Comparison of the Function of Different Water-Saving Rice Cultivation Systems in the Seasonal-Drought Hilly Region of Southern China

Abstract

ABSTRACT This study examines the material flow, energy flow, value flow, and ecological environmental benefits of water-saving rice cultivation systems. The results showed that the net production and economical production in the Results his only two types of water-saving rice cultivation systems were 3.10 × 105 to 3.78 × 105 MJ (ha·yr)−1 and 1.77 × 105 to 1.98 × 105 MJ (ha·yr)−1, respectively. The major input of energy was from fertilizers, which were 0.59 × 105 to 0.97 × 105 MJ (ha·yr)−1. The output-input ratios of energy and light utilization efficiency of rice fields were 3.22 to 6.45:1 and 0.64 to 0.78, respectively. The net monetary values were $484 to $1166 (ha·yr)−1, and the cost-benefit ratios were 0.34 to 0.88. Higher energy conversion efficiency, light utilization efficiency, and economic efficiency were found in the water-saving irrigation double-cropping rice cultivation system and water-saving rice cultivation system of rice and rape rotation. However, the lower energy conversion efficiency and economic efficiency took place in water-saving rice cultivation system of flood-drought cultivation. The water-saving rice cultivation systems had a higher integral benefit than did the local rice cultivation system, and could significantly save water and decrease the application of fertilizer and pesticide, allowing control of agriculture non-point resource pollution.