Effect of Potassium and Moisture on Rape Growth and Its Nutrient Uptake

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Nutrient Uptake and Use Efficiency of Irrigated Rice in Response to Potassium Application

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.

硝酸钾配施有机肥对早熟禾生长及养分吸收的影响

早熟禾草坪在盐碱土壤上建植3~4年后会发生明显的退化,研究园林养护中采用硝酸钾配施有机肥的方式为其提供营养,对促进植株生长和提高坪用质量具有重要意义。试验设置在城市绿化带中,设置空白对照(K1)、硝酸钾化肥对照(K2)、化肥+发酵饼肥(K3)、化肥+腐殖酸复混肥(K4)4个处理,每个处理3次重复,研究了早熟禾生长和养分吸收变化。结果表明:K3与K1相比,在7~10月有利于提高早熟禾干物质积累量、含水量、叶绿素a、叶绿素b和类胡萝卜素含量,显著提高了植株氮、磷、钾吸收量;K3与K2相比,在8~9月显著提高了干物质积累量,7月和10月显著提高了叶绿素b和类胡萝卜素含量,8~10月提高了氮磷钾养分吸收量;K3与K4相比,在7~9月提高了干物质积累量,7~10月显著提高了叶绿素b和类胡萝卜素含量,促进了氮磷钾营养元素的吸收。综合分析认为,硝酸钾配施发酵饼肥为适宜施肥处理。

马铃薯钾镁互作效应研究进展

针对马铃薯生产中钾、镁肥配施不合理,钾、镁养分互作调控关系缺乏系统清晰认识的问题,本文结合国内外研究报道,系统综述了钾、镁元素交互效应对马铃薯生长发育与形态建成、养分吸收与运移、块茎产量与品质形成的影响,深入分析了适合马铃薯生长的土壤K+/Mg2+比值范围,提出了马铃薯优质高产与养分高效协同提升的钾、镁互作研究发展方向,以期为马铃薯钾、镁肥的合理施用提供参考。

施钾量对玉米钾素吸收、转运及产量的影响

为研究玉米群体干物质、产量、养分吸收转运对钾素的响应。于2018—2019年在宁夏银川平吉堡开展田间试验,设6个钾肥用量,依次为0、60、120、180、240、300 kg/hm^(2)。结果表明:施钾显著提高了玉米干物质积累、钾素吸收转运及利用效率,以施钾量为180 kg/hm^(2)条件下最好,成熟期干物质积累量较对照提高了3.04%~13.80%,穗钾素积累量较对照提高32.17%~42.57%。施钾处理下钾素转运量提高了20.28%~68.73%,钾转运率提高了10.16%~30.37%,转运养分对籽粒贡献率提高了20.40%~67.71%。180 kg/hm^(2)较其他施钾处理,钾素吸收利用效率提高了20.09%~247.97%,钾素农学利用率提高了37.47%~221.27%,产量提高了6.99%~18.14%。综合考虑玉米产量、养分积累与转运及肥料利用等因素,本试验条件下以施钾量为180 kg/hm^(2)较为适宜。

优化施肥对鲜食型甘薯产量、养分利用及土壤性质的影响

为实现鲜食型甘薯提质增效,本试验以‘烟薯25’为供试品种,设置不施肥、习惯施肥、优化施肥、优化施肥+有机肥4个不同处理,研究不同施肥处理对土壤养分及‘烟薯25’的产量效应、干物质分配、氮磷钾吸收利用情况。结果表明:施肥措施可以有效提高土壤养分含量,优化施肥+有机肥处理显著提升‘烟薯25’的单薯重和鲜薯产量,促进生物产量向甘薯块根转运及干物质向块根分配,提高茎叶、块根及总生物量的氮、磷、钾积累量,且氮、钾的产块根效率和收获指数较习惯施肥均有显著性提高。

