8 m groundwater table(GWT) under 90 mm and 45 mm irrigation amount per time was investigated through disturbed soil columns by using tracer Br-in lab.

The result shows that the quality and the totall economical index of treatment with first irrigation at 25d and secondly irrigation at 50d after transplant,nitrogen dosage of 60kg per hectare are best.

Yield was increased by rising number of irrigation times.

In order to clarify the effects of irrigation frequency and potassium fertilization on population dry matter production and grain yield formation, two field experiments was carried out during 2006-2007 in Gaocheng County and 2007-2008 in Baoding with locally commercial winter wheat cultivar Henong 822 and Shixin 616 respectively.

The experiments during the two winter wheat growing seasons were arranged as split plot arrangement, with irrigation frequency as main plots ( including 0, 1, 2 and 3 times during the growing period on the basis of suitable pre-sowing soil moisture, expressed as W0, W1, W2 and W3, respectively ), and nitrogen application amounts as split plots ( including N 0, 112.

[Objective] This study intended to study whether irrigation frequency,fertilizing quantity and colonization density were the major factors which caused cracking prematurely in spring cabbage leafy head.

Effect of different irrigation quantity on bromide transport in soil;

The quadratic regression orthogonal design was used the maize pot test to establish the mathematical models between irrigation quantity and plant height,dry weights of stem,roots and plant under different soil moisture for getting the optimum soil moisture and irrigation quantity under the maximum parameters of plant height and dry weights of plant,stem and root.

This paper studied the effects of irrigation quantity and periodicity on impatiens growth in greenhouse by the measure of orthogonal test with modes of trickle, micro-sprinkling and manual irrigations, and achieved t.