包膜氯化钾一次基施对棉花生长周期钾素供应、 产量及品质的影响

【目的】钾是影响棉花生长发育和纤维品质的重要因素,本文旨在探究一次基施控释钾肥对棉花产量、 品质和钾肥利用率的影响,为棉花合理施用钾肥提供理论依据。【方法】以国欣棉3号为试验材料,在氮磷肥相同的条件下,连续2年盆栽试验。设6个处理: 1)不施钾肥(CK); 2)一次基施普通氯化钾(KCl); 3)40%基施+60%初花期追施氯化钾(KClD); 4)一次基施硫酸钾(KS); 5)40%基施+60%初花期追施硫酸钾(KSD); 6)一次基施控释氯化钾(CRK),每个处理重复四次。测定了苗期、 蕾期、 初花期、 盛花期、 始絮期和收获成熟期土壤速效钾含量和棉花株高、 茎粗,调查了籽棉产量,分析了品质指标和钾素吸收量。【结果】控释钾肥一次性基施(CRK)较普通钾肥显著提高了初花期、 盛花期、 始絮期及收获期的土壤速效钾含量。CRK较KCl处理增产23.6%,比KS处理增产15.6%,比KClD处理增产16.0%,与KSD处理差异不显著。CRK较KCl处理显著提高了衣分值,其余处理间单铃重及衣分差异不显著。CRK显著提高纤维长度、 伸长率和断裂比强度,但马克隆值和整齐度与其他处理差异不显著。速效钾肥追施较一次基施处理显著增加了生物量和吸钾量,但均低于控释钾肥处理。CRK处理的钾素利用率较KCl处理显著提高41.9%~50.9%,较KS处理提高27.3%~29.9%,较KClD处理提高21.1%~25.2%。【结论】本试验采用的控释钾肥钾素释放高峰期(80~110天)与棉花养分吸收高峰基本吻合,在棉花上一次基施对不同生育期的钾素供应优于普通钾肥一次性基施,也好于普通钾肥基施加追施,较速效钾肥显著提高了棉花的产量、 品质和钾肥利用率。     

二种钾肥对海泡石钝化修复镉污染土壤效应影响的研究

为了揭示钾肥对Cd污染土壤钝化修复效果的影响,为土壤钝化修复过程中合理施钾肥提供理论依据。本文选取不同剂量(含量以K2O计算,分别为0.1 g·kg~(-1)、0.2 g·kg~(-1)和0.3 g·kg~(-1))的KCl和K_2SO_4作为典型钾肥,以海泡石(10 g·kg~(-1))作为钝化材料,通过油菜盆栽试验,研究了两种钾肥在海泡石钝化条件下对Cd污染土壤修复效应的影响。结果表明:K_2SO_4显著增加了油菜的生物量,其增幅为6.06%~10.05%。与单施海泡石钝化相比,在海泡石钝化时施用KCl和K_2SO_4两种钾肥,油菜地上部茎叶Cd含量分别增加16.38%~60.73%和15.62%~25.19%;施用KCl和K_2SO_4对土壤p H未产生显著性影响,却显著地增加了土壤有效态Cd含量,其增幅分别为25.51%~34.65%和18.5%~24.96%。添加海泡石可使土壤的Zeta电位向负值方向移动,提高土壤对Cd的负载能力;但添加海泡石下施用KCl和K_2SO_4均能提高土壤的Zeta电位,降低土壤对Cd的负载能力。等温吸附试验同样表明,添加KCl和K_2SO_4均能降低海泡石对Cd的吸附量,在水溶液中海泡石对Cd的最大吸附量为5.30 mg·kg~(-1),添加KCl和K_2SO_4后吸附量分别降低至2.87 mg·g~(-1)和4.92 mg·g~(-1)。KCl和K_2SO_4显著改善了土壤中K、Mn、Cu和Zn等营养元素的有效态含量。从上述结果可以发现,在海泡石钝化修复Cd污染土壤过程中,施K_2SO_4对钝化效果的影响小于施KCl。     

