no yield plateau (MERN > highest N rate), and (3) a yield plateau between the lowest and highest N rates (Chapter 5). The sorghum required approximately 10 kg N ha-1 per 1 Mg DM ha-1 yield. For seven of these trials, multiple harvests took place to evaluate if sorghum harvest can take place earlier in the fall without reducing yield or nutritive value (Chapter 6). It was concluded that forage sorghum can be harvested at the late flower to early milk stage while maintaining yield and improving fiber digestibility and crude protein. However, if forage sorghum is included in a dairy diet, additional energy supplementation may be needed due to lower starch content at less mature growth stages. A two-year double crop rotation study with forage sorghum and triticale was implemented to determine the optimal harvest time of sorghum and N management of both sorghum and triticale for full-season yield (Chapter 7). Fertilizing sorghum according to N needs and timely harvest supported both sorghum and triticale without having to fertilize the triticale in the spring. Double cropping in New York can be an environmentally and economically beneficial practice if managed properly.
Forage double cropping; Forage production; Forage sorghum; Nitrogen management; Winter cereals; Animal sciences; Agronomy; Soil sciences
Ketterings, Quirine M.
Cherney, Debbie Jeannine; Cherney, Jerome Henry
Ph.D., Animal Science
Doctor of Philosophy
dissertation or thesis