锌与氮磷肥配合喷施对冬小麦锌累积及锌肥利用率的影响

【目的】在不同栽培模式及施氮量条件下,研究锌分别与氮、磷肥配合喷施对冬小麦锌吸收、转运率及锌肥利用率的影响。【方法】于2010-10-2012-06,以冬小麦小偃22为供试材料,采用2年田间定位试验,设置了3种栽培模式(常规、覆膜、补灌),3个施氮水平(0,120,240kg/hm2),4个喷肥处理(喷蒸馏水(CK)、喷Zn、喷Zn+N、喷Zn+P),分析不同栽培模式及氮肥用量下锌分别与氮、磷肥配合喷施后小偃22各器官锌含量、籽粒和秸秆锌携出量、籽粒锌转运率以及锌肥利用率的变化。【结果】与常规和覆膜栽培模式相比,补灌模式提高了籽粒和秸秆锌的携出量,覆膜可提高籽粒锌转运率。与不施氮相比,土施氮肥明显提高了小麦籽粒、茎秆和叶片锌含量及锌肥料利用率,而土施氮肥明显降低了籽粒锌转运率。与CK相比,喷锌处理(喷Zn、喷Zn+N、喷Zn+P)明显提高了小麦籽粒锌含量及锌携出量,各喷锌处理表现为喷Zn+N、喷Zn>喷Zn+P>CK,其中喷Zn+N处理小麦籽粒锌含量提高幅度平均为92%;喷锌处理也明显提高了茎秆、叶片及颖壳锌含量及秸秆锌携出量。喷锌处理锌转运率总体上均明显降低。喷Zn+P处理的锌肥利用率与喷Zn、喷Zn+N处理相比明显降低。同时,不同年份籽粒锌含量、锌转运率及锌肥利用率也存在明显差异。【结论】在补灌栽培模式下,施氮量为120kg/hm2时,单独喷施锌肥或锌与氮肥配合喷施,是潜在缺锌土壤区提高小麦籽粒锌含量和锌肥利用率的有效措施。

Nitrogen recovery and nitrate leaching of controlled release nitrogen fertilizer in irrigated paddy soil

Ordinary high nitrogen fertilizer often results in nitrate (NO3--N) leaching and low recovery. Microplot and field plot experiments were conducted to determine the effect of controlled release nitrogen fertilizer (CRNF) on reco very and nitrate leaching on paddy soils. During two early rice cropping seasons (2002 and 2003), a single basal application of CRNF at 90 kg N ha-1 increased grain yields by 7.7%to 11.6%compared with two applications of urea. Estimated by the difference method fertilizer N recovery of CRNF (mean 76.3%) was 38.9 pe rcentage point higher than that of urea (mean 37.4%); estimated by 15N isotope method (mean 49.6%) CRNF (mean 67.1%) was 35.9 percentage point higher than ur ea (mean 31.2%). NO3--N leaching losses were 9.19 and 6.70 kg ha-1 for urea and CRNF, respectively. NO3--N leaching during the early rice cropping season was 27.1 %lower from CRNF than from two applications of urea. These losses repr esent 10.2%and 7.4%of applied urea-N and CRNF-N. Results from this study ind icate that CRNF improves N recovery and reduces NO3--N leaching and increases rice yield.

Effects of Nitrogen Treatments on Organic Carbon Mineralization of Citrus Orchard Soil

[Objective] This study aimed to investigate the effect of soil organic carbon mineralization at different temperature on the amount of nitrogen application, in order to provide references for the establishment of carbon circulation model for orchard eco-system. [Method] The effects of nitrogen treatments on soil organic carbon mineralization of citrus orchard soil were investigated under 10, 20, 30 ℃ by laboratory simulated experiment. [Result] The mineralization rate decreased quickly at the be- ginning of the experiment but remained stable at the late period under three temper- ature treatments. The amounts of CO2 ranged from 1 328.25-2 219.42 mg/kg under three temperature condition, and the amount of soil organic carbon mineralization of 100 mg/kg （N4） treatment was the greatest, while that of CK was the lowest. High level nitrogen treatment （N4 and N3） were significant higher than the lower level nitro- gen treatment （N2 and N1）. The soil organic carbon mineralization rate increased with the temperature from 10 to 30℃. The dependence of soil carbon mineralization to temperature （Q10） was different under different nitrogen treatments that the Qlo value of N2 treatment was the lowest while that of the N4 treatment was the greatest. The soil organic carbon mineralization in Citrus orange orchard soil was affected significantly by high level nitrogen treatment, but with no significance under lower nitrogen treatment. [Conclusion] The dependence of soil carbon mineralization to temperature （Q10） increased with the increasing nitrogen input. The combination of nitrogen with temperature may increase the CO2 emission from Citrus orchard soil.

