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A study was conducted in the lysimeters and rain-out shelter facility at Shandong Agricultural University to investigate the impact of nitrogen (N) fertilization management practices and irrigation on the losses of N and N use efficiencies of winter wheat in the Huang Huai Hai Plains of northern China. 4 factors, each with two levels, including wheat varieties (SM15 and JM19), irrigation level (well water and deficit water), N fertilizer type (manure fertilizer and urea), N fertilizer rates (90 and 180 kg N ha−1) were applied in duplicate over three wheat growing seasons from 2009 to 2012. Ammonia volatilization rates (AVR) were highest immediately following fertilizer application and declined over 20 days after fertilization, AVR following urea is significantly greater than following manure application and is largely affected by soil NH4+-N concentrations. Cumulative ammonia volatilization (CAV) from urea was approximately three times that from manure. AV accounts for most of N losses and may account for 25% or more of applied N. Leaching losses increased with N fertilization concentration. Pre-winter leaching losses accounted for 69.6–100% of total leaching loss. Total N losses through AV and leaching during the whole wheat growing season were estimated to range from 30 to 60% of applied N. Nitrogen use efficiency (NUE), and N uptake efficiency (NUpE) of the cultivar SM15 is 10.1 and 19.8% greater than JM19 by average under well watered conditions, respectively, but NUE and N utilization efficiency (NUtE) of JM19 were 17.5% and 21.8% higher than SM15 under water stress condition, respectively. In addition, the difference of crop N use efficiency (NUEc) and crop N uptake efficiency (NUpEc) between two varieties was inconsistent to NUE and NUpE. The following results were implicated from this study: (1) ammonia volatilization could be reduced by 66.6% through manure application instead of urea application; (2) reducing fertilizer and irrigation supply during pre-winter stage could be a effective method to reduce N loss in the region; (3) all treatments in this study lead to progressively lower soil fertility except for the 180 kg N ha−1 manure which is able to maintain soil fertility; (4) wheat variety, N fertilizer level, irrigation amount and their interactions have obviously impact on NUE parameters.

Excessive application of N fertilizer contributes substantially to high levels of nitrate (NO3−–N) in surface and groundwater on Northern China. A trial was set up to quantify the fate of N within intensive wheat maize rotation system with a view to improve N and water use efficiencies. This paper describes the construction and testing of a lysimeter facility used for this trial. A 44 lysimeter/rain shelter facility was constructed at Shandong Agricultural University (SDAU). Each lysimeter was equipped with a neutron access tube for soil water monitoring and ceramic solution samplers for soil solutions collection. In order to precisely quantify water input, two rain shelters were used to exclude rainwater. The water balance showed that water outputs and inputs agree within 10% for all lysimeters, and that the average water used being 5% less than the total irrigation water supplied was considered as an acceptable error for such large lysimeters. Wheat grown in these devices was consistently higher than those grown with similar fertilizer management in a field located in Ling Xian due to enhanced soil fertility and irrigation in the devices. The facility was shown to be suitable for investigating water and nutrient balances of the root zone.

We examined the effect of different irrigation and nitrogen (N) fertilizer levels on Zea mays L. (maize) on nitrate-nitrogen (NO3 − -N) leaching under lysimeter conditions. To do so, we used large lysimeters (2.5 m × 2.5 m × 2.0 m deep) at the Maize Technological Innovation Center (MTIC) of the northern China plain (NCP), which is located at Shandong Agriculture University (36°09′N, 117°09′E, 128 m above sea level) in Taian, China. Our study carried out during 3 cropping seasons (2010–2012) where the crop rotation was corn, grown in the summer, followed by wheat in the winter. Nitrogen leaching mainly occurs during maize growth season in maize–wheat rotation system under natural condition. N management of winter wheat has no significant effect on total N of 0–200 cm soil. So, this paper mainly aimed to investigate the summer maize N losses, to provide the data needed to develop best management practices to improve nitrogen use efficiency with the goal to better protect the ecological environment. Our experiment used two maize varieties (Zhongnong 99 [Z99] and Lainong 14 [L14]), two levels of irrigation (525 and 263 mm) during the maize growth period, two fertilizer types (urea and manure), and two N fertilization levels (100 and 200 kg N ha −1 ), with two experimental replicates. We found that the maximum NO 3 − -N leaching of maize from the 200-cm soil layer was 77.22 kg N ha −1 for Z99 and 47.86 kg N ha −1 for L14 (200-kg N ha −1 urea; 525 mm irrigation). The minimum and maximum seasonal average NO 3 − -N concentrations at a depth of 200 cm were 41 and 182 mg l −1 , respectively. Our findings suggest that it may be possible to reduce the amount of NO 3 − -N leaching from the root zone during the growing season by splitting the application of irrigation and fertilizer treatment according to maize growth stage requirements. With the appropriate combination of irrigation and fertilizer management, levels of NO 3 − -N leaching during agricultural practices may be minimized.

