| Based on the characteristics of agricultural irrigation in arid and semiarid region of china and with the aim of reducing agricultural water use in improving the utilization of regional agricultural water resources,the growth of summer maize was studied under the interaction of the furrow irrigation and straw mulching and the treatment of ridge tillage,.The paper adopts the technical route of combining field experiment,theoretical research,and mathematical analysis.It mainly includes the growth and development of summer maize in different growth stages,the related changes of the distribution of soil moisture in different soil layers and physiological indicators under the combined effects of different water threshold treatment and straw mulch treatment.Furthermore,the effects of water consumption characteristics,grain yield and its components on summer maize are analyzed.The main results obtained were as follows:(1)The effects of different water and straw mulch on the growth and development of summer maize and a rich culture and for irrigation were studied.Because summer maize was in the stage of vegetative growth,the higher the lower limit of water control was the longer the growth period from seedling stage to heading stages.During the stage of from maize heading to maturity which was reproductive growth stage,most of the nutrients and water of its external form have been basically transformed into the internal organs of the maize and exhausted to provide the energy needed to meet the set forth.At that time,the increase of the growth could be inhibited by the lower water control limit(55%FC)and the rate of seedling emergence was not as high as that without mulching.Under the condition of the low water control limit,cover mulching measure was not as good as non-cover treatment,the seedling emergence rate of non-mulch was higher than that of mulch(P<0.05).Although cover mulching measure could effectively promote the increase of maize seedling emergence rate,it was easy to form the phenomenon of sealing pressure when the mountain was too large and it still inhibited the increase of the emergence rate of maize.The Logistic model could be used to describe the process of maize dry matter accumulation.The overall trend of change was that from the emergence of summer maize to the early jointing stage,from the middle jointing stage to the middle filling stage,it increased rapidly,and then slowly increased to the maximum.And the whole process of the above ground dry matter accumulation on the summer maize growth period was divided into three periods and it's showed the slow-fast-slow shaped curve respectively.The duration of dry matter accumulation on the growth period of summer maize under different water control was divided into three stages;the slow increasing period was the biggest.The gradual increasing period was the second,and the fast increasing period was the smallest.In addition,the increase of the lower limit of water content was beneficial to the rapid growth of leaves from jointing stage to heading stage under the control of water content of the field capacity.When the straw mulch increased by 4500 kg/hm~2 under the control of water content of 70%FC and80%FC,the effect of the leaf area was the most remarkable.With the increase of growth period,the plant increased first and then decreased.And the increasing range of plant height decreased gradually when it was in the process of joining and the lower limit of water control,the effect of covering quantity on the plant height of summer maize was not significant when it was in the process of joining,and the lower limit of water control was lower.The bigger the covering quantity was,the more the leaf area was.On the contrary,when the lower limit of water control was gradually increased,the change of cover amount was not obvious to the difference of leaf area during the whole growth period.(2)The effects of different soil water and straw mulch on soil,water distribution and a rich culture and for irrigation of summer maize were studied.Under the same water treatment conditions,the soil moisture content of seedling stage increased first and then decreased with the increase of soil depth and then increased slightly.The soil water content in jointing stage increased at first and then decreased with the increase of soil depth.The soil water content decreased with the increase of soil depth during the testing stage.The soil water content increased with the increase of soil depth during the filling stage.The soil water content of the mature period was outstanding and soil depth increased first and then increased.During the whole growth period,the average soil moisture content increased with the increase of straw mulch.The effect of straw mulch on soil water content in different soil layer was significantly(P<0.05)higher than that of normal treatment.(3)The effects of different water and straw mulching amount on the characteristics of flow irrigation of summer maize were studied.When the lower limit of water content was only 55%FC,the effect of mulching amount on grain-number per spike,100-grain-weight and grain-yield was significant.Under the interaction of water treatment and mulching treatment,Ear-Row-number,100-grain-weight and the grain-yield of the maize were significantly increased.According to the change law of water consumption and grain yield of summer maize in the whole growth period and the relationship between them,the results could be obtained that when the lower limit of water control was under the condition of 70%FC,the highest water-use-efficiency(WUE)and precipitation-use-efficiency(PUE)could be obtained with straw mulch of 7500kg/hm~2 and the consumption of ineffective water could be restrained effectively.The grain-yield and water-use-efficiency could be increased.At the same time,the water consumption coefficient of grain yield per unit of maize was the smallest. |
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