Calculating Methods of Forage Crop Water Requirements in Pasture

Most part of forage crop water consumption is water requirements in stockbreeding aspect. The methods of water requirements of forage crop are so important that there are lots of methods of calculating crop water requirements. It's necessary to study the relation of different methods because there are require a large of data. The paper adopts six methods which include evaporation pan method and PM method accounted water requirements of silage maize and elymus dahuricus according to the experiment and meteorological data of water-saving irrigation based in XiLinGuole typical pasture. The research shows that the result of PM method and BC method are larger than PM method, the relative error of Modified PM was larger in the medium-term and advanced growth stage, the relative error of the EP method was larger in the whole growth stage of two forage crop water requirements, the results of PT and MK method were smaller than PM method. The research also shows that the regression equations of Modified Penman method etc. five methods with PM method are good for silage maize and elymus dahuricus water requirements. (c) 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Society for Resources, Environment and Engineering