Effects Of Straw Mulching Amount And Fertilize Amount On Soil Nutrients And Physiology And Growth Characteristics Of Maize In Black Soil Region

In order to reveal the response mechanism of soil nutrients,corn growth physiological indexes,yield and its components to straw mulching and fertilization in the black soil region of Northeast China,corn fields in Heilongjiang Province were taken as the research object under the background of rainfed agriculture.Conventional fertilization without mulching（CK）,0.5 times straw mulching 80%fertilizer rate（LM₁）,0.5 times straw mulching 100%fertilizer rate（CM₁）,0.5times straw mulching 120%fertilizer rate（HM₁）,1.0 times straw mulching 80%fertilizer rate（LM₂）,1.0 times straw mulching 100%fertilizer rate（CM₂）,1.0 times straw mulching Based on the measured soil nutrients,maize growth physiological indexes and yield components,10treatments including straw mulching 120%fertilizer rate（HM₂）,1.5 times straw mulching 80%fertilizer rate（LM₃）,1.5 times straw mulching 100%fertilizer rate（CM₃）,1.5 times straw mulching 120%fertilizer rate（HM₃）,Research and analysis of different amount of straw mulching and fertilizer rate under the condition of corn maize growth and physiological characteristics of the change rule of soil nutrient changes dynamically,reveal different straw mulching quantity and fertilizer application on soil nutrients,maize growth,physiological index and effect mechanism of maize yield,put forward suitable the straw mulching and fertilizer combination mode of the northeast black soil area,It provides theoretical basis and scientific guidance for the popularization and application of straw mulching technology in black soil area.The main conclusions are as follows:（1）Soil nutrient content increased with the increase of fertilizer application rate,and the effect of fertilizer application on soil nutrient decreased with the advance of growth period.Soil nutrient content decreased with the deepening of soil depth.The nitrate content in 0～60 cm soil layer decreased with the progress of growth period,and decreased first and then increased with the deepening of soil depth.The nitrate content in each soil depth at seedling stage increased with the increase of fertilizer application rate,but there was no obvious trend in other growth periods.The effect of straw mulch amount on the nitrate content in each soil layer had no regular trend.The ammonium nitrogen content in 0～60 cm soil layer increased with the increase of fertilizer application rate,except for 100%fertilization+1.0 times straw mulch treatment.The ammonium nitrogen content in 0～60 cm soil layer increased first and then decreased with the increase of straw mulch amount,except for some treatments.The total nitrogen content in the 0～20 cm soil layer decreased first and then increased with the growth period,but there was no obvious change trend in the 20～60 cm soil layer.The total nitrogen content in the soil decreased with the depth of the soil layer,but increased with the increase of fertilizer application rate.The effect of straw mulching on the total nitrogen content in the soil layer showed no regular trend.The available P content in 0～60 cm soil layer decreased first and then increased with the progress of growth period,decreased with the deepening of soil depth,increased with the increase of fertilizer application rate,and increased first and then decreased with the increase of straw mulch amount.The total P content in the 0～60 cm soil layer had no obvious trend with the growth period,the total P content in the0～40 cm soil layer increased with the increase of fertilizer application rate,and the total P content in the 40～60 cm soil layer had no obvious trend,and showed no regular trend with the straw mulch amount.The available K content in the 0～60 cm soil layer decreased first and then increased with the growth period.The available K content in the 0～40 cm soil layer increased with the increase of straw mulching amount and fertilizer application rate,but there was no obvious change in the40～60 cm soil layer.（2）The net photosynthetic rate of maize functional leaves was the same as that of stomatal conductance.It increased first and then decreased with the growth period,and reached the highest at the heading stage.The net photosynthetic rate at the seedling stage increased with the increase of straw coverage and fertilizer application,and the stomatal conductance increased with the increase of straw coverage and fertilizer application during the whole growth period;The intercellular CO₂ concentration decreased with the increase of fertilizer application,and the intercellular CO₂ concentration was the lowest in 1.0 times straw mulching at each growth stage;The effect of fertilization amount at Seedling Stage on plant height is the main factor.The plant height of 80%fertilization treatment group is lower than that of the control.Except for the seedling stage,the plant height of CM₂ group at each growth stage is the highest.The plant height of CM₁,CM₂ and CM₃ treatment at each growth stage is significantly higher than that of CK treatment by 3.4%-19.0%,17.5%-56.9%and 4.3%-33.8%respectively;The overall change trend of chlorophyll was the same as that of net photosynthetic rate,showing a change trend of first increasing and then decreasing;Compared with the control group,straw mulching could increase the corn yield under the same amount of fertilizer,showing a trend of first increasing and then decreasing with the amount of straw mulching;There was no obvious change trend in 100 grain weight and grain number per ear.（3）The comprehensive effect evaluation of soil nutrient and crop physiological growth characteristics under different straw mulching and fertilizer application rates showed that the comprehensive benefit value of 120%straw mulching treatment with 1.0 times fertilizer application rate was the highest,and the comprehensive benefit value of 100%straw mulching treatment with 1.0 times fertilizer application rate was the second.There was no significant difference in the comprehensive benefit value between the above two treatments.