Chemical fertilizer reduction and soil fertility maintenance in rice-fish coculture system

Abstract

In the long run, whether the use of chemical fertilizers could be reduced and soil fertility could be maintained through rice-fish coculture is less well known. At the pilot site of the rice-fish coculture system, which is one of the five "globally important agricultural heritage systems" (GIAHS), we conducted a 4-year study to compare fertilizer use, rice yield, and soil fertility in rice-fish coculture and rice monoculture. Based on the survey data from 21 villages, rice yield did not differ between rice monoculture and rice-fish coculture, but less chemical fertilizers were used in rice-fish coculture than in rice monoculture. Survey data from 145 farms also showed that rice-fish coculture farms with high input of feed for fish used less chemical fertilizers for rice production than farms with low input of feed for fish. In the 4-year field experiment, although less fertilizer was used in rice-fish coculture, rice yield, soil organic matter, soil total nitrogen, and soluble phosphorus did not differ between rice-fish coculture and rice monoculture. Our results suggest that rice-fish coculture can reduce chemical fertilizers application, enhance land productivity, and maintain soil fertility. Our results also suggest that rice-fish coculture could reduce the risk of non-point source pollution by reducing the input of chemical fertilizers.

Ecological mechanisms underlying the sustainability of the agricultural heritage rice–fish coculture system

“…During our study, paired farmer fields in the survey and plots in field experiment 1 did not change in rice variety, irrigation scheme, and fertilization level (20,23) (Table S1). In addition, weather (temperature, precipitation, and relative humidity) during the rice growing seasons did not vary widely over the 6 y (Fig.…”

“…In the last decade, high-yielding hybrid rice varieties have been dominant (20). The rice-fish coculture is considered a sustainable form of agriculture because it maximizes the benefits of scarce land and water resources by using relatively few chemical inputs, by producing both carbohydrate and protein products, and by conserving biodiversity (20)(21)(22)(23)(24). Despite other changes resulting from rapid development over the last 30 y in China, farmers continue to practice rice-fish coculture, in part because this system is an important component of traditional culture and local customs (e.g., rice-fish festivals) (21).…”

Effect of introducing frogs and fish on soil phosphorus availability dynamics and their relationship with rice yield in paddy fields

“…In our 9-year field experiment, the average rice yields increased by 22.1% in the RFF farming system and 6.8% in the RF farming system compared to the yields of the RO farming system. However, a 6-year survey by Xie 26 showed that the rice yields between RF and RO farming systems did not differ. This is probably due to the application of pesticides to and large amounts of manure or chemical fertilizer in the RF and RO farming systems that were surveyed in Xie's study.…”

Research Progress in the Conservation and Development of China-Nationally Important Agricultural Heritage Systems (China-NIAHS)

“…Research also indicates that these interactions control pests and diseases of rice plants [15][16][17][18], improve soil fertility [19], increase soil microbial activity [20], and change growth traits like root shape and lodging resistance [21]. Rice yield is increased, and the application of chemical fertilizers and pesticides is reduced by up to 30% [22]. Additionally, the ecological benefits increase as the diversity of field fish increases [23].…”