Moving Dynamics of Nitrate Nitrogen in Soil of Maize Field on Meadow Soil of Daling River Valley in Liaoning and Its Fertilization Controlling

The moving dynamics of nitrate nitrogen（NO3-N）in soil of maize field on meadow soil of Daling river valley in Liaoning and its rational fertilization controlling were discussed in this study by the designing of different kinds of N application methods.The results showed that the content of NO3-N in soil was increased with the amount of nitrogen fertilizer;At the same amount of nitrogen fertilizer,the content of NO3-N in soil showed a trend of chemical fertilizerstraw treatmentslow controlled release fertilizer.Based on the requirement of roots in different growth stages to nutrition,the migration directions of NO3-N could be regulated by each layer of soil.In the early growth stage,the NO3-N would move upward,while it moved downward in the late growth stage.Straw returning treatment could improve the keeping ability of soil to NO3-N and avoid the downward migration of NO3-N,as well as reduce the damage of groundwater pollution.The use of slow controlled release fertilizer had achieved the continuing releasing of nutrition.Moreover,the peak of nutrition releasing had been delayed for 30 d,which had met the requirement of nutrient supply in maturing stage.The yield of slow controlled release fertilizer treatment was the highest with the least accumulation of NO3-N and less negative influence on environment.The yield of straw returning treatment and chemical fertilizer treatment was closed to each other.

Effect of Long-Term Fertilization on Organic Carbon and Nitrogen in a Subtropical Paddy Soil

A long-term experiment beginning in 1981 in Jinxian County of Jiangxi Province, subtropical China, was conducted in a paddy field under a double rice cropping system with four different fertilization regimes, including 1) no fertilizer as control (CK), 2) balanced chemical N, P, and K fertilizers (NPK), 3) organic manure using milk vetch and pig manure in the early and late rice growing season, respectively (OM), and 4) balanced chemical fertilizers combined with organic manure (NPKM). Samples (0-17 cm) of the paddy field soil, which was derived from Quaternary red clay, were collected after the late rice harvest in November 2003 for determination of total organic carbon (TOC) and total nitrogen (TN) and fractions of organic C and N. Results showed that TOC and TN in the NPKM and OM treatments were significantly higher than those in other two treatments (CK and NPK). Application of organic manure with or without chemical fertilizers significantly increased the contents of all fractions of organic C and N, whereas chemical fertilizer application only increased the contents of occluded particulate organic C (oPOC) and amino acid N. In addition, application of organic manure significantly enhanced the proportions of free particulate organic carbon (fPOC) and oPOC in total C, and those of amino sugar N and amino acid N (P < 0.01) in total N. In contrast, chemical fertilizer application only increased the proportions of oPOC and amino acid N (P < 0.05). There were no significant differences in either contents or proportions of soil organic C and organic N fractions between the NPKM and OM treatments. These indicated that organic manure application with or without chemical fertilizers played the most significant role in enhancing soil organic C and N quantity and quality in the paddy field studied.

Nitrogen Recommendations for Summer Maize in Northern China Using the N_min Test and Rapid Plant Tests

A field experiment with a split-plot design was carried out at Dongbeiwang Farm in Beijing Municipality to establish reliable N fertilizer recommendation indices for summer maize (Zea mays L.) in northern China using the soil Nmin (mineral N) test as well as the plant nitrate and SPAD (portable chlorophyll meter readings) tests. The results showed that Nmin sollwert (NS) 60 kg N ha-1 at the third leaf stage and N rate of 40 to 120 kg N ha-1 at the tenth leaf stage could meet the N requirement of summer maiz…

Effects of Agricultural Practices on Soil Organic Nitrogen Fractions in an Inceptisol of a Cocoa Plantation

The effect of agricultural practices on soil organic nitrogen （N） fractions in a cocoa plantation has not been much revealed till now. Despite the fact that soil organic N has been long admitted for its importance to maintain soil fertility. Presented field experiment was conducted in Kaliwining Experimental Station, Indonesian Coffee and Cocoa Research Institute （ICCRI）, Jember, East Java, Indonesia, to investigate the effect of cocoa farm management, namely fertilization, weeding and soil tillage on the content of soil organic N fractions. The design of experiment was arranged in a split-split plot with two levels of weeding as main plots, two levels of soil tillage as subplot and three different fertilizer treatments as sub-sub plot. The analysis of soil N including total N and soil organic N fractions, namely, total hydrolized N, ammonium N, amino sugar N and amino acid N, were performed. The result showed that the effect of fertilization treatment was significant to the content of total N, ammonium N, amino sugar N and amino acid N. No-tillage treatment resulted in total N and amino sugar-N content increasing by 8% and 24%, respectively, over tillage treatment. Slashing treatment caused increase of the total N by 3% from herbicide treatment, whilst decrease of ammonium N and amino sugar N by 7% and 24%, respectively.

