Water in desert areas is the most important factor limiting plant growth. Innatural conditions, the availability of moisture and nitrogen is dependent on thedynamic changes in the environment, the fluctuation of precipitation and resourcepulse greatly impact the germination, individual growth and reproduction of differentdesert plants. Spring annual plants, also called ephemerals, and summer annual plantshave significant different water and nutrient use efficiency. Therefore, we infer thatthe seasonal variation of water and N availability will change the growth dynamicsand interspecific relationship of these two different life forms of plants, and it willalso affect their relationship in community phenology. This study examined anephemeral (Malcolmia Africana) plant’s characteristics in terms of floweringphenology, individual growth, biomass distribution and interspecific competition withan annual grass specie known as Descuminia Sophia with a long life cycle response toseasonal nitrogen availability. Plants received the same amount of water in threedifferent patterns according to the real water and N deposition in study area. The mainresults are as follows:Nitrogen application patterns have a significant effect on the process of M.african’s flowering phenology with a typical single-peak curve under the even modeland spring-dominated model, and a trend of two-peak curve under summer-dominatedmodel. The final plant height of M. African under spring-dominated model is thehighest in three treatments in individual growth.Different water application patterns significantly changed the flowering curve ofthe flowering grain. Compared to the average model of water addition, the index andthe single-peak water patterns make the flowering peak in advance. Compared to theindividual growth environment, under the competition with D. sophia, the ratio offlowering of M. africana changed a lot in different time. The flowering of M. Africanaunder the average water pattern is more dispersed in individual growth environmentbut more concentrated in intergrowth environment.The competition for water is more intense in individual growth environment thanthat in intergrowth environment. The M. africana is sensitive to precipitation and itcan use the short-term sufficient water to grow but with lower drought resilience thanD. sophia with the longer life history. Under the background of increasing spatial-temporal distribution of precipitation in arid area, the amount and pattern ofprecipitation variability will make an important effect on desert plants’ growth,phenology and even community composition
