The Response of Corn Grown on Paddy Soil to Flooding and Nitrogen and Phosphorus Fertilization

Abstract

Growth and nitrogen (N) and phosphorus (P) status of a recommended open-pollinated Nakhon Sawan 1 (NS1) and a hybrid CP-DK 888 corn (Zea mays L.) cultivars in response to flooding and N and P fertilization was studied in the glasshouse at Nakhon Sawan Field Crops Research center in 1997. Corn plants were grown on potted paddy soil (Ratchaburi series) and subjected to a short-term flooding of 3 days (d) imposed at 14 days after emergence (DAE), thereafter, excess water was allowed to subside naturally. The corn plants previously flooded were allowed for 14 d (24-38 DAE) to recover from the flooding stress. Either none, or N and P fertilizers equivalent to 62.5 kg of N and P/ha was applied together in liquid just before planting; and then, either none, N,P, or N and P fertilizers was added at the start of a recovery period (24 DAE). Meanwhile, the growth, agronomic characteristics and yield of NS 1 and CP-DK 888 and 6 other commercial hybrids (Hercules 40, Cargill 717, Pioneer 3012, Pacific 47, SW 3601 and NSX 9008) subjected to flooding at 14 and 28 DAE (2 days of flooding and excess water was left to subside naturally) was studied in the field with the same soil series at excess water was left to subside naturally) was studied in the field with the same soil series at excess water was left to subside naturally) was studied in the field with the same soil series at Chainat Field Crops Research Center. In a pot trial, flooding stress (14-24 DAE) resulted in a more reduction in growth (relative growth rates of dry mass of plant parts and leaf areas) of NS 1 than that of CP-DK 888 and a decrease in N and P concentrations in plant parts of both cultivars. However, NS1 did better than CP-DK 888 during recovery from the flooding stress. Even though N and P fertilization at planting led to an increase in N and P concentrations in plant parts at the end of flooding, it had no marked effects on growth of both cultivrs during subjected to flooding stress. Whereas, N and P fertilization at the start of a recovery period, and those at planting as well, not only increased the N and P concentrations in plant parts but also the growth of corn plants during recovery from the flooding stress. Flooding markedly delayed days to anthesis 1-2 and extended anthesis-silking intervals (AS) for 2-5 d (except CP-DK 888) and reduced plant heights, no. of grains/ear and yields of 8 corn cultivars grown in the field. The reduction in grain yields due to flooding stress was least (52%) in Pioneer 3012 and Cargill 717, and was most (94%) in NS 1 and SW 3601. The yields of corn cultivars used to subjected to flooding were positively linearly correlated with those yields under well-drained conditions (r=0.87**).