Response of Watermelon to Gravel-Mulch and Supplementary Irrigation: Yield, Water Use Efficiency and Root Distribution

A field experiment was conducted to investigate the effect of supplementary irrigation on watermelon (Citullus lanatus) yield, water-use efficiency (WUE) and root distribution in gravel-mulched field in northwest Loess Plateau, China, during 2001 and 2002 growing seasons. The results showed that gravel mulch significantly improved seedling emergence, increased yield and WUE, and alleviated the influence of drought on plant growth. Regardless of gravel mulch application, supplementary irrigation increased watermelon yields, average fruit weight and number of fruit, especially yield increased as the amount of irrigation increased (P<0.05). Generally, WUE of irrigated treatments were higher than that of non-irrigation treatment in gravel-mulched field. The effect of water supply on root distribution was different in two years. In 2001, average root length density (RLD) and root weight density (RWD) whole the soil profile increased. In 2002, however, RLD and RWD decreased as water supply increased. The average RLD and RWD in 2001 were significantly higher than those in 2002. Maybe we can interpret the phenomenon with the theory that there is a need to optimize root distribution (in terms of water relations) and aboveground biomass for a given water supply.The yield may not depend as much on root growth as on the amount of water required at critical stages. A significant effect of soil depth on RLD and RWD were observed in both years, but did not rapidly decrease with depth.

Information Technology Research on Productivity Evaluation of Gravel-mulched Field in Ningxia

The evaluation process of traditional land productivity is relatively complex,and the evaluation indices and results cannot display visually.With the development of geographic information system science,there are more and more studies on the GIS-based land productivity evaluation.GIS system can combine the evaluation model with information system software,realizing the visual display of all the evaluation factors.In this paper,with the development process of GIS-based management information system as references,the management information system for GIS-based gravel-mulched field productivity evaluation was designed and developed by combining with the SI model for gravel-mulched field productivity evaluation.The system was developed under VB environment,integrated with MapInfo,and the evaluation results could be shown visually in the system windows.