Influence of the Type of Fertilization on Nitrogen Balance of the Mountain Meadow

Among fertilizer ingredients nitrogen is the one noted for biggest losses because its susceptibility to volatilize to the atmosphere and to be leached away from the soil. These losses depend on the level and mode of fertilization. It appears that every year in Poland river waters transport to the Baltic Sea from the whole area about 180 thousand tons of the nutrient. The largest portion of this load is ascribed to agriculture. This study focused on the highland areas, which are commonly seen as a water supplying region owing to the fact that they cover about 35% of water need in the authors＇ country. Specificity of grassland fertilization in these lands is high contribution of natural fertilizers including dunging with fresh manure left by penned animals, particularly by sheep. Authors decided to assess the influence of dunging by folded sheep on meadow nitrogen balance and on its concentration in percolating water. It was demonstrated that a nitrogen balance was highly negative for each object, so the grassland plants supplied their needs in large part with nitrogen from mineralization of soil organic matter. Relatively high loads of nitrogen leached out of the folded objects indicate that nitrogen from mineral fertilizers is better utilized by grassland herbage and thus is much safer for soil and water environment.

Responses of Agronomic Benefit and Soil Quality to Better Management of Nitrogen Fertilizer Application in Greenhouse Vegetable Land

As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production. An experiment was carried out in Shouguang, Shangdong Province, China to evaluate agronomic benefit and soil quality under different N applications, including the conventional chemical N rate （1000 kg N ha^（-1） season^（-1）, N1）, 70% of N1 （N2）, 70% of N1 ＋ maize straw （N3）, 50% of N1 ＋ maize straw ＋ drip irrigation （N4）, and 0% of N1 （NO）, during two successive growing seasons of autumn-winter （AW） and winter-spring （WS）. The maximum yields for N4 were 1.1 and 1.0 times greater than those for N1 in the AW and WS seasons, respectively. N agronomic efficiency （AEN） and apparent N recovery efficiency （REN） were greatest with the N4. A significant relationship was found between soil NO3-N content and electrical conductivity （EC） （R^2 = 0.61 in the AW season and R^2= 0.29 in the WS season）. Reducing N fertilizer decreased soil NO3-N accumulation （20.9%-37.8% reduction in the AW season and 11.7%-20.1% reduction in the WS season） relative to the accumulation observed for N1 within the 0-100 cm soil layer. Soil urease and invertase activities were not significantly different among N treatments. The N4 treatment would be practical for reducing excess N input and maintaining the sustainability of greenhouse-based intensive vegetable systems in Shouguang.

Influence of Long-Term Fertilization on Selenium Accumulation in Soil and Uptake by Crops

Continuous applications of organic and inorganic fertilizers can affect soil and food quality with respect to selenium （Se） concen- trations. A long-term （over 20 years） experimental field study, started in 1989, was conducted to investigate the changes in soil Se fractions and its uptake by crops, as affected by different fertilizer practices, in the North China Plain with an annual crop rotation of winter wheat and summer maize. The long-term experiment was arranged in a complete randomized block design consisting of 4 replications with 7 fertilizer treatments： 1） organic compost （OC）, 2） half organic compost plus half N-P-K chemical fertilizers （OC ＋ NPK）, 3） N-P-K fertilizers （NPK）, 4） N-P fertilizers （NP）, 5） P-K fertilizers （PK）, 6） N-K fertilizers （NK）, and 7） an un-amended control. Soil samples from the surface （20 cm） were collected in 1989, 1994, 1999, 2004 and 2009 to characterize Se and other soil properties. In 2009, the average soil Se concentrations in the treatments （149 ± 8 beg kg-1） were higher than those in the soil samples collected in 1989 at the beginning of the experiment （112 4- 4 beg kg-1）, and decreased in the order of OC 〉 OC ＋ NPK 〉 NPK NP 〉 PK NK 〉 control. Sequential extraction showed the oxidizable fraction （50.06%± 3.94%） was the dominant form of Se in the soil, followed by the residual fraction （24.12% ± 2.89%）, exchangeable fraction （15.09% ± 4.34%） and Fe-Mn oxides fraction （10.73%±4.04%）. With an increase of soil K, the exchangeable Se concentrations in the soil increased. The Se concentrations in the soil tillage layer （0-20 cm） were mainly related to soil organic carbon （SOC）, although different contributions came from atmospheric deposition, irrigation and fertilizers. With the accumulation of SOC, the uptakes of soil Se by two crops were inhibited. For the OC and OC ＋ NPK treatments, Se concentrations in wheat grains were lower than the critical standard of Se in stable food （100 μg kg·1]. Additionallv. Se concentrations in grains were also decreased by the deficiencies of major soil nutrients, especially P.