Effects Of Irrigation And Straw Mulching On Biomass And Quality Of Grain-forage Maize

Considering the problem of insufficient water resources in agricultural production and lowwater use efficiency in the arid and semiarid areas of northwest China, effects of irrigation andstraw mulching on biomass and quality of grain-forage maize was conducted in teaching farm ofGan Su agricultural technical vocational college in Yu Zhong County in the city of Lan Zhou in2010, there are six irrigation treatments: saving water by40%with/without straw mulchingW1/W1F, saving water by20%with/without straw mulching W2/W2F, control group ofsufficient irrigation with/without straw mulching W3/W3F. The results showed that:1) The effects of grain-forage maize leaf area, dry matter, plant height on irrigationconditions were different. Each index is significantly higher in W3than W1, but there is noobvious difference between W2and W3treatment. The stem diameter in W2treatment is thehighest in different water treatments，which increased33.3%～45.5%compared with W1treatment and improved3.25%～16.6%compared with W3treatment. Under the same irrigationconditions，each growth index has improved with straw mulching. The grain yield increased11.3%in W2treatment compared with W3treatment. But the straw yield showed a oppositeconsequence，reduced only1.8%.2) Under the same mulching conditions, soil water content of grain-forage maize in depth of40cm showed that W1were5.59%and9.7%lower than W2and W3; W3is only3.8%morethan W2, the difference between W2and W3is not obvious, The overall performance wasW3>W2>W1. Compared soil water content in treatments with mulching and without mulching,we can find: W1F>W1; W2F>W2; W3F>W3, soil water content with mulching treatments are1.2%,2.04%,0.8%more than not mulching ones.3) The straw mulching have obviously effects on soil temperature. Straw mulching in depthof5cm and10cm could reduce or increase soil temperature at day or night obviously, but fordepth of15-20cm, straw mulching had no remarkable influence on soil temperature. The soiltemperature decreased with soil depth in all treatments, and decreased gradually with theincreasing irrigation amount.4) With the decrease of irrigation，the distribution of root biomass shifted to greater depth,but the root biomass distribution of W2treatment is more deeper than W1and W3treatment.Different irrigation amounts have more obvious effects on root length, root volume, root surfacearea in topsoil than that in greater depth. Under the same irrigation conditions, mulchingtreatments make for the growth and development of grain-forage maize root, the total rootbiomass of each mulching treatment increased10.5%、8.9%、4.1%.5) Grain yield of grain-forage maize is the highest in mature period, but the forage nutritive values of straw is the best at the end of the milking or at the early waxen stage. So theharvest time is a key factor that influenced the grain and straw yield of grain-forage maize.According to the need of forage and grain in local farmers, the harvest time could be advanced ordelayed.6) In the growing processes, crude protein and crude ash content of grain-forage maize leaf,stem and sheath are showing a reducing trend, and the content of crude fiber and crude fatshowed the opposite trend. Overall, different nutritive value content of grain-forage maize in W1treatment was restricted. There is no remarkable difference between W2and W3, but W2showedsome degree of increase and improving.Under the same irrigation conditions, nutritive qualitycontent in mulching treatments has different degree of improvement compared with no mulchingtreatments. So, the nutritive quality content of the grain-forage maize can be improved throughirritation and mulching treatments.