Evaluation of cement kiln flue dust as a potassium and sulfate fertilizer

Abstract

The main objective of this study was to determine the efficacy of cement kiln flue dust as a substitute for potassium sulfate fertilizer. Chemical and X‐ray diffraction analyses revealed that the flue dust contained about 20.7% K of which 9.1% was present as aphthitalite (K₃Na(SO₄)₂) , 4.4% as sylvite (KCl) and the remaining 7.2% as arcanite (K₂SO₄) . Accordingly, about 80% of the potassium in the dust was present as sulfates, though it contained 30% total sulfate and 15% Ca.

The effects of flue dust were compared to some or all of the following fertilizers: KCl, K₂SO₄ and a synthetic fertilizer, on 11 soils ranging in texture from sand to clay in three greenhouse experiments. The synthetic fertilizer was made from K₂SO₄ and CaSO₄.2H₂O which were applied at the same rate of K and Ca as contained in the flue dust. The experimental results show that flue dust is as effective a K source as any of the fertilizers tested as it increased potato, barley and alfalfa yields and tissue and soil K concentrations to the same level. Furthermore, the flue dust increased the tissue sulfur concentration and the quantities of available sulfate in soils to the same level as potassium sulfate. Finally, the Ca contained in flue dust increased the concentration of this element in potato tops and soils when grown on eight coarse textured soils. The flue dust had, however, no effect on soil pH on any of the soils tested.     

Genotypic variation of potassium uptake and use efficiency in cotton (Gossypium hirsutum)

Potassium (K) deficiency is one of the main limiting factors in cotton (Gossypium hirsutum L.) production. To study the mechanism of high K‐use efficiency of cotton, a pot experiment was conducted. The experiment consisted of two cotton genotypes differing in K‐use efficiency (H103 and L122) and two K‐application levels (K₀: 0 g (kg soil)^–1; K₁: 0.40 g (kg soil)^–1). Root‐hair density and length, partitioning of biomass and K in various organs, as well as K‐use efficiency of the two cotton genotypes were examined. The results show that there was no significant difference in K uptake between the two genotypes at both treatments, although the genotype H103 (high K‐use efficiency) exhibited markedly higher root‐hair density than genotype L122 in the K₁ treatment. Correlation analysis indicates that neither root‐hair density nor root‐hair length was correlated with plant K uptake. Furthermore, the boll biomass of genotype H103 was significantly higher than that of genotype L122 in both treatments, and the K accumulation in bolls of genotype H103 was 39%–48% higher than that of genotype L122. On the other hand, the litter index (LI) and the litter K‐partitioning index (LKPI) of genotype H103 were 14%–21% and 22%–27% lower than that of genotype L122. Lastly, the K‐use efficiency of total plant (KUE‐P) of genotype H103 was comparable with that of genotype L122 in both treatments, but the K‐use efficiency in boll yield (KUE‐B) of genotype H103 was 24% and 41% higher than that of genotype L122 in K₀ and K₁ treatments. Pearson correlation analysis indicated that KUE‐P was positively correlated with BKPI and negatively correlated with LKPI, while KUE‐B was positively correlated with BKPI and boll‐harvest index (HI_B), and negatively correlated with LKPI. It is concluded that there were no pronounced effects of root‐hair traits on plant K uptake of the two genotypes. The difference in K‐use efficiency was attributed to different patterns of biomass and K partitioning rather than difference in K uptake of the two genotypes.     

