Effect of Fertilization on Yield of Forage Grass, Nutrient Uptake and Soil Properties under Sudangrass and Ryegrass Rotation Regime

Abstract

Sudangrass and ryegrass rotation is a new type of growth system in Jianghan Plain, which had developed very fast in recent years. So it is highly essential to propose an optimum nutrient management practice for increasing forage grass yield, improving soil fertilization and assuring sustainable development in this new system. Effect of fertilization on yield of forage grass, nutrient uptake and nutrition in soil under Sudangrass and ryegrass rotation regime was studied for two years through the field experiments in Honghu City of Jianghan Plain. The results showed that the application of nitrogen (N), phosphorus (P) and potassium (K) combination obviously improved fresh yield of Sudangrass and ryegrass, with a total forage yield of 162.7 t ha-1 in 2005–2006, which was 312.9%, 26.9%, 17.9% higher than those of PK, NK, NP treatments, respectively. The total forage yield was 114.9 t ha-1 in 2006–2007, and 338.5%, 20.3%, 17.2% higher than those of PK, NK, NP treatments, respectively. Fertilization affected nutrient content of forage grass, and N fertilizer increased N content of grass, and K fertilizer increased K content of grass. NPK combination also promoted nutrient uptake of forage grass, with the higher nutrient uptake than other treatments. The total N, P, K uptake of forage grass was 500 kg ha-1, 91 kg ha-1, 997 kg ha-1 in 2005–2006, and 312 kg ha-1, 56 kg ha-1, 402 kg ha-1 in 2006–2007, respectively. In this rotation, the surplus of N and P2O5 in NPK treatment was the least, compared with that in NP, NK and PK treatments. However, K2O surplus in NPK treatment was the negative. In Sudangrass and ryegrass rotation, organic matter and total nitrogen in soil in all treatments, available phosphorus in soil in NPK, NP, and PK treatments and available potassium in soil in NPK, NK, and PK treatments increased with crop rotation times. But available phosphorus in soil in NK treatment and available potassium in soil in NP treatment slightly degraded, respectively.