氮、磷、钾施肥配比对桂闽引象草产量和品质的影响

以桂闽引象草为材料,采用三因素三水平正交优化设计试验,研究不同施肥水平下桂闽引象草农艺性状、产量及营养品质的变化,以探讨施肥对桂闽引象草的影响。结果表明,桂闽引象草通过合理的氮、磷、钾施肥配比,能够达到较好的生产效果,综合分析,组合N20P10K20的施肥效果最佳,即在N 20 kg/667 m^2、P 10 kg/667 m^2、K 20 kg/667 m^2的施肥配比下,桂闽引象草年鲜草产量达11 267.5 kg/667 m^2,折合干草产量为2 520.7 kg/667 m^2,比对照(无肥处理)分别增产39.74%和46.30%,粗蛋白含量12.68%,比对照增加25.60%。

氮磷钾对桔梗生长及次生代谢产物的影响

通过田间试验,采用氮、磷、钾三因素二次D-饱和最优设计研究了氮、磷、钾肥及其配比施肥对桔梗(Platyc-odon grandiflorum)生长及次生代谢产物的影响。试验结果表明,施肥能显著提高桔梗药材产量,氮、磷、钾元素对桔梗药材产量影响依次为氮>钾>磷。氮、磷、钾元素对桔梗总皂苷含量影响依次为氮>钾>磷,对桔梗植株多糖含量影响依次为磷>氮>钾;氮、磷对黄酮积累表现出一定负效应。依据桔梗药材产量及总皂苷含量提出桔梗合理施肥方案为N 150kg.hm-2、P2O579.41kg.hm-2、K2O 225kg.hm-2。

不同坡位和施肥对思茅松幼林生长的影响

在云南省景谷县内,采用氮肥、磷肥、钾肥3种肥料对不同坡位的思茅松幼林开展配方施肥试验,结果表明：坡位影响思茅松幼林的生长,山中、山下的幼林比山顶的幼林生长量高,树高、胸径分别比山顶增加了21.5%~30.3%、30.5%~38.0%,均差异显著;较适宜的施肥方案为尿素250 g＋钙镁磷400 g＋硫酸钾100 g,施肥后思茅松幼林平均树高提高17%（约40 cm）,平均胸径提高30%（约1 cm）,差异均达显著水平,同时也提高了林地土壤速效磷107.6%、全磷57.9%和全钾6.8%,并有效减缓林地有机质、速效氮、全氮、速效钾等土壤养分的流失。仅采用氮、钾配比施肥或磷、钾配比施肥,树高和胸径提高较小。3种肥料中氮肥和磷肥对思茅松树高和胸径生长影响显著,钾肥影响较小。在培育思茅松人工幼林时,采用氮、磷配比施肥对其树高和胸径生长具有促进作用。

Effects of Nitrogen,Phosphorus and Potassium Application on Growth and Dry Matter Accumulation in Mulberry

In this paper, the effect of different fertilizer treatments on the main indexes of growth and development and dry matter accumulation of perennial mulberry, which is cut and pruned in summer, were studied with ‘3414’ field experiment design. The results showed that N, P, and K at proper amounts could promote mulberry growth and development, improve its dry matter content, increase its dry matter accumulation. The effects of N, P, K on leaf yield per plant were respectively expressed as follows： N2 N3 N1 N0 , P2 P1 P3 P0 , K2 K1 K3 K0 . It can be concluded that the recommended fertilizer amounts of dry matter accumulations in mulberry leaf were 694.36 kg/hm2 of N, 198.15 kg/hm2 of P, and 274.26 kg/hm2 of K and the dry matter achieved the maximum at 8 045.04 kg/hm2 . The recommended fertilizer amounts of accumulated dry matter in branch were 1 000.05 kg/hm2 of N, 242.04 kg/hm2 of P, and 218.01 kg/hm 2 of K, and the dry matter achieved the maximum at 5 969.05 kg/hm2 . The recommended fertilizer amount in young shoots were 883.76 kg/hm2 of N, 204.48 kg/hm2 of P and 426.59 kg/hm2 of K and dry matter achieved the maximum at 1 410.24 kg/hm2 . This paper could provide reference for the construction of highly-qualified mulberry field in Sichuan hilly area.