5年定位试验条件下钾肥用量对双季稻产量和施钾效应的影响

通过5年定位试验（2008~2012年）, 研究不同钾肥施用量对水稻产量、植株钾素含量、钾素积累量、钾肥利用率、土壤钾素含量、钾素平衡和钾肥经济效益的影响。试验施钾量（K2O）从低到高设K0（不施钾）、K1（早稻84 kg/hm2、晚稻105 kg/hm2）、K2（早稻120kg/hm2、晚稻 150 kg/hm2）、K3（早稻156kg/hm2、晚稻195 kg/hm2）和K4（早稻192kg/hm2、晚稻 240kg/hm2）5个处理。5年的试验结果表明, 施钾能显著提高早、晚稻产量,在一定施钾量范围内,水稻产量随施钾量的增加而增加;施钾能促进水稻植株对钾素的吸收和积累,尤其是稻草对钾素的吸收和积累;早、晚稻的钾肥农学效应均以K2处理最高（早稻3.12 kg/kg、晚稻3.70 kg/kg）;钾肥利用率以K1处理最高（早稻41.2%、晚稻76.4%）,并随施钾量提高而降低;不同施钾量对土壤钾素含量有明显影响,土壤速效钾、缓效钾和土壤全钾均随施钾量的增加而增加,且不同处理间土壤速效钾含量差异达极显著水平（P＜0.01）;连续种植5年10季水稻后,K0、K1和K2处理的土壤钾素亏缺（K 127.1kg/hm2、 58.3kg/hm2和10.8kg/hm2）,亏缺量随施钾量的增加而降低; K3和K4处理的土壤钾素盈余（48.0 kg/hm2 和109.2kg/hm2）,盈余量随施钾量的增加而增加。在经济效益上,早、晚稻产投比均以K2处理最高（早稻1.04、晚稻1.27）。综合考虑施钾的增产效应、经济效益和土壤钾素养分平衡等因素,建议该双季稻区早稻施钾量在K2O 120~156 kg/hm2、晚稻施钾量在K2O 150~195kg/hm2范围内较为适宜。     

Effect of foliar fertilization of potassium on yield,quality, and nutrient uptake of groundnut

Abstract

Groundnut (Arachis hypogae L.) is the most important oilseed crop of India and it is abundantly grown under rainfed conditions in vertisols of Western India. The objective of this work was to study the effect of potassium (K) basal and foliar fertilization on yield, nutrient concentration in tissue and quality parameters of groundnut. Two varieties, GAUG‐1 (bunch type) and GAUG‐10 (spreading type) were grown during Kharif (rainfed) and Rabi (irrigated) seasons at Junagadh, Gujarat. The experiment compared two foliarapplied K fertilizers (KCl and K₂SO₄) at two different doses (0.5 and 1.0%) with basal KCl application (0 and 50 kg K₂O ha^?1). Field soil was highly calcareous (pH 8.2, NH₄OAc extractable K 188 kg ha^?1 with 40% lime reserve) Vertic ustochrept. The results showed a significant response in pod yield with foliar and soil‐applied potassium as compared to the control treatment. Pod yields were significantly higher when basal and foliar applications were combined. The best results were achieved with foliar application of 1% KCl together with a basal fertilization with 50 kg K₂O ha^?1. Response to foliar‐applied K was higher in rainfed kharif crop than in irrigated rabi crop. Groundnut variety GAUG‐10 out yielded GAUG‐1. Foliar K application increased plant tissue concentration of K. Foliar fertilization with KCl and K₂SO₄ did not cause leaf burn. Potassium application improved the crop harvest index and grain quality parameters of boldness, protein and oil contents. Response to K in quality parameters of protein and oil contents of seed was more consistent with foliar applied K₂SO₄ . The results confirmed that the practice of foliar K nutrition when used as a supplement and not a substitute for standard soil fertilization, is beneficial for groundnut crop in Western India.     