氮钾肥施用次数对夏直播棉花干物质积累、产量和养分利用率的影响

【目的】探究氮钾肥施用次数对棉花的影响,为进一步提高长江流域棉区夏直播棉花产量提供参考。【方法】于2021―2022年开展大田试验,采用裂区设计,主区为钾肥(210 kg·hm^(-2))施用次数:K1[播种前(PP)100%]和K2[PP 50%+见花(FF)0 d 50%];副区为氮肥(210 kg·hm^(-2))施用次数:N2[PP 20%+FF 0 d 80%]、N3[PP 20%+FF 0 d 60%+FF 21 d 20%]和N4[PP 10%+FF 0 d 50%+FF 7 d 30%+FF 21 d 10%]。分析不同处理对棉花干物质积累与分配、氮钾积累与分配、产量及其构成因素和养分利用率的影响。【结果】K2N3处理下棉株和源、流、库器官拔秆期的干物质质量和氮、钾积累量以及干物质快速积累期的持续时间和平均积累速率均低于K2N4处理,但干物质以及氮钾向库器官的分配比例较K2N4处理高。K2N3处理可获得较高的籽棉产量和皮棉产量,较K1N2处理(产量最低)分别显著提高31.4%和31.9%,进一步增加施氮次数(K2N4处理)没有显著提高棉花产量。K2N3和K2N4处理的氮肥和钾肥偏生产力无显著差异,但二者均显著高于其他处理。主成分分析结果显示棉花产量的差异主要来源于铃数,促进干物质和氮钾养分向库器官分配有利于提高棉花产量。【结论】长江流域棉区麦后直播棉花,2次施钾配合3次施氮能促进棉株对氮钾的吸收,促进干物质和氮钾养分向库器官分配,增加铃数,提高棉花产量。

“3414”配方施肥对魔芋产量、品质及肥料利用率的影响

探究氮磷钾配施对陕南地区魔芋生长的影响,为魔芋提供科学施肥参考依据。以‘安魔128’为试验材料,采用“3414”施肥方案研究不同水平的氮磷钾配施条件下魔芋出苗率、发病率、产量及养分利用率的变化。结果表明,随着氮、磷、钾施用量的增加,氮肥、磷肥、钾肥的偏生产力均呈现逐渐降低趋势。且肥料农学效率和偏生产力均表现为P>K>N。综合各项指标来看,N_(1)P_(1)K_(2)处理,即127.5 kg/hm^(2)N+54 kg/hm^(2)P_(2)O_(5)+135 kg/hm^(2)K_(2)O的施肥配比较为理想,最为适合在当地推广。

Impact of Nitrogen, Phosphorus and Potassium on Brown Planthopper and Tolerance of Its Host Rice Plants

The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH and its host rice plants. Biochemical constituents of BPH and rice plants with varying nutrient levels at different growth stages,and changes in relative water content(RWC) of rice plants were determined in the laboratory. Feeding of BPH and the tolerance of rice plants to BPH with different nutrient levels were determined in the nethouse. Concentrations of N and P were found much higher in the BPH body than in its host rice plants,and this elemental mismatch is an inherent constraint on meeting nutritional requirements of BPH. Nitrogen was found as a more limiting element for BPH than other nutrients in rice plants. Application of N fertilizers to the rice plants increased the N concentrations both in rice plants and BPH while application of P and K fertilizers increased their concentrations in plant tissues only but not in BPH. Nitrogen application also increased the level of soluble proteins and decreased silicon content in rice plants,which resulted in increased feeding of BPH with sharp reduction of RWC in rice plants ultimately caused susceptible to the pest. P fertilization increased the concentration of P in rice plant tissues but not changed N,K,Si,free sugar and soluble protein contents,which indicated little importance of P to the feeding of BPH and tolerance of plant against BPH. K fertilization increased K content but reduced N,Si,free sugar and soluble protein contents in the plant tissues which resulted in the minimum reduction of RWC in rice plants after BPH feeding,thereby contributed to higher tolerance of rice plants to brown planthopper.

Preparation of soil nutrient amendment using white mud produced in ammonia-soda process and its environmental assessment

A novel method to prepare soil nutrient amendment by calcining a mixture of white mud and potassium feldspar and its environmental assessment were investigated.Under the optimal conditions of a blending mass ratio of 70-30 for white mud to potassium feldspar,a calcination temperature of 1 000℃,a calcination time of 1.5 h and spherulitic diameter of 2.0 cm,the calcined product,as a soil nutrient amendment,could be prepared with the following nutrient composition(mass fraction):K2O 4.16%,CaO 23.43%,MgO 5.04%,SiO2 22.92%,SO4 2-3.71%,and Cl -3.87%in 0.1 mol/L citric acid solution.The concentrations of heavy metals in the calcined product and the emission concentrations of harmful gases from a mixture of white mud and potassium feldspar during calcination process could qualify the National Standards without causing secondary environmental pollution.

