水肥耦合对小麦/玉米带田产量及构成因素的影响

采用"3414"最优回归设计方案,于2007-2008年在甘肃省农业科学院张掖节水试验站,开展不同水肥耦合处理小麦/玉米带田产量效应研究。结果表明,不同水肥耦合模式对小麦/玉米带田产量的影响较大,其差异达极显著水平。其中,氮肥对产量的贡献最大,水分次之,磷肥最小,氮肥对带田混合产量的绝对贡献率达79.4%,而水分对带田混合产量的绝对贡献率达为52.9%;水肥耦合效应为:水氮耦合水磷耦合氮磷耦合;获得高产量12 952.5~13 880.0kg/hm2的施氮量为420~630kg/hm2、灌水量为5 550~6 750m3/hm2、施磷量为120kg/hm2。相关分析表明,施氮量和灌水量与间作玉米的穗粒数、千粒质量、穗粒质量、株高均呈极显著正相关,施氮量与间作小麦的穗粒质量、穗粒数呈极显著正相关。     

Organic input quality is more important than its quantity: C turnover coefficients in different cropping systems

Annual C input to soil is a major factor affecting soil organic carbon (SOC) dynamics. However different types of C-sources can have different behaviour, in relation to their chemical characteristics and how they interact with soil. Root-derived C, in particular, should be more efficient than other organic materials as a result of the physicochemical and biological characteristics of the surrounding environment, leading to a reduction in the C decomposition rate.To test this hypothesis, we considered a long-term experiment underway in Northern Italy since 1962, comparing permanent meadow and 6 different crop rotations over a wide range of nutrient inputs, in both organic and inorganic forms. C inputs from amendments were measured and those from crops were calculated using allometric functions and crop and residues yields. The time evolution of SOC was studied through a single-pool, first-order kinetic model, allowing the estimation of humification coefficients for residues, roots, farmyard manure and cattle slurries.The highest value of the humification coefficient was estimated for farmyard manure, which confirmed its high efficiency in stabilising SOC content. Root C presented a humification coefficient 1.9 times higher than above-ground plant materials while slurries were intermediate, with a humification coefficient roughly half that of farmyard manure and even lower that of roots.The quality of C input thus seems of fundamental importance for evaluating the sustainability of different cropping systems in terms of SOC dynamics.     

农民学分制学历教育模式研究

农业职业教育是服务"三农"的教育。针对农村剩余劳动力提出农民学分制学历教育培养模式,将课堂搬到"田间地头",最大限度地发挥农业职业学校服务于经济社会的职能,结合教育与生产实际,融合专业与产业,实现让广大农民接受教育的目标。     

硼肥用量对玉米生长发育及产量的影响

以郑单958和豫单606为试验材料,采用盆栽试验方法,探索不同硼肥用量对玉米产量及生长发育的影响。结果表明,施用适量硼肥可促进玉米生长发育,显著提高叶面积指数,使植株干物质积累量增加,同时硼肥能够促进干物质向果穗运输。施用硼肥能够促进玉米穗分化,使雌雄间隔期缩短,显著提高花丝数和花丝生长速率,进而增加穗粒数。施用硼肥显著提高玉米产量,且不同用量对其影响不同,3.33 mg/kg土壤硼肥处理的效果最为显著,郑单958和豫单606分别较不施硼肥处理增产14.3%和17.4%;施用量为13.3 mg/kg时郑单958增产3.5%;豫单606产生中毒症状,产量较对照降低4.4%。     

Variations of SOC and MBC observed in an incubated brown loam soil managed under different tillage systems for 12 years

To assess changes in organic carbon pools, an incubation experiment was conducted under different temperatures and field moisture capacity (FMC) on a brown loam soil from three tillage practices used for 12 years: no‐till (NT), subsoiling (ST) and conventional tillage (CT). Total microbial respiration was measured for incubated soil with and without the input of straw. Results indicated that soil organic carbon (SOC) and microbial biomass carbon (MBC) under ST, NT and CT was higher in soil with straw input than that without, while the microbial quotient (MQ or MBC: SOC) and metabolic quotient (qCO₂) content under CT followed the opposite trend. Lower temperature, lower moisture and with straw input contributed to the increases in SOC concentration, especially under NT and ST systems. The SOC concentrations under ST, with temperatures of 30 and 35°C after incubation at 55% FMC, were greater than those under CT by 28.4% and 30.6%, respectively. The increase in MBC was highest at 35°C for 55%, 65% and 75% FMC; in soil under ST, MBC was greater than that under CT by 199.3%, 50.7% and 23.8%, respectively. At 30°C, the lower qCO₂ was obtained in soil incubated under NT and ST. The highest MQ among three tillage practices was measured under ST at 55% FMC, NT at 65% FMC and CT at 75% FMC with straw input. These data indicate the benefits of enhancing the MQ; the low FMC was beneficial to ST treatment. Under higher temperature and drought stress conditions, the adaptive capacity of ST and NT is better than that of CT.     