不同钾肥对再生水灌溉条件下土壤-作物系统Cd的影响

为了探明再生水灌溉条件下不同施钾肥处理对土壤-作物系统Cd的影响及差异性,通过田间微区试验研究了不同施钾肥处理对再生水灌溉番茄植株、果实以及根际土与非根际土Cd含量的影响。结果表明:再生水灌溉条件下,施钾肥处理可提高番茄果实产量,施加KCl较K2SO4增产效果明显,分别较不施肥处理可增产6.10%～24.00%和1.36%～13.16%;不施钾肥较不施肥处理番茄果实Cd含量降低,但降低幅度小于施加钾肥处理,施加KCl较K2SO4处理番茄果实Cd含量较低,Cd含量分别较不施钾肥处理分别减少58.33%和8.33%,且各处理均未超0.05mg/kg的限值标准;不施钾肥处理较不施肥处理土壤pH、Cd含量有所降低,降低幅度小于施钾肥处理,有效态Cd有所增加,施加KCl和K2SO4较不施肥处理有效态Cd降低,施加KCl和K2SO4较不施钾肥处理根际土和非根际土pH、Cd含量和有效态Cd含量均有所降低,其中施加KCl根际土和非根际土Cd含量分别降低2.96%～3.11%和5.75%～14.22%,施加K2SO4分别降低4.14%～5.90%和8.10%～8.29%;施加KCl根际土和非根际土有效态Cd含量分别降低10.75%～16.19%和13.98%～28.74%,施加K2SO4分别降低15.97%～20.55%和19.91%～24.70%。因此,再生水灌溉条件下,可通过选择施加适宜的钾肥种类,调控重金属Cd在土壤-作物系统的分布及其生物有效性,施加K2SO4较KCl相比,可一定程度降低土壤Cd全量及有效态Cd含量。     

Current potassium‐management status and grain‐yield response of Chinese maize to potassium application

The great achievement of the development of intensive in agriculture in China can be partly attributed to substantial increases in mineral‐nutrient application. However, whereas farmers tend to apply high levels of nitrogen (N) and phosphorus (P) application of potassium (K) has been neglected. A greater understanding of the relationship between maize (Zea mays L.) grain yield and K‐application rate is thus required to provide an improved rationale for K fertilization for farmers in the various agro‐ecological regions of China. In this study, a total of 2765 farmers' survey data and 3124 on‐farm experiments across major maize agro‐ecological regions in China were collected and evaluated for farmers' K‐management status and to determine grain‐yield response to K application. Nationally, the average K‐application rate on farms was 26 kg K ha^–1 and varied from 0 to 158 kg K ha^–1, with a coefficient of variation of 107%, but the applied K‐fertilizer rates were not related to grain yield. Maize grain yields at recommended K rates increased by 14.0%, 14.7%, 19.4%, and 4.3% in Northeast China, North China Plain, Southwest China, and Northwest China, respectively, compared to zero K fertilization (K₀). Increased yield due to K fertilization (IY_max, difference between maximum yield across all treatments and K₀‐treatment yield for each experiment) averaged 1.4 t ha^–1 but varied widely in different agro‐ecological regions. Soil extractable K (NH₄OAc‐K) and intercounty variation resulted in large variation in IY_max in agro‐ecological regions, as did other factors, such as use of particular maize hybrids, soil types, or years in different regions.     

Effect of Potassium Fertilizers on Cotton Yield and Nitrogen Uptake Efficiency in an Aridisol

A field experiment was carried out to study the effect of different rates of potassium (K) fertilizer [0, 50, 100, and 150 potassium oxide (K₂O) ha^–1] in the presence of increased supply of nitrogen (N) (120, 180, and 240 kg N ha^–1) on cotton (Gossypium hirsutum L.) yield and the N and K use efficiencies using the ¹⁵N isotopic dilution technique. Potassium fertilizer increased cotton yield, which was significant and more pronounced with the application of N in the high level (N3). The greatest cotton yield (6442 kg ha^–1) was obtained in N2K3 treatment with an increase of 14% over the control. In addition, K fertilizer significantly increased N uptake efficiency in the N2 and N3 treatments. The greatest N uptake efficiency (98%) was in N2K3 treatment. The greatest K uptake efficiency (42%) was occurred in N3K1 treatment. In conclusion, the use of K fertilizer could be useful when growing cotton in soils of moderate to high N content to improve N uptake efficiency and consequently increase cotton yield.     

