Mehdi S M, Sarfraz M, Shabbir G, Abbas G
Soil Salinity Research Institute, Pindi Bhattian, Pakistan.
Pak J Biol Sci. 2007 Jul 15;10(14):2396-401. doi: 10.3923/pjbs.2007.2396.2401.
Saline sodic soils after reclamation become infertile due to leaching of most of the nutrients along with salts from the rooting medium. Microbes can play a vital role in the productivity improvement of such soils. In this study a saline sodic field having EC, 6.5 dS m(-1), pH, 9.1 and gypsum requirement (GR) 3.5 tons acre(-1) was reclaimed by applying gypsum at the rate of 100% GR. Rice and wheat crops were transplanted/sown for three consecutive years. Inorganic nitrogenous fertilizer was used with and without biofertilizers i.e., Biopower (Azospirillum) for rice and diazotroph inoculums for wheat. Nitrogen was applied at the rate of 0, 75% of recommended dose (RD), RD, 125% of RD and 150% of RD. Recommended dose of P without K was applied to all the plots. Biopower significantly improved Paddy and straw yield of rice over inorganic nitrogenous fertilizer. In case of wheat diazotroph inoculum improved grain and straw yield significantly over inorganic nitrogenous fertilizer. Among N fertilizer rates, RD + 25% additional N fertilizer was found to be the best dose for rice and wheat production in recently reclaimed soils. Nitrogen concentration and its uptake by paddy, grain and straw were also increased by biopower and diazotroph inoculum over inorganic nitrogenous fertilizer. Among N fertilizer rates, RD + 25% additional N fertilizer was found to be the best dose for nitrogen concentration and its uptake by paddy, grain and straw. Total soil N, available P and extractable K were increased while salinity/sodicity parameters were decreased with the passage of time. The productivity of the soil was improved more by biofertilizers over inorganic N fertilizers.
开垦后的盐碱土由于大部分养分与盐分一起从生根介质中淋失而变得贫瘠。微生物在提高这类土壤的生产力方面可以发挥至关重要的作用。在本研究中，通过以100%石膏需求量（GR）的速率施用石膏，对电导率为6.5 dS m(-1)、pH值为9.1且石膏需求量为3.5吨/英亩的盐碱地进行了改良。连续三年种植水稻和小麦作物。使用了无机氮肥，同时搭配和不搭配生物肥料，即用于水稻的生物动力肥（固氮螺菌）和用于小麦的固氮菌接种剂。氮肥施用量分别为推荐剂量（RD）的0%、75%、100%、125%和150%。所有地块均施用了推荐剂量的磷肥且不施钾肥。与无机氮肥相比，生物动力肥显著提高了水稻的稻谷产量和秸秆产量。就小麦而言，固氮菌接种剂比无机氮肥显著提高了籽粒产量和秸秆产量。在氮肥施用量中，发现RD + 25%额外氮肥是近期开垦土壤中水稻和小麦生产的最佳剂量。与无机氮肥相比，生物动力肥和固氮菌接种剂还提高了水稻、籽粒和秸秆中的氮浓度及其吸收量。在氮肥施用量中，发现RD + 25%额外氮肥是水稻、籽粒和秸秆中氮浓度及其吸收量的最佳剂量。随着时间的推移，土壤总氮、有效磷和速效钾增加，而盐碱化参数降低。与无机氮肥相比，生物肥料对土壤生产力的提高更为显著。