Improving grain yield per unit area is needed to meet the growing demand for corn in China where the availability of fertile land is very limited. Roots are vital organs for yield improvement. A field experiment was conducted in 2009 and 2010 to compare the Morphological and physiological characteristics of the root systems of the higher-yielding corn variety DengHai 661 (DH661) and the commonly grown corn variety for northern China ZhengDan 958 (ZD958). The results clearly showed that DH661 consistently yielded higher than ZD958 in both years. The average biomass and grain yield of DH661 were 20.11% and 19.15% higher than those of ZD958. The roots DH661 grow faster than ZD98, it can get the depth to 160–200 cm at VT stage, but the roots of ZD958 get that depth at R3 stage. At the same time, the maximum of root biomass and average root length density (RLD), root actively absorbing area, root TTC reducing capacity after VT stage in both years were 83.06%, 43.30%, 58.10% and 40.38% higher than those of ZD958, respectively. Which can supplying more water and nutrient for the shoot, and improve the LAI, photosynthetic rate (in the later growth stage) and longer duration of high photosynthesis, make the contribution to the shoot growth and grain filling. All the results supporting the hypothesis that greater root systems lead to higher yield.

A field experiment was conducted to investigate the effect of long-term (30-year) fertilizer and organic manure treatments on grain yield, soil chemical properties and some microbiological properties of arable soils in Pingliang, Gansu, China. Six treatments were chosen for this work: unfertilized control (CK), nitrogen fertilizer annually (N), nitrogen and phosphorus (P) fertilizers annually (NP), straw plus N added annually and P fertilizer added every second year (NP + S), farmyard manure added annually (FYM), and farmyard manure plus N and P fertilizers added annually (NP + FYM). Mean winter wheat yields for the 20 years ranged from 1.60 Mg ha − 1 for the CK treatment to 4.62 Mg ha − 1 for the NP+FYM treatment. Maize yields for the 8 years averaged 3.40 and 7.66 Mg ha − 1 in the same treatments. The results showed that there was no interaction between farmyard manure and NP fertilizers. Compared with the CK treatment, the average soil organic carbon (SOC) and total nitrogen (TN) content were 2.0 and 3.1%, 1.9 and 13.3%, 32.7 and 24.5%, 23.0 and 19.4%, and 39.9 and 27.6% larger, respectively, for N, NP, FYM, NP + S and NP + FYM. The N only resulted in not only lowering of pH but also deficient of both P and K in the soil. Soil available K declined rapidly without straw or manure additions. The microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents increased with the application of nitrogen and phosphorus inorganic fertilizers. However, there was greater increase of these parameters when organic manure was applied along with inorganic fertilizers. Organic manure application also increased soil dehydrogenase, alkaline phosphatases, β-glucosidasen and urease activity significantly. The results indicated that long-term additions of organic manure have the most beneficial effects on grain yield and soil quality among the investigated types of fertilization.

SUMMARYField experiments (15 years) were carried out to study the effects of no-tillage (NT) and conventional tillage (CT) management practices on the soil chemical properties, microbial biomass, soil enzymatic activities and winter wheat yield on a cinnamon soil in Shanxi, on the Chinese Loess Plateau. Compared to CT, NT increased soil organic carbon, soil total nitrogen and soil total phosphorus in the 0–100 mm layer by 25, 18 and 7%, respectively. Microbial biomass C and N contents under NT were 41 and 57% greater than under CT on the same layer. In general, higher enzymatic activities were found in the more superficial layers of soil under NT than under CT in the same layer. Winter wheat yield wasc. 20% higher under NT than under CT. These findings have implications for understanding how conservation tillage practices improve soil quality and sustainability in the rainfed dryland farming areas of northern China.