有机无机复混肥优化化肥养分利用的效应与机理研究III.有机物料与钾肥复混对玉米产量及肥料养分吸收利用的影响

【目的】将有机物料与化学钾肥按不同比例复混制成有机无机复混钾肥,研究其对优化化肥钾的吸收利用效应和机理,可为复混肥的科学应用提供依据。【方法】以味精厂制糖形成的糖渣作为有机原料,与硫酸钾按照3:1、1:1、1:3(w/w)比例复混,采用团粒法制成含钾量分别为K2O 12.2%、24.7%和37.3%的有机无机复混钾肥。采用土柱栽培方法,设置K2O低(75 kg /hm2)、中(150 kg /hm2)、高(225 kg /hm2) 3个施钾水平,每个施钾水平下,采用不同含钾量的有机无机复混钾肥为供试肥料,以硫酸钾为对照,同时设置与钾处理等量的糖渣施用量处理作为对照,以消除有机物料可能带来的影响。以玉米为供试作物,玉米收获后,分别测定叶片、茎鞘、籽粒中的含钾量,并根据生物量计算钾的累积量和化肥钾的利用率。【结果】1)低钾、高钾水平下,复混钾肥比硫酸钾处理分别增产27.75%和10.77%;而中钾水平下,复混钾肥没有表现出明显的增产效果;低钾、中钾和高钾水平,复混钾肥玉米植株籽粒平均产量较硫酸钾增产11.36%。2)低钾、高钾水平下,复混钾肥玉米植株钾素吸收量比硫酸钾处理分别提高31.32%和16.11%;中钾水平下,复混钾肥植株钾素吸收量较硫酸钾处理没有明显增加;有机无机复混钾肥处理在低钾、中钾和高钾水平下的植株平均吸钾量较硫酸钾处理提高11.43%。3)低钾、中钾、高钾水平复混钾肥玉米植株平均吸钾量较等量有机物料处理提高11.92%,而硫酸钾处理较不施钾肥的对照处理(CK)仅提高3.31%,有机物料与钾复混后,显著提高了玉米植株吸钾量。4)低钾、高钾水平下,复混钾肥的平均化肥钾表观利用率比硫酸钾有所提高;中钾投入水平下,复混钾肥处理钾的表观利用率与硫酸钾处理基本相同;低钾、中钾和高钾水平,复混钾肥平均钾素表观利用率比硫酸钾处理提高17.92个百分点。【结论】有机物料与硫酸钾复混,可以优化硫酸钾的肥效和玉米对其中钾的吸收利用。综合考虑玉米产量和钾肥利用率,糖渣与硫酸钾的适宜复混比例可定为1:3(w/w),其施用量在与本试验类似的土壤条件下应低于硫酸钾的施用量。     

Chloride‐induced leaf breakdown in kiwifruit

The effects of several rates of KCl (0–1500 kg/ha) were compared with K₂SO₄ at the equivalent K rate as 1500 kg/ha KCl on five commercial orchards of kiwifruit (Actinidia deliciosa [A. Chev] C.F. Liang et A.R. Ferguson var. deliciosa cv. Hayward). Leaf breakdown (marginal leaf scorch followed by necrosis and leaf drop) was induced by KCl application at four of the five sites. The symptoms developed at leaf Cl concentrations of 1.5% dry weight and the severity of symptoms increased with leaf Cl concentrations. At another site, a zero K treatment was compared to several rates of KCl (300–1500 kg/ha) and K₂SO₄ applied at equivalent rates of K in factorial combination with two N fertilizer rates. This site had received KCl and developed severe leaf breakdown in the previous season. Leaf Cl concentrations on the zero K and K₂SO₄ treatments were higher in this experiment (1.7–2.1% dry weight) than at the other five experimental sites (0.6–1.3%), and at this site mild leaf breakdown symptoms developed on these treatments. Leaf N concentrations were greater, while leaf Cl concentrations and the severity of symptoms were less at the higher N rate. At all of the experimental sites that developed leaf breakdown symptoms, the severity of symptoms increased with the rate of KCl application and were significantly correlated to leaf Cl concentrations but not other leaf nutrient concentrations.     

