有机和无机烟草专用肥配合施用对烟草生产效益和肥料氮素利用率的影响

通过盆栽和田间试验方法,研究了烟草无机专用肥与烟草生物有机专用肥配合施用对烟草整个生育期土壤氮素水平、烟草地上部干物质累积量、产量及其氮素利用率的影响。研究结果表明,与单施烟草无机专用、烟草生物有机专用肥相比,70%无机专用肥氮+30%生物有机专用肥氮,总施氮量为60 kg/hm2时,烟草整个生育期土壤硝态氮和铵态氮含量分别显著提高了3.75%118.14%、0 16.35%、全氮含量提高了0.77%10.42%,烟草地上部分干物质累积量增加了0.76%51.88%,增产8.63%15.28%,土壤偏生产力提高了5.39%27.24%,烟草氮素利用率提高了3.21%208.38%,烟草的生产效益和氮素利用率均达到了最佳,而生物有机专用肥氮在总氮量中所占比例为5%时,对烟草整个生育期土壤有效氮含量、烟草产量和氮素利用率作用不明显。因此,70%无机专用肥氮与30%生物有机专用肥氮配施、总氮量为60 kg/hm2是值得推荐的配施比例和用量。

施用微生物有机肥对连作条件下西瓜的生物效应及土壤生物性状的影响

为探讨施用微生物有机肥对连作条件下西瓜生长、土壤微生物的影响,在西瓜连作3年的土壤上采用小区试验方法分析施用微生物有机肥对西瓜的生物学效应及对土壤微生物群落结构的影响。试验设置4个处理,依次为健康菜园土育苗（CK）、健康菜园土育苗＋定植期增施微生物有机肥（施肥量为每株25 g）、健康菜园土＋微生物有机肥育苗（微生物有机肥︰健康菜园土=1︰49）、健康菜园土＋微生物有机肥育苗＋定植期增施微生物有机肥（施肥量为每株25 g）。结果显示：在育苗及定植期均施用微生物有机肥使西瓜的生物学性状得到显著改善。与对照相比,施用微生物有机肥使西瓜株高、叶片数、叶绿素含量、植株氮、磷、钾吸收总量以及西瓜品质、产量显著增加（P〈0.05）;同时,微生物有机肥富含优质碳源和微生物,健康菜园土育苗＋定植时增施微生物有机肥和健康菜园土＋微生物有机肥育苗＋定植期增施微生物有机肥处理土壤中细菌总量与对照相比分别增加24.9%~51.0%和35.7%~55.8%,放线菌数量分别增加18%~41%和15%~35%,真菌数量分别增加7.4%~21.9%和4.9%~31.9%;土壤中有益菌数量和放线菌与真菌的比例增加可有效抑制尖孢镰刀菌活性,对枯萎病的防治率高达83%以上。微生物有机肥能激发连作土壤有益微生物活性,显著改善和调节连作西瓜生长,对西瓜的连作障碍有明显缓解作用。

Biochar for Soil Management： Effect on Soil Available N and Soil Water Storage

Soil management technologies for climate change adaptation and mitigation are needed to increase and sustain food production in smallholder agriculture while sequestering inert carbon in the soil. In a field studies at Crops Research Institute, Kwadaso-Kumasi Ghana, a control treatment, five inorganic fertilizer combinations （P30K60, N60P30K60, N120P30K60, NlsoP30K60 and N24oP3oK6o） and four biochar rates ＋ inorganic fertilizer （2 t/ha Biochar ＋ N60P30K60, 4 t/ha Biochar ＋ N60P30K60, 6 t/ha Biochar ＋ N6oP3oK6o and 8 t/ha Biochar ＋N6oP3oK6o） were assessed for their effect on soil moisture storage, soil available nitrogen and crop yield. The test crop was okra. Biochar amendments increased soil moisture storage by 14% relative to sole inorganic fertilizer applications. Biochar ＋ inorganic fertilizer relative to sole inorganic fertilizer increased soil available nitrate concentration by 85% at 0-15 cm soil depth but decreased soil ammonium-N by 71%. Compared to control, inorganic fertilizer （P3oK6o） resulted in more than 100% increase in okra fresh fruit yield. Addition of 60 kg N/ha to P3oK6o caused 23% decline in okra fresh fruit yield but showed 60% more okra fresh fruit yield than the control. Inorganic N rates of 120,180 kg N/ha and 240 kg N/ha combined with P3oK6o however caused a decline of 74% in okra fresh fruit yield. Biochar ＋ inorganic fertilizer increased okra fresh fruit yield by 100% compared to sole inorganic fertilizer. Biochar, an inert carbon, combined with inorganic fertilizer has tremendous potential to address food insecurity through soil moisture storage and soil N availability.