The impact of 14 years of continuous conventional (CT) or no-till (NT) cultivation on surface soil structure and crop yields was examined on a weakly structured silty loam soil at Grafton in N.S.W. The annual soybean yields of the NT treatme between 1981 and 1985 were consistently less than or equal to those resulting from CT with an average of 2.46 t ha−1 and 2.82 t ha−1, respectively, for the two treatments. However, CT was unable to sustain the greater yield, and from 1987 onwards the yields of the NT treatments have typically been greater than those of the CT with averages of 2.14 t ha−1 and 1.67 t ha−1, respectively. During the earlier years of the trial, soil porosity and crop yields were not greatly affected by the different tillage techniques. During later years and at the end of the trial, however, soil porosity and structural stability were greater under NT. Increased soil macroporosity (saturated water content of 0.61 for NT vs 0.40 for CT) and structural stability (dispersed silt + clay contents of 10% for NT vs 30% for CT) under long term no-till cultivation were consistent with higher saturated hydraulic conductivity (189 for NT vs 23 mm h−1 for CT), higher infiltration and lower run-off under rainfall, increased plant available water (12.5% for NT vs 10.5% for CT), water use efficiency, and crop yields. The improvement in soil structure observed under NT is associated with the significant increase in surface soil organic carbon contents (3.37% for NT vs 1.67% for CT) and is shown to be the major contributor to the sustained improvement of crop yields.

Soil health is important for the sustainable development of terrestrial ecosystem. In this paper, we studied the relationship between soil quality and soil microbial properties such as soil microbial biomass and soil enzyme activities in order to illustrate the function of soil microbial properties as bio-indicators of soil health. In this study, microbial biomass C and N contents (Cmic & Nmic). soil enzyme activities, and soil fertility with different fertilizer regimes were carried out based on a 15-year long-term fertilizer experiment in Drab Fluvo-aquic soil in Changping County, Beijing, China. At this site, 7 different treatments were established in 1991. They were in a wheat-maize rotation receiving either no fertilizer (CK). mineral fertilizers (NPK). mineral fertilizers with wheat straw incorporated (NPKW+), mineral fertilizers with incremental wheat straw incorporated (NPKW+), mineral fertilizers plus swine manure (NPKM), mineral fertilizers plus incremental swine manure (NPKM+) or mineral fertilizers with maize straw incorporated (NPKS). In different fertilization treatments Cmic changed from 96.49 to 500.12 mg kg −1 , and Nmic changed from 35.89 to 101.82 mg kg −1 . Compared with CK, the other treatments increased Cmic & Nmic, Cmic/Corg (organic C) ratios, Cmic/Nmic, urease activity, soil organic matter (SOM). soil total nitrogen (STN), and soil total phosphorus (STP). All these properties in treatment with fertilizers input NPKM+ were the highest. Meantime, long-term combined application of mineral fertilizers with organic manure or crop straw could significantly decrease the soil pH in Fluvo-aquic soil (the pH around 8.00 in this experimental soil). Some of soil microbial properties (Cmic/Nmic. urease activity) were positively correlated with soil nutrients. Cmic/Nmic was significantly correlated with SOM and STN contents. The correlation between catalase activity and soil nutrients was not significant. In addition, except of catalase activity, the soil pH in this experiment was negatively correlated with soil microbial properties. In conclusion, soil microbial properties reflect changes of soil quality and thus can be used as bio-indicators of soil health.

Nitrate–N distribution and accumulation down to 200 or 300 cm in the soil profile of different long-term fertilization regimes were studied in 2002 in the China Long-Term Experiments Network (CLTEN) including eight experimental sites where the experiments were started in 1990 or 1991. In this paper we report on the results from five comparable sites (Beijing, Henan, Hunan, Jilin and Xinjiang) representing a wide range of soils, climates and cropping systems some of them with irrigation. At each site, crops (wheat and/or maize) had been grown with no inorganic fertilizer or manure inputs (as control), and with various combinations of N, P or K fertilizers or with NPK plus different levels of manure (M) or straw (S). Fields where N input was from inorganic fertilizers, generally had higher amounts of accumulated NO 3 –N in the soil profile than control or long-term fallowed soils, which indicated that the use of inorganic fertilizer–N in agricultural systems increased the risk of pollution of the environment. Long-term application of fertilizer–N without P (N, NK) resulted in low crop yields and low N uptake by the crops, leading to lower cumulative apparent N recovery (ANR) and higher NO 3 –N content and accumulation in the soil profile. This increased the risk of groundwater contamination by nitrate. When fertilizer–N was applied along with P (NP) or PK (NPK) the crop yields, N uptake by the crops and ANR increased markedly and the NO 3 –N accumulation in the soil profile was much lower than in the N and NK treatments. Adding manure or straw based on equal total N (NPK + M or NPK + S) resulted in similar contents and accumulation of NO 3 –N in the soil profile as in NPK treatment under normal conditions. Increasing the N input levels whether through inorganic fertilizer or manure (NPK + 1.5M or 1.5(NPK + M)) further increased the NO 3 –N accumulation in the soil profile. The data show that potentially 24–82% of applied inorganic fertilizer–N was lost, mostly through ammonia volatilization. It was estimated that a quarter of the N was lost through leaching beyond the root zone.