| Excessive application and inefficient use of nitrogen fertilizer haved caused a series of ecological and environmental problems,which threatened agricultural ecological security and sustainable development.Moderately reducing the amount of nitrogen fertilizer inputs,scientific allocation of fertilizer and other measures to reduce nitrogen losses,improve nitrogen use efficiency,effective prevention and control of agricultural non-point source pollution has become an urgent need for the sustainable development of agriculture and ecological environment construction in China.This study was carried out under the rotation system of winter wheat and summer maize,the application of humic acid to reduce the amount of nitrogen fertilizer in nitrogen fertilizer operation mode,which explored the effects of the single application of PKfertilizer(T1),conventional fertilization that is a single application of NPK(T2),single humic acid(T3),conventional fertilization+ humic acid(T4),conventional fertilization and nitrogen reduction15%+humic acid(T5)and conventional fertilization and nitrogen reduction 30%+ humic acid(T6)6 fertilization treatments on soil physical and chemical properties,physiological characteristics of crops,nitrogen uptake and utilization,crop yield and nitrogen gain effect in two main types of ecological regions(fluro aquic region of Northern Henan and yellow cinnamon soil region of Southern Henan)in Henan Province.The aim of this study was revealed the response mechanism of crops to reducing nitrogen and humic acid in winter wheat and summer maize rotation.The main results of are as follows:1.Combined application of humic acid and nitrogen fertilizers could effectively improve the physical and chemical properties of soil.The Combined application of humic acid and Conventional fertilization and nitrogen application of 15%(T5)treatment effect is the best.In fluro aquic region of Northern Henan and yellow cinnamon soil region of Southern Henan,the soil bulk density of T5 treatment was the lowest,which was significantly lower than that of other treatments(3.67%~8.88% and 0.73%~4.91%,respectively)(P<0.05);However,the soil organic matter content,nitrogen content,available phosphorus content and available potassium content of T5 treatment were the highest.Compared with conventional fertilization,soil organic matter increased by 0.44%,4.58%,soil total nitrogen and alkali-hydrolyzable nitrogen content increased significantly by 5.41% and 2.16%,21.76% and 9.82%(P<0.05),soil available phosphorus increased by 4.66%,2.68%,and the content of soil available potassium increased by 1.65%,1.84%.The pH value of T1 treatment was the highest in topsoil soil in fluro aquic region of Northern Henan,however,T5 treatment was the lowest,which was 8.98% lower than T1 treatment(P<0.05).While there was no significant difference in pH value between different treatments in yellow cinnamon soil region of Southern Henan(P>0.05).2.Combined application of humic acid and nitrogen fertilizers could effectively improve the photosynthetic characteristics of winter wheat and summer maize.The Combined application of humic acid and Conventional fertilization and nitrogen application of 15%(T5)treatment effect is the best.In fluro aquic region of Northern Henan and yellow cinnamon soil region of Southern Henan,the trend of SPAD,net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of winter wheat and summer maize were basically the same,which were increased first and then decreased with the growth period,while the intercellular CO2 concentration(Ci)was completely opposite.The SPAD values,Pn,Gs and Tr of winter wheat and summer maize leaves of T5 treatment were the highest,while Ci was the lowest,compared with conventional fertilization,the SPAD value of winter wheat leaves increased by 5.77%~32.19% and 4.84%~61.34%,Pn of winter wheat leaves increased by 12.08%~21.66% and 2.21%~51.02%,Gs of winter wheat leaves increased by 8.78%~14.97% and 16.57%~49.70%,Tr of winter wheat leaves increased by 10.53%~26.98% and 12.37%~27.00%,while Ci of winter wheat leaves decreased by 8.32%~24.02% and 8.32%~30.93%;the SPAD value of summer maize leaves increased by4.52%~18.98% and 6.48%~16.58%,Pn of summer maize leaves increased by 12.08%~21.66% and 12.10%~22.16%,Gs of summer maize leaves increased by 14.29%~34.97% and 14.38%~46.06%,Tr of summer maize leaves increased by 14.87%~27.02% and 14.88%~73.28%,while Ci of summer maize leaves decreased by 16.10%~40.32% and 24.23% ~40.33%.3.Combined application of humic acid and N fertilizers effectively promoted the uptake and accumulation of nitrogen in various organs of winter wheat and summer maize.Among treatments,the treatment of conventional fertilization with 15% less N plus humic acid treatment had the best effects.Compared with conventional fertilization,Grain N content,grain N accumulation and above-ground total N accumulation in winter wheat of T5 treatment in fluro aquic region of Northern Henan and yellow cinnamon soil region of Southern Henan increased significantly by T5 24.24%,29.12%,21.96% and 23.02%,29.12%,18.92%(P<0.05).In fluroaquic region of Northern Henan and yellow cinnamon soil region of Southern Henan,for grain N content,grain N accumulation and above-ground total N accumulation of summer maize,T4 treatment was significantly higher than that of T1 and T3(P<0.05),compared with T2 treatment,T4 treatment increased respectively by 1.79% and 0.98%,14.69% and 5.54%,9.14%,and 6.11%,but the difference was not significant(P>0.05).Among combined application of humic acid and different N fertilizers treatments,the above-ground total N accumulation of T5 treatment was the highest,which was significantly higher than T4 and T6 treatment 1.43%,21.04% and 2.56%,18.87% in two ecological areas.4.The effects of humic acid and nitrogen fertilizer on grain yield,nitrogen use efficiency and economic benefits to winter wheat and summer maize were significantly improved,and the effect of T5 treatment was the best.In fluro aquic region of Northern Henan and yellow cinnamon soil region of Southern Henan,,the yield of winter wheat of T4 was increased by 6.09%(P<0.05)and 0.15%(P>0.05),and the yield of summer maize was increased by 10.74%(P<0.05),(P>0.05)and 4.55%(P<0.05),respectively,compared with T2.The yield of winter wheat treated with T5 was significantly increased by 5.29%,6.86% and 4.80%,3.68%,respectively,compared with T4 and T6 in the two ecological zones.In fluro aquic region of Northern Henan,summer maize yield in T5 treatment was higher than that of T4 and T6 by 1.94%(P>0.05)and 25.32%(P<0.05),while in the south area of yellow cinnamon soils.The yield of summer maize treated with T5 was increased by 3.94% and 22.25%,significant difference(P<0.05),compared with T4 and T6.In the two ecological regions,T5 treatment was the highest on the nitrogen use efficiency of winter wheat,and T5 treatment was significantly increased by 82.34%,51.93%,15.89%,and 67.45%,60.79% and 9.27%,respectively,compared with T2 and T4 and T6 and T2 and T4 treatment significantly different(P<0.05).Compared with T2 treatment,the nitrogen use efficiency of summer maize under T5 treatment increased significantly by 59.86% and 52.00%(P<0.05)in two ecological zones,respectively and was significantly higher than others.In two ecological zones the economic benefit of the winter wheat-summer maize rotation system was the highest treated with T5,which was higher than that of the other fertilization treatments(7.15%~64.98% and 7.23%~64.96%,respectively),and the difference was significant(P<0.05). |
PDF Full Text Request