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( 2) 根據(jù)作物營養(yǎng)特性 ?葉菜類、茶、水稻、小麥、玉米等作物需氮較多 ?大豆、花生等 豆科作物可利用根瘤進(jìn)行共生固氮,只需在生長初期施用少量氮肥 . ?甘薯、馬鈴薯、甜菜、甘蔗等淀粉和糖類作物只在生長初期需要充足的氮素 耐肥品種產(chǎn)量較高,需氮量大;而耐瘠品種,需氮量較小,產(chǎn)量也較低 ( 3) 根據(jù)氮肥特性 ?硝化抑制劑 ?深施覆土或氮肥顆粒化 ( 4) 元素間平衡 其他必須養(yǎng)分的有效性 ( 5) Soil conditions The amount of available N in soil ( 6) Crops species Leaf vegetables, tea, rice and corn need more N Legume can fix the atmospheric N2, so the N fertilizer is needed only at the early growing stage Potato, sugarcane and beet need adequate N at early growing stage. The more yield, the more N needed. ( 7) Characteristic of fertilizer Nitrification inhibitors Improve N application methods, such as deep incorporation of NH4+ and urea or granular ( 8) Balance of the nutrients Other plant nutrients availability 。 B、 Ca, reuse is very low, nutrient deficiency occurs first in the growing point.. ? 答:鐵是鐵氧還原蛋白的重要組成成分,鐵氧還原蛋白在植物體內(nèi)硝酸還原中傳遞電子,缺鐵時,硝酸還原受到抑制,所以體內(nèi)硝酸鹽含量增加。 N、 P、 K、 Mg, reuse ability, nutrient deficiency occurs first in old leaves。 Root secretion of anic acids and other substances can increase the solubility of insoluble material. Rhizosphere have more energy materials, microbial activity was higher in the rhizosphere is conducive to the release of insoluble nutrients. 。 Nitrogenfixing legume nodules obtained from the host plant carbohydrates as an energy source, an adequate supply of host carbohydrates, nodule nitrogen fixation ability, potassium can increase the legume crop photosynthesis, increasing body carbohydrate content, and can promote the transport of carbohydrates, Therefore, an adequate supply of potash can increase the amount of nitrogenfixing root nodules. ? 答: 根系分泌的有機(jī)酸等物質(zhì)可增加難溶性物質(zhì)的溶解度。 而氯離子和鈣離子結(jié)合形成氯化鈣,易發(fā)生淋失,使土壤孔隙減少,同時土壤團(tuán)粒結(jié)構(gòu)也發(fā)生改變,造成板結(jié)。 Cropping system dry lightheavy water principle. Because in the cropping system, soil experiencing from the wet and dry from the wet to dry process, dry paddy soil by the wet process, waterlogging conditions, changes in pH, moisture content increases, etc., can make available phosphorus content increased, while in the dry and wet soil from the low winter temperatures often reduce their phosphorus content, which makes the fertilizer applied in the dry, the rice was made after a larger aftereffect, and applied in rice phosphate on the contribution of dry stubble after smaller. ,是否會造成土壤板結(jié)? 答: 會, 向土壤中過量施入鉀肥時,鉀肥中的鉀離子置換性特別強(qiáng),能將形成土壤團(tuán)粒結(jié)構(gòu)的多價陽離子置換出來,而一價的鉀離子不具有鍵橋作用,土壤團(tuán)粒結(jié)構(gòu)的鍵橋被破壞了,也就破壞了團(tuán)粒結(jié)構(gòu),致使土壤板結(jié)。 Reactions of dissoluble P in the soil: When the dissoluble P was applied to the soil, the fertilizer dissolves and releases soluble P into the soil solution and increases H+ concentration nearby ,which will increase the solubility of Ca ,Fe and phosphates react quickly with the cations in the solution to form insoluble of the phosphorus may be adsorbed onto the oxide a few days most of the soluble P is converted into insoluble pounds into the soil .With time these may be converted into forms that are even more insoluble, The process is called the abnormal solubility of superphosphate or phosphate degradation ,如何合理使用磷肥?為什么? 答: 水旱輪作制 “ 旱重水輕 ”的原則。一部分磷則吸附在土壤中的氧化物表面 , 幾天后,絕大多數(shù)的可溶性磷轉(zhuǎn)化為難溶的磷化合物。施入土壤后,肥料溶解,向土壤溶液中釋放出磷酸根,增加施肥點附近的 H+濃度,增加土壤中鈣,鐵和鋁的溶解度。 With the help of microbe, rough anic materials were transformed to quality fertilizer after mineralization and humification. The first stage dominated by mineralization and the second dominated by humification. 13.為什么葉菜比果菜含鈣量高? 答:鈣在植物體內(nèi)是不可轉(zhuǎn)移元素,當(dāng)植株進(jìn)入生殖生長期,鈣不能轉(zhuǎn)移到果實中,繼續(xù)存在于莖葉中,因此葉菜比果菜含鈣量高。 答: 使粗有機(jī)物質(zhì)在微生物的作用下經(jīng)過礦化和腐殖化過程而成為優(yōu)質(zhì)肥料。 If the post pile was dry state, that too little water, holes in the top of the heap with water。 The same points are yellow leaves。 答: 相同 點都是 葉片發(fā)黃 ; 不同 點是 缺硫上部新葉發(fā)黃,缺氮老葉發(fā)黃 。 答:有機(jī)肥料 大都不能直接被作物吸收利用,通過腐熟過程,使有機(jī)物料盡快釋放養(yǎng)分,還可經(jīng)過發(fā)酵過程產(chǎn)生的高溫殺滅寄生蟲卵和各種病原菌,殺死各種危害作物的病蟲害及雜草種子,實現(xiàn)無害化的目的,同時還縮小了有機(jī)物料龐大的體積,節(jié)約運(yùn)輸成本,施用后便于耕作,提高了耕作質(zhì)量。 Soil adsorption of ammonium to reduce ammonia volatilization and nitrification, to prevent nitrate leaching and denitrification of deep Shiyou Li in the roots under the bar, expand the root of the nutrition area, deep Shiyou Li on increasing the ammonium in the soil diffusion area and increased opportunities for root absorption, thereby increasing the utilization of nitrogen.. 。 Urea applied to soil after a small portion of the molecule dissolved in soil solution in the state, the role of soil adsorption through hydrogen bonds, most of the other under the action of the enzyme in the hydrolysis of urea into ammonium carbonate, ammonium hydrogen and then generate the carbon acid and ammonium hydroxide. And NH4 + can be absorbed by plants and soil colloid adsorption, HCO3can also be absorbed by plants. ?其在農(nóng)業(yè)生產(chǎn)中的意義? 答: 土壤供氮能力指