Nutrient uptake requirements with increasing grain yield for rice in China

Improved estimates of nutrient requirements for rice （Oryza sativa L.） in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative influences, especially under high-yielding intensive systems. A database involving rice grain yields, nutrient concentrations and accumulations collected from on-field station experiments in the literatures published from 2000 to 2013 in China was developed to understand the relationships between grain yields and plant nutrient uptakes, and to quantify nutrient requirements for different yield levels. Considering all data sets, rice grain yield ranged from 1.4 to 15.2 t ha^-1 with the mean value of 7.84 t ha^-1, and ca. 10.4% of yield observa- tions were higher than the yield barrier level of 10 t ha^-1. N requirement to produce one ton grain was 21.10 kg for the yield range 〈4.0 t ha^-1 with a high variation of 45.8%. Except of the yield range 〈4.0 t ha^-1, the values of N requirement, firstly increased from 18.78 kg for yield range 4.0-5.5 t ha^-1 to 20.62 kg for yield range 7.0-8.5 t ha^-1, then decreased slightly to 19.67 and 19.17 kg for the yield range 8.5-10 and 〉10 t ha^-1, respectively. Phosphorus （P） and potassium （K） requirements showed increasing trends, from 3.51 and 19.87 kg per t grain for 〈4.0 t ha^-1 yield range to 4.10 and 21.70 kg for 〉10.0 t ha^-1 range. In conclusion, nutrient requirement varied with increasement of grain yield, and N, P and K presented various response trends, increasing, declining or stagnating, which would be of great benefit for improving fertilizer strategies.

Optimizing Nutrient Use Efficiency and Returns from Soybean Production under Smallholders in Three Agro-Ecologies of Malawi

Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer rates on rain use efficiency (RUE), harvest index, agronomic use efficiency of phosphorous (AEP) and potassium (AEK), and value cost ratio (VCR) were evaluated. The applied diagnostic PK fertilizer rates significantly improved soybean grain yields, harvest index, rainwater use efficiency, AEP, AEK and returns to fertilizer use expressed as value cost ratio (VCR). However, the results differed significantly

Effect of K and Al on Growth and Nutrient Uptake of Rice

The effects of K and Al in K-deficient and complete nutrient solutions on the growth and nutrient uptake of rice were studied in the work. The effect of Al on the growth of roots and above-ground part of rice was associated with the concentration of Al in solution. A low level (0.1 mmol L-1) of Al promoted but a high level (1 mmol L-1) of Al inhibited the growth of both the root and the aerial part of rice, and the magnitude of K concentration in the nutrient solution also had an appreciable impact on this. Thus, in the low-Al solution, the plant treated with K2 (80 mg K L-1) produced much longer roots, showing the presence of interaction between Al and K; in the high-Al solution the K-treated plant had more and longer roots and a considerably greater dry weight of the above-ground pat compared with the plant deficient in K, showing the alleviating effect of K+ on Al toxicity.The mechanism of the Al-K interaction affecting the rice aerial part growth is not yet known, but part of the reason might be that the excessive amount of Al inhibited the uptake of some nutrients such as Ca and Mg and reduced their transfer to the plant aerial organs, whereas K showed its compensating effect on this; therefore, K could relieve Al toxicity at a high level of Al and promoted rice growth at a lOw level of Al.

High Potassium Aggravates the Oxidative Stress Inducedy by Magnesium Deficiency in Rice Leaves