钾营养对棉花苗期生长和叶片生理特性的影响

在田间试验条件下,研究了施钾对棉花苗期生长和功能叶片生理特性的影响。试验设2个品种,4个施钾量。结果表明,施钾增加了棉花株高和单株叶片数,而对单株叶面积的影响不同,当施钾(K2O)量为180.kg/hm2时,叶面积达最大值,继续增施钾肥叶面积减小;施钾促进了叶绿素的合成,同时增加了叶绿素荧光动力学参数Fv/Fo、Fv/Fm和qP值,降低了qN值,增加了PSⅡ的实际量子效率(ФPSⅡ)和光合电子传递速率(ETR),从而提高了棉花功能叶的光合功能;施钾还增加了叶片中生长素(IAA)、玉米素核苷(ZR)、赤霉素(GA3)的含量,降低了脱落酸(ABA)的含量,提高了IAA/ABA、ZR/ABA、GA3     

控释钾肥对大蒜-棉花套作体系产量和土壤钾素供应的影响

于2013-2015年在山东农业大学试验站进行连续3年5季的池栽试验,以硫酸钾基施(CK1)和氯化钾基施(CK2)为对照,探究氯化钾50%基施+50%盛花期追施(KCl D)、氯化钾配施硫磺基施(KCl S)、控释氯化钾基施(CRK)和控释氯化钾配施硫磺基施(CRKS)对棉花各生育期叶片光合特性和土壤速效钾含量变化以及蒜棉套作体系产量的影响,为棉花合理施用钾肥提供理论依据。结果表明,控释氯化钾在土壤中养分释放能够满足棉花各生育期钾素需求。CRKS较普通钾肥基施处理提高了铃期和始絮期土壤速效钾含量,提高了铃期后叶片SPAD值和净光合速率,增加了成铃数和单铃重,皮棉显著增产16.9%~30.9%。CRKS较KCl D和CRK皮棉分别增产12.2%~16.1%和8.7%~10.4%。大蒜蒜薹和鳞茎产量均以CRKS最高,较其余处理分别增产2.8%~27.9%和4.8%~23.5%。CRKS较CK2显著提高了纤维长度、整齐度指数和伸长率。经过3年施肥后,CRKS较普通钾肥基施显著提高了土壤水溶性钾和非特殊吸附钾含量。因此,控释氯化钾配施硫磺在棉花上一次基施代替硫酸钾和氯化钾提高了棉花生长后期土壤钾素供应和有效性,改善了叶片光学特性,提高了棉花产量和品质。     

控释钾肥对玉米产量、钾肥利用率和土壤速效钾的影响

通过玉米—小麦轮作条件下连续2年的大田定位试验,以钾空白(CK)、普通氯化钾常量(K1)、普通氯化钾高量(K2)为对照处理,研究通过控释氯化钾常量(CRK1)、控释氯化钾高量(CRK2)、氯化钾与控释氯化钾等比掺混常量(BBF1)、氯化钾与控释氯化钾等比掺混高量(BBF2)处理对玉米产量、钾肥利用率和土壤速效钾的影响。结果表明:(1)BBF2玉米-小麦季产量分别为11 697.8kg/hm2和11 921.1kg/hm2,增产和增收效果最好,较K1分别显著增产13.3%和15.7%,较K1分别显著增收16.6%和19.6%;(2)BBF2钾肥农学利用率较K1分别显著提高了49.0%和41.9%,生理利用率较K1分别显著提高了17.6%和34.8%;BBF1钾肥表观利用率最高,玉米—小麦分别为23.73%和35.22%;(3)施用钾肥显著提高了玉米的株高和茎粗;BBF2提高了玉米吐絮后期至成熟期的株高;CRK1、CRK2、BBF1、BBF2均提高了玉米吐絮后期叶片SPAD值。本试验条件下,控释氯化钾与普通氯化钾掺混施用可满足玉米整个生育期的钾素需求,提高玉米产量和钾肥利用率,BBF2处理为玉米最佳钾肥施用方案。     