Effects of Slow-release Fertilizer and Balanced Fertilization on Nitrogen, Phosphorus and Potassium Uptake in Peppers

Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium uptake of peppers at Jiangna Town, Yanshan County, Yunnan Province in 2011. The results showed that the dry matter accumulation in dried pepper plant, pepper yield, nitrogen, phosphorus, potassium uptake in peppers were significantly increased in all the fertilizer treat- ments, compared with those in control （no fertilizer）. Compared with conventional fertilization, balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer significantly increased dried pepper economic output by 20.94%, 17.5% and 14.54%, nitrogen uptake in dried peppers by 21.53%,18.46% and 13.19%, phosphorus uptake in dried peppers by 14.08%, 15.76% and 10.44%, potassium uptake in dried peppers by 22.66%, 15.73% and 16.28%; they also in- creased nitrogen and potassium use efficiency, but reduced potassium use efficiency due to the increased potassium addition. In treatments with balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer, the nitrogen utiliza- tion was 5.84%, 7.14% and 8.33% higher and the phosphorus utilization was 3.32%, 3.27% and 2.47% higher than those in treatment with conventional fertiliza- tion. In addition, the nitrogen application could be reduced by 20%-50% by bal- anced fertilization and the two slow-release fertilizers, thereby reducing environmen- tal pollution. Slow-release fertilizers could also reduce the frequency of fertilization and labor costs.

Study on Absorption Law of Nitrogen,Phosphorus and Potassium and Proper Nitrogen Application in Chuanxiangyou 9838 under No-tillage Cultivation

The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatments were designed to analyze the absorption laws of N, P and K, and to discuss the effects of different N fertilizer application amounts on yield and yield composition factors of Chuanxiangyou 9838. The results showed that gross nutrient absorption in Chuanxiangyou 9838 was greatly varied at different developmental stages under rice-rape rotation with no-tillage. The maximum N absorption in Chuanxiangyou 9838 appeared at jointing stage followed by heading stage, thirdly the tillefing stage ; the P absorption in Chuanxiangyou 9838 presented the consecutively slight increase during seedling stage and mature stage ; the K absorption in Chuanxiangyou 9838 was mainly conducted from jointing stage to heading stage, during which K absorption accounts for 73.4% of the total absorption in whole developmental stage. Consequently, N fertilizer should be applied earlier （ before jointing stage）, P fertilizer is suitable as base fertilizer and application of K fertilizer should be preferably conducted at early-middle period. When the yield reached 11 t/hm^2, the optimal N application amount in Chuanxiangyou 9838 was about 165 kg/hm^2.

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.

Effect of Long-Term Fertilization on Soil Productivity on the North China Plain

Soil productivity is the ability of a soil, in its normal environment, to support plant growth and can be evaluated with respect to crop production in unfertilized soil within the agricultural ecosystem. Both soil productivity and fertilizer applications affect crop yields. A long-term experiment with a winter wheat-summer maize rotation was established in 1989 in a field of the Fengqiu State Key Agro-Ecological Experimental Station, a region typical of the North China Plain, including seven treatments： 1） a balanced application of NPK chemical fertilizers （NPK）; 2） application of organic fertilizer （OM）; 3） application of 50% organic fertilizer and 50% NPK chemical fertilizers （1/2OMN）; 4） application of NP chemical fertilizers （NP）; 5） application of PK chemical fertilizer （PK）; 6） application of NK chemical fertilizers （NK）; and 7） unfertilized control （CK）. To investigate the effects of fertilization practices on soil productivity, further pot tests were conducted in 2007-2008 using soil samples from the different fertilization treatments of the long-term field experiment. The soil sample of each treatment of the long-term experiment was divided into three pots to grow wheat： with no fertilization （Potunf）, with balanced NPK fertilization （POtNPK）, and with the same fertilizer（s） of the long-term field experiment （Potori）. The fertilized soils of the field experiment used in all the pot tests showed a higher wheat grain yield and higher nutrient uptake levels than the unfertilized soil. Soil productivity of the treatments of the field experiment after 18 years of continuous fertilizer applications were ranked in the order of OM 〉 1/2OMN 〉 NPK 〉 NP 〉 PK 〉 NK 〉 CK. The contribution of soil productivity of the different treatments of the field experiment to the wheat grain yield of Potori was 36.0%-76.7%, with the PK and NK treatments being higher than the OM, 1/2OMN, NPK, and NP treatments since the soil in this area was deficient in N and P and rich in K. Wheat grain yields of PotNPK were higher than those of Potori and Potunf. The N, P, and K use efficiencies were higher in POtNPK than Potori and significantly positively correlated with wheat grain yield. Soil organic matter could be a better predictor of soil productivity because it correlated more strongly than other nutrients with the wheat grain yield of Potuf. Wheat yields of POtNPK showed a similar trend to those of Potunf, indicating that soil productivity improvement was essential for a further increase in crop yield. The long-term applications of both organic and chemical fertilizers were capable of increasing soil productivity on the North China Plain, but the former was more effective than the latter. The balanced application of NPK chemical fertilizers not only increased soil productivity, but also largely increased crop yields, especially in soils with lower productivity. Thus, such an approach should be a feasible practice for the sustainable use of agricultural soils on the North China Plain, particularly when taking into account crop yields, labor costs, and the limited availability of organic fertilizers.