Magnesium(Mg) deficiency in plant affects photosynthesis and many other metabolic processes.Rice(Oryza sativa L.cv.'Wuyunjing 7') plants were grown in hydroponics culture at three Mg and two potassium(K) levels under greenhouse conditions to examine the induction of oxidative stress and consequent antioxidant responses in rice leaves due to Mg deficiency.At low Mg(0.2 mmol L-1 Mg supply for two weeks after transplanting) and high K(6 mmol L-1) for 21 days,the rice plants showed severe Mg deficiency and a significant decreases in the dry matter production.The Mg deficiency in leaves decreased chlorophyll concentrations,photosynthetic activity,and soluble protein,but significantly increased the concentrations of soluble sugars and malondialdehyde(MDA) and the activities of superoxide dismutase(SOD,EC 1.15.1.1),catalase(CAT,EC 1.11.1.6) and peroxidase(POD,EC 1.11.1.7).In addition,Mg concentrations in the leaves and in the shoot biomass were negatively related to the activities of the three antioxidative enzymes and the concentration of MDA in leaves.There were very significant interactive effects between Mg and K supplied in the culture solution on shoot biomass yield,chlorophyll content,photosynthesis rate,the activities of SOD,CAT and POD,and MDA content in the leaves of rice.It is suggested that the high K level in the nutrient solution aggravated the effect of low Mg supply-induced Mg deficiency and created the oxidative damage in rice plants.

Transgenic approaches for improving use efficiency of nitrogen, phosphorus and potassium in crops

The success of the Green Revolution largely relies on fertilizers, and a new Green Revolution is very much needed to use fertilizers more economically and efficiently, as well as with more environmental responsibility. The use efficiency of nitrogen, phosphorus, and potassium is controlled by complex gene networks that co-ordinate uptake, re-distribution, assimilation, and storage of these nutrients. Great progress has been made in breeding nutrient-efficient crops by molecularly engineering root traits desirable for efficient acquisition of nutrients from soil, transporters for uptake, redistribution and homeostasis of nutrients, and enzymes for efficient assimilation. Regulatory and transcription factors modulating these processes are also valuable in breeding crops with improved nutrient use efficiency and yield performance.

Testing potassium limitation on soil microbial activity in a sub-tropical forest

Because potassium(K)is a rock-derived essential element that can be depleted in highly-weathered tropical soils,K availability may limit some portion of soil microbial activity in tropical forest ecosystems.In this paper we tested if K limits microbial activity in the condition of sufficient labile C supply.An incubation experiment was performed using surface soil samples(0–10 cm depth)obtained from four permanent ecological research plots in a natural sub-tropical forest in southern China.Soil samples were taken in September 2016.Heterotrophic soil respiration rates and microbial biomass were measured after the addition of glucose(both D and L)with and without K(potassium chloride).We did not observe any effects of K addition on soil microbial respiration,suggesting that K does not limit the microbial activity in the condition of sufficient labile C supply.The lack of microbial response to added K can be attributed to the high mobility of K in forest ecosystems,which may have provided sufficient K to microbes in our soil samples(already provided at the beginning of the incubation).However,at the present stage,we cannot conclude that K is not a limiting factor of soil microbial activity in other tropical forest ecosystems because of the heterogeneity of tropical forest ecosystems and few observations.The hypothesis needs to be tested in larger numbers of tropical forests.

不同粒型花生品种氮磷钾养分积累动态研究

为明确不同粒型花生品种氮磷钾养分吸收动态及模式,在大田试验条件下,以大粒型花生品种花育22、中粒型花生品种花育20和小粒型花生品种农花16为试材,采用完全随机设计,研究了不同粒型花生品种氮磷钾养分积累量、积累最快时间、吸收最大速率及产量。两年试验结果表明:各生育时期大粒型花生品种植株和荚果的氮磷钾素积累量均最高,中粒品种次之,成熟时大粒品种平均分别比小粒品种高61.63%、60.37%、47.64%和77.97%、91.49%、86.74%,中粒品种分别比小粒品种高46.53%、50.99%、38.32%和63.53%、73.37%、77.92%;籽仁中氮磷钾含量亦表现为大粒品种>中粒品种>小粒品种;不同粒型花生品种氮磷钾素积累量符合“S”型生长曲线特征,小粒型品种氮素和磷素积累最快时间出现较早,2016年和2017年分别为出苗后58 d、65 d和53 d、81 d,大粒型品种则钾素积累最快时间较早,平均为出苗后54 d。大粒型和中粒型品种氮素和钾素最大积累速率均高于小粒型品种;大、中、小粒品种磷素最大积累速率平均分别为2.59,2.57,2.21 mg·plant^(-1)·d^(-1),3个品种之间差异未达到显著水平。大粒型品种百果重和百仁重均最大,分别为195.47 g、219.63 g和76.57 g、85.53 g,大粒型产量最高,达到5300.00 kg·hm^(-2),中粒型品种次之,为4744.44 kg·hm^(-2),小粒型品种产量最低,仅为4713.89 kg·hm^(-2),后两者分别比大粒型品种低10.48%和11.06%,且与大粒型品种均达到了差异显著水平(p<0.05)。

