Effects Of Irrigation, Fertilization And Mulching On Maize Growth And Nitrogen Absorption In The Loess Plateau

The main factors restricted the Loess Plateau agricultural development was short ofwater resources, serious soil erosion and soil fertility. Soil moisture and fertility influenceeach other, soil moisture was the medium and carrier for soil fertility dissolution andmigration, and the fertility migration amount, migration rate and migration depth wereaffected by soil moisture content; the fertility deficiency affects on soil moisture absorptionand utilization. In order to study the influence of soil moisture and fertility on crop yield andsoil environment research, which was an effective way in the agricultural sustainabledevelopment and a basic measure for food security and environmental protection. Thepurpose of this study was to investigate the effect of irrigation, nitrogen fertilization andmulching on maize growth, soil environment, nitrogen absorption and grain yield in pot andfield experiments, and to provide theoretical and experimental basis for field management.The main conclusions were as follows:(1) There were significant differences on maize plant height and leaf area amongirrigation and fertilization amount (P<0.01). Plant height and leaf area were positivelycorrelated with irrigation amount. The plant height decreased with the increase of nitrogenfertilization in seedling and jointing stage. The growth of root synchronized withaboveground biomass, and the dry matter accumulation increased with the increase ofirrigation; the root-shoot ratio declined with the increase of growth period. The nitrogenfertilization significantly increased the chlorophyll content, and the drought-resistant abilitywas also increased.(2) The root and stem-leaf nitrogen content gradually declined along with theadvancement of growth period, which positively related to the nitrogen application, andnegatively related to the irrigation water. Nitrogen nutrient in root gradually shifted to stemand leaf, and stem-leaf N distribution in mature accounted for more than90%. The nitrogenaccumulation rate in root and stem-leaf was on the trend of quickly increasing first and thengradually declining. The stem-leaf nitrogen accumulation was about nine times of root in the mature stage. Water and nitrogen use efficiency was significantly influenced by irrigation andfertilization amount. Water use efficiency increased with the increase of irrigation amount,which was the largest in low nitrogen treatment (3.08kg·m-3). Nitrogen use efficiencyincreased with the increase of irrigation amount, and decreased with the increase of nitrogenapplication. Nitrogen use efficiency was the largest (65.44%) in high water and low nitrogentreatment.(3) Plant height and leaf area positively related to the irrigation and nitrogen amount,and the daily leaf area in jointing stage was among137.50to179.03cm2·plant-1. There wasan extremely significant difference on yield for irrigation, and a significant difference forinteraction between water and fertilization. The variation trend of crop growth rate rises firstand then falls. Yield and biological yield positively correlated to irrigation and fertilizeramount. Yield was the largest (7923.02kg·ha-1) in high water and high nitrogen treatment,which was1.72times of check treatment.(4) The influence of fertilization and irrigation on soil water content was obvious. Thegreater the fertilizer amount, the greater the amplitude of variation of soil water content.Irrigation water productivity and water use efficiency were positively correlated withfertilizing amount, which were negatively correlated with irrigation amount. The soilnitrate-N content was reduced gradually with the increase of soil depth in seedling andjointing stage. There was significant difference of soil nitrate-N content among fertilizationtreatments. The soil ammonium-N content in0to30cm was largest than others, and the soilammonium-N content was decreased rapidly in30cm, and the results showed that smallvariation of soil ammonium-N content from50to100cm.(5) The soil temperature of the10-cm mulching treatment was significantly higher thanthe no-mulching treatment, and the average soil temperature of the mulching treatmentincreased2.3°C before July and nearly1.2°C after July. The soil water content in themulching treatment was significantly higher than the no-mulching treatment at0-60cm; thelevel was significantly reduced at140-200cm. In mature period, there was no significantdifference of soil water content of different cultivation. The trend for soil nitrate-N contentdistribution revealed symmetrical shapes along the center of furrows, and the standardsymmetrical distribution was reduced gradually along with the soil depth increasing underplastic film mulching conditions. The soil nitrate-N content with basal fertilizer was1.65times higher than with no fertilizer at36days after sowing. The soil nitrate-N content wasreduced from30.77to48.67mg·kg-1in the topsoil after58days. Our findings indicate thatplastic film mulching with basal fertilizer increased maize yield23.42%to83.23%.(6) We recommend the first farming management technology:(a) the irrigation amount is 112.5mm, which irrigation in seedling stage is25mm, jointing stage is50mm, and fillingstage is37.5mm and mature period with no irrigation, respectively;(b) fertilization treatmentare80kg pure N and160kg P2O5per ha. We recommend the second farming managementtechnology:(a) film mulching;(b) the irrigation amount is50mm, which irrigation in jointingstage is25mm, and in filling stage is25mm;(c) fertilization treatment are80kg pure N and80kg P2O5per ha as basal application. We recommend the third farming managementtechnology:(a) film mulching;(b) basal fertilizer is80kg pure N and80kg P2O5per ha,topdressing fertilizer is80kg pure N per ha.