Dry matter accumulation and partitioning in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) as influenced by potassium fertilization

The effect of potassium (K) supply on dry matter accumulation and partitioning of biomass between different among parts of cotton (Gossypium hirsutum L.) was determined under irrigated conditions. The treatments were four cotton cultivars (CIM-448, CIM-1100, Karishma, and S-12), four K rates (0, 62.5, 125, and 250 kg K ha⁻¹), and two K-fertilizer sources (K₂SO₄, KCl). Sequential harvests were collected at four stages of growth, viz first flower, peak flowering, first boll split, and maturity. The dry weights (DW) of vegetative and reproductive organs were determined. Maximum total DW was obtained at 125 days after planting, and then it declined because of leaf senescence at maturity. Cultivars differed significantly among themselves in the production of total DW and its partitioning between different organs. The addition of K fertilizer increased DW substantially at various stages of growth. Potassium fertilizer stimulated cotton plant to translocate resources towards reproductive organs rather than vegetative organs. Crop receiving 250 kg K ha⁻¹ allocated 77% more dry matter into reproductive organs. The K-sources produced a little effect on the allocation of DW in various parts of the plant. Maximum reproductive–vegetative ratio (RVR) was maintained by cv CIM-448 and minimum in cv CIM-1100. Data showed that a shift in DW allocation into reproductive organs was dependent upon sustained supply of K⁺ throughout the season. There were positive significant correlations (0.86, 0.71, and 0.90) between seed cotton yield and total DW, vegetative DW, and reproductive DW, respectively.     

Effect of long‐term fertilization and manuring on potassium release properties in a Typic Ustochrept

A long‐term fertilizer experiment, over 27 years, studied the effect of mineral fertilizers and organic manures on potassium (K) balances and K release properties in maize‐wheat‐cowpea (fodder) cropping system on a Typic Ustochrept. The treatments consisted of control, 100% nitrogen (100% N), 100% nitrogen and phosphorus (100% NP), 50% nitrogen, phosphorus, and potassium (50% NPK), 100% nitrogen, phosphorus, and potassium (100% NPK), 150% nitrogen, phosphorus, and potassium (150% NPK), and 100% NPK+farmyard manure (100% NPK+FYM). Nutrients N, P, and K in 100% NPK treatment were applied at N: 120 kg ha^—1, P: 26 kg ha^—1, and K: 33 kg ha^—1 each to maize and wheat crops and N: 20 kg ha^—1, P: 17 kg ha^—1, and K: 17 kg ha^—1 to cowpea (fodder). In all the fertilizer and manure treatments removal of K in the crop exceeded K additions and the total soil K balance was negative. The neutral 1 N ammonium acetate‐extractable K in the surface soil (0—15 cm) ranged from 0.19 to 0.39 cmol kg^—1 in various treatments after 27 crop cycles. The highest and lowest values were obtained in 100% NPK+FYM and 100% NP treatments, respectively. Non‐exchangeable K was also depleted more in the treatments without K fertilization (control, 100% N, and 100% NP). Parabolic diffusion equation could describe the reaction rates in CaCl₂ solutions. Release rate constants (b) of non‐exchangeable K for different depth of soil profile showed the variations among the treatments indicating that long‐term cropping with different rates of fertilizers and manures influenced the rate of K release from non‐exchangeable fraction of soil. The b values were lowest in 100% NP and highest in 100% NPK+FYM treatment in the surface soil. In the sub‐surface soil layers (15—30 and 30—45 cm) also the higher release rates were obtained in the treatments supplied with K than without K fertilization indicating that the sub‐soils were also stressed for K in these treatments.     

Assessment of economic and environmental impacts of two typical cotton genotypes with contrasting potassium efficiency

It is essential to produce optimal crop yields while reducing adverse environmental impacts of overfertilization. Therefore, nutrient‐efficient plants may play a major role