沂南县典型设施蔬菜施肥现状调查与分析

为明确山东沂南地区典型设施蔬菜的施肥现状及存在问题,以沂南县辛集镇、大庄镇、张庄镇、依汶镇、界湖街道、苏村镇和砖埠镇为调查区域,采用问卷调研和田间取样的方法,对设施番茄和黄瓜产量及施肥情况进行调查分析。结果显示,日光温室黄瓜平均产量是塑料大棚黄瓜平均产量的1.58倍,设施黄瓜产量要明显高于设施番茄的产量;塑料大棚黄瓜、日光温室黄瓜和日光温室番茄的N、P_(2)O_(5)和K_(2)O平均投入量分别为玉米的2.85~4.68、5.10~8.54倍和5.90~10.02倍;且塑料大棚黄瓜、日光温室黄瓜和日光温室番茄的N、P_(2)O_(5)和K_(2)O投入量分别是需求量的1.46~2.41、3.36~7.03、0.92~1.35倍。氮磷钾养分供应比例与蔬菜需求比例不匹配,钾元素相对平衡,而氮磷明显供应比例过高;同种蔬菜在相同种植方式下,不同区域之间氮磷钾养分投入量差异明显;基肥和追肥的养分占比不合理,基肥比例过高,尤其基施有机肥的养分占比超过了60%。因此,建议农户减少氮磷肥的投入,适当降低基肥中的有机肥占比,适当提高化肥追施的比例,根据蔬菜的种类和生育期选择适合的化肥种类。

Relationship between Ponkan Mandarin Fruit Quality and Nutrient Concentrations

Five age groups of trees were carried out in order to study relationships between the deterioration of Ponkan mandarin fruit quality and changes in tissues nutrient concentrations with tree age.Fruit quality and nutrient concentrations in fruits and leaves were measured.Comprehensive fruit quality decreased in the order:5-year-old > 13-year-old > 38-year-old > 8-year-old >18-year-old.In 18-year-old trees,calcium(Ca) concentrations of fruit and leaf were lower,while potassium(K) and boron(B) concentrations of fruit and magnesium(Mg) and manganese(Mn) concentrations of leaf were higher.Negative relationships were observed between fruit total soluble solids and leaf B,while positive relationships were observed between fruit total soluble solids and leaf and fruit Ca concentrations,and between titratable acidity and leaf Mn.Fruit quality decreasing with tree age most likely resulted from an imbalance of high K,Mg and B but lower Ca concentrations in leaves and fruits.

不同营养液氮钾比对高品质番茄生长和品质的影响

为明确适宜京郊早春茬塑料大棚高品质番茄的营养液氮钾比,共设置4个氮钾比(1∶1.2、1∶1.5、1∶1.8、1∶2.1)处理,分析其对番茄植株、果实性状、品质、产量等的影响。结果表明:随着钾含量的增加,株高、株高日平均生长速率、叶片数、叶片日平均生长片数均表现先升高后降低,在氮钾比1∶1.5达到峰值。果实横径、纵径、可溶性固形物含量、总糖含量、糖酸比都是随着钾含量的增加先增高再降低,在氮钾比1∶1.8达到峰值,其中可溶性固形物含量、总糖含量、糖酸比的峰值分别为7.47%、7.03%、7.96。不同处理的单穗坐果数、小区产量、折合667m^(2)产量、折合商品果667 m^(2)产量差异均达显著水平,在氮钾比1∶1.5达到最大峰值,其中折合667 m^(2)产量、折合商品果667 m^(2)产量的峰值分别为2984.3、2583.5 kg。氮钾比1∶1.5的脐腐果比例最低,为13%,比其他处理降低6~8百分点。在生产上需要根据生产目的调整营养液氮钾比,氮钾比1∶1.5能够满足追求产量的需要,氮钾比1∶1.8能够兼顾追求产量和品质的需求。