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对磷钾肥利用率和需用量计算探讨 总被引:7,自引:0,他引:7
P、K肥当季习惯利用率不考虑肥料与土壤养分的交换利用量,以无肥对照为基数,把利用率估算过低。原需肥量计算公式纯粹是利用率不妥计算的逆运算。应该从长期施肥效应考虑,残留P、K量也可交换利用及再利用。因此速效磷P、K肥平衡最佳需要量等于带出量除以总回收率。引用资料初步验证表明新算法成立,且很合理适用。 相似文献
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This study was conducted to examine whether the applications of N-inputs (compost and fertilizer) having different N isotopic compositions (δ15N) produce isotopically different inorganic-N and to investigate the effect of soil moisture regimes on the temporal variations in the δ15N of inorganic-N in soils. To do so, the temporal variations in the concentrations and the δ15N of NH4+ and NO3− in soils treated with two levels (0 and 150 mg N kg−1) of ammonium sulfate (δ15N=−2.3‰) and compost (+13.9‰) during a 10-week incubation were compared by changing soil moisture regime after 6 weeks either from saturated to unsaturated conditions or vice versa. Another incubation study using 15N-labeled ammonium sulfate (3.05 15N atom%) was conducted to estimate the rates of nitrification and denitrification with a numerical model FLUAZ. The δ15N values of NH4+ and NO3− were greatly affected by the availability of substrate for each of the nitrification and denitrification processes and the soil moisture status that affects the relative predominance between the two processes. Under saturated conditions for 6 weeks, the δ15N of NH4+ in soils treated with fertilizer progressively increased from +2.9‰ at 0.5 week to +18.9‰ at 6 weeks due to nitrification. During the same period, NO3− concentrations were consistently low and the corresponding δ15N increased from +16.3 to +39.2‰ through denitrification. Under subsequent water-unsaturated conditions, the NO3− concentrations increased through nitrification, which resulted in the decrease in the δ15N of NO3−. In soils, which were unsaturated for the first 6-weeks incubation, the δ15N of NH4+ increased sharply at 0.5 week due to fast nitrification. On the other hand, the δ15N of NO3− showed the lowest value at 0.5 week due to incomplete nitrification, but after a subsequence increase, they remained stable while nitrification and denitrification were negligible between 1 and 6 weeks. Changing to saturated conditions after the initial 6-weeks incubation, however, increased the δ15N of NO3− progressively with a concurrent decrease in NO3− concentration through denitrification. The differences in δ15N of NO−3 between compost and fertilizer treatments were consistent throughout the incubation period. The δ15N of NO3− increased with the addition of compost (range: +13.0 to +35.4‰), but decreased with the addition of fertilizer (−10.8 to +11.4‰), thus resulting in intermediate values in soils receiving both fertilizer and compost (−3.5 to +20.3‰). Therefore, such differences in δ15N of NO3− observed in this study suggest a possibility that the δ15N of upland-grown plants receiving compost would be higher than those treated with fertilizer because NO3− is the most abundant N for plant uptake in upland soils. 相似文献
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水稻产量对长期不同施肥和环境的响应 总被引:1,自引:1,他引:1
以开始于1982年的不同施肥长期定位试验为平台,选择氮磷钾肥(NPK)、有机肥(牛粪,M)、氮磷钾肥+有机肥(NPKM)、氮磷肥+有机肥(NPM)、氮钾肥+有机肥(NKM)和磷钾肥+有机肥(PKM)共6个处理,采用产量年际变化、变异系数(CV)、产量可持续指数(SYI)、肥料增产贡献率及AMMI模型对影响双季稻稻谷总产量稳定性的施肥处理、环境和二者互作进行综合分析,研究历年稻谷产量(1982—2012年)对长期不同施肥和环境的响应特征。结果表明:NPKM处理稻谷产量最高;在养分投入量相同的情况下,单施有机肥和单施化肥对于早稻产量的影响效果一致,但单施有机肥较单施化肥有利于提高晚稻稻谷产量。不同施肥处理稻谷产量CV随试验时间延长逐渐降低,有机无机配施相比较单施化肥能够减小产量CV,各处理晚稻产量的CV大于早稻,但其SYI值小于早稻。NPKM处理的SYI值最高,为0.51;M和NPK处理的SYI值分别为0.44和0.42。肥料对于产量的贡献率表现为:有机肥化肥氮化肥磷化肥钾。AMMI模型交互效应主成分(IPCA)表明,不同施肥处理在不同试验年份对环境的响应不一样。综合以上分析结果,氮磷钾完全肥基础上配施有机肥(NPKM)是该区域双季稻高产和稳产的最佳施肥措施。 相似文献
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Effective nitrification inhibitors may improve fertilizer recovery in irrigated cotton 总被引:6,自引:0,他引:6
N fertilizer is often poorly recovered in irrigated cotton production, due to N loss through denitrification. We researched the ability of inhibitors to delay nitrition and reduce the availability of NO3
- to denitrifying microorganisms and thus improve N fertilizer recovery, 2-Ethynylpyridine, etridiazole, and nitrapyrin proved highly effective nitrification inhibitors, although nitrification was evident several weeks after their application. CaC2 was relatively ineffective, even when wax-coated to prolong the evolution of C2H2. Phenylacetylene and ethynylcyclohexanol were also ineffective, despite having a chemical structure similar to 2-ethynylpyridine. A strong association was identified between each compound's ability to inhibit nitrification and its capacity to improve N fertilizer recovery. In one experiment, N fertilizer recovery was increased by 50% with 2-ethynylpyridine, etridiazole, or nitrapyrin application, from 33% without inhibitors. The inhibitors had little effect on fertilizer recovery where N losses were relatively small. 3-Methyl pyrazole significantly increased N uptake and lint yield, but the nitrification inhibitors had no significant effect on N uptake or on yield in two of the three of the cotton crops. A laboratory study confirmed that nitrification inhibitor effectiveness declined in the order 2-ethynylpyridine>etridiazole>nitrapyrin>3-methyl pyrazole>phenylacetylene>CaC2>ethynylcyclohexanolThis research was conducted at Australian Cotton Research Institute, CSIRO Division of Plant Industry, Locked Bag 59, Narrabri, NSW 2390, Australia 相似文献
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化肥氮磷优化减施对水稻产量和田面水氮磷流失的影响 总被引:9,自引:0,他引:9
为探讨氮(N)、磷(P)减量对降低稻田养分地表径流损失风险的影响,以毛里湖稻区为研究对象,连续两年(2016—2017年)进行田间小区试验,研究化肥氮磷优化减施对水稻产量和生长期内田面水N、P动态变化特征及径流流失的影响。结果表明:常规施肥处理(CF)和有机替代20%化肥N处理(0.8FN+0.2ON)稻田田面水总氮(TN)、NH_4~+-N和总磷(TP)浓度在施肥后迅速达到峰值,之后逐渐下降。而控释氮肥减N处理能有效减缓N素释放速度,田面水N素流失量远低于CF处理,且磷肥减量处理TP流失量低于CF处理。与CF处理相比,控释氮肥减N 20%(0.8N)和控释氮肥+过磷酸钙减量20%(0.8NP)处理水稻两年平均分别增产5.55%、3.22%,N素累积量分别提高19.01%、13.66%,氮肥偏生产力分别显著提高31.94%、28.83%,氮肥农学利用率分别提高47.52%、33.75%,氮肥吸收利用率分别提高95.30%、73.31%。0.8NP处理较0.8N处理水稻磷肥偏生产力两年平均显著提高22.08%,而0.8FN+0.2ON处理较CF处理P素累积量和磷肥吸收利用率分别降低11.14%、36.04%。总体而言,控释氮肥与磷肥减量既保证高产稳产,又有效降低稻田施肥初期N、P径流损失风险。在综合考虑农业生产节本增效和控制农田面源污染的前提下,可采用控释氮肥减量的施肥模式。 相似文献
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