便携式XRF仪现场快速测定土壤中Pb的可行性研究

便携式XRF分析仪具有轻便、快速和可测对象较多与测量元素较广等特点而广泛应用于矿石、土壤等方面快速检测,但土壤的现场快速测定结果的准确性有待进一步研究与探讨。以安宁河谷平原土壤中Pb为研究对象,通过对便携式XRF仪现场快速检测结果与实验室分析结果的对比和影响因素的分析,建立基于安宁河谷平原表层土壤快速测定结果的线性函数为y=1.170 9x-17.326 0(R~2=0.992 9,x为现场检测结果),探讨其影响因素,为该区域表层土壤中Pb快速检测结果提供依据。     

土壤温度对作物根区环境及玉米根冠生长的调控研究进展

土壤温度对作物的生长发育具有很强的调控作用。在全球气候变化背景下,根区土壤温度对玉米生长的影响及其调控机制已成为当前研究的一个热点。结合目前农业生产中土壤低温和高温对玉米造成危害的现状,从土壤温度对作物根区土壤环境以及玉米根系生长、冠层发育与产量形成的影响方面,综述土壤温度对玉米生长发育调控作用的研究进展,介绍改变土壤温度的措施以及对玉米土壤温度研究的发展方向进行展望,为今后的研究提供参考。     

Dynamic change of mineral nutrient content in different plant organs during the grain filling stage in maize grown under contrasting nitrogen supply

The introduction of new hybrids and integrated crop-soil management has been causing maize grain yield to increase. However, less attention has been paid on the nutrient concentration of the grain; this aspect is of great importance to supplying calories and nutrients in the diets of both humans and animals worldwide. Increasing the retranslocation of nutrients from vegetative organs to grain can effectively increase the nutrient concentration of grain and general nutrient use efficiency. The present study involved monitoring the dynamic change of macro- and micronutrients in different organs of maize during the grain filling stage. In addition, the mobility of different elements and their contribution to grain nutrient content were evaluated in a 2-year experiment under low (LN, no N supplied) and high N (HN, 180 kg N ha⁻¹) supply. Under HN supply, the net remobilization efficiency (RE) of the vegetative organs as a whole (calculated as nutrient remobilization amount divided by nutrient content at silking) of N, P, K, Mn, and Zn were 44%, 60%, 13%, 15%, and 25%, respectively. The other nutrients (Mg, Ca, Fe, Cu, and B) showed a net accumulation in the vegetative organs as a whole during the grain filling stage. Among the different organs, N, P, and Zn were remobilized more from the leaves (RE of 44%, 51% and 43%, respectively) and the stalks (including leaf sheaths and tassels) (RE of 48%, 71% and 43%, respectively). K was mainly remobilized from the leaves with RE of 51%. Mg, Ca, Fe, Mn, and Cu were mostly remobilized from the stalks with the RE of 23%, 9%, 10%, 42%, and 28%, respectively. However, most of the remobilized Mg, Ca, Fe, Mn, Cu, and Zn were translocated to the husk and cob, which seemingly served as the buffer sink for these nutrients. The REs of all the nutrients except for P, K, and Zn were vulnerable to variations in conditions annually and were reduced when the grain yield and harvest index were lower in 2014 compared with 2013. Under LN stress, the RE was reduced in P and Zn in 2013, increased in Cu and unchanged in other nutrients. The concentration of these nutrients in the grain was either unchanged (P, K, Ca, Zn, and B) or decreased (N, Mg, Fe, Mn, and Cu). It is concluded that grain N, P, K, Mn, and Zn, but not Mg, Ca, Fe, Cu, and B concentration, can be improved by increasing their remobilization from vegetative organs. However, enhancing the senescence of maize plant via LN stress seems unable to increase grain mineral nutrient concentration. Genetic improvement aiming to increase nutrient remobilization should take into account the organ-specific remobilization pattern of the target nutrient.     

不同肥力水平下种植密度对浚单29产量性状及产量的影响

[目的]探寻浚单29不同肥力水平地区的适宜种植密度。[方法]研究在高产田与一般田2种肥力水平下浚单29种植密度与产量及其相关产量性状的关系。[结果]2种肥力水平下通过种植密度变化影响穗部性状来影响产量,相同密度,一般田肥力水平下,密度对穗部性状影响大于高产田对穗部性状影响。[结论]在一般田肥力水平下,浚单29最适宜密度为6.75万株/hm2,高产田肥力水平下,浚单29最适宜密度为7.50万株/hm2。     

不同施肥方式对红壤蔬菜田氨氧化细菌和氨氧化古菌群落的影响

通过构建氨单加氧酶基因(amoA)克隆文库,研究在红壤蔬菜田上只施用磷钾化肥(PK)、只施氮磷钾化肥(NPK)、施用腐熟有机肥(DNPK)和施用新鲜有机肥(FNPK)等4种不同施肥处理的土壤氨氧化细菌(AOB)和氨氧化古菌(AOA)群落多样性及与土壤脲酶活性的相关性。结果表明:施加有机肥处理(DNPK和FNPK)的蔬菜田土壤的AOB文库和AOA文库OTU数量和Shannon指数高于只施用无机肥(NPK和PK)处理的蔬菜田土壤;DNPK和FNPK处理的土壤优势AOB菌群为多形亚硝化叶菌(Nitrosolobus multiformis),比例分别为88.5%和68.5%,NPK和PK处理的土壤优势AOB菌群为亚硝化单胞菌属(Nitrosospirasp.),比例分别为54.8%和65.5%;DNPK、FNPK、NPK和PK处理土壤优势AOA菌群均为阿伯丁土壤亚硝化细杆菌侯选种(CandidatusNitrosotalea devanaterra),比例分别为90.9%、84.4%、77.8%和45.2%;施加有机肥处理(DNPK和FNPK)的土壤脲酶活性和氨氧化微生物的多样性指数都高于只施用无机肥处理(NPK和PK);AOA群落多样性指数与土壤脲酶活性呈显著正相关,而AOB群落多样性与土壤脲酶活性相关性不显著。总体来看,有机肥比无机肥处理提高了AOA和AOB群落多样性,且AOA在红壤蔬菜田土壤氨氧化过程中起着更为重要的作用。