Effects of water management and mulching on weed control and rice grain yield under water saving irrigation model.

摘要

A field experiment was conducted to study the effect of mulching, water and weeds on rice cultivars. Water is an essential input in rice production. China faces severe problems caused by increasing demand on its limited water resources. Since agriculture is the main user of fresh water in China, the use of water-saving irrigation methods can help save water, which can be used in other sectors of the economy. In conventional paddy rice production, one of the most important irrigated crops, a significant amount of irrigation water is lost due to percolation and evaporation. A new irrigation model called Rain-Catching and Controlled Irrigation (RCCI) has been developed as a viable water-saving technology in the production of paddy rice. Preliminary research into this model has shown that RCCI can save not only water but also labor without reduction in grain yield compared with traditional Continuous Flooding Irrigation (CFI). In this paper, the performance of RCCI model has been analyzed under mulching and weedy conditions in Jiangsu province. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications and six treatments. The three replications comprised three water management regimes: high dry high flooding (T3) treatment, high dry low flooding (T2) treatment, and shallow and frequent irrigation (T1) treatment. RCCI model was adopted in T3 and T2 while CFI was adopted in T1 as a control. Of the six treatments, three were under mulching conditions and three were under weedy conditions. The rice variety used was Nanjing 44. It was observed that weed density and dry weight were significantly influenced by the amount of irrigation water in all the mulching and weedy plots. Under mulching conditions the mean maximum grain yield was 5042.4 kg ha-1 in T2, where 10 numbers of irrigations were applied, while the yield in T3 was 4342 kg ha-1 with 8 irrigations and in T1 was 4033.4 kg ha-1 with 13 irrigations. Under weedy conditions the mean maximum was 1273.6 kg ha-1 in T1, where 15 numbers of irrigations were applied while the minimum was 903 kg ha-1 in T3 with 10 irrigations and the yield in T2 with 11 numbers of irrigations was 1166.8 kg ha-1, showing a reduction in mean maximum and minimum grain yield of 74.6 and 82.1%, respectively. The treatments influenced the yield and number of irrigations required. Considering yield and number of irrigations, RCCI model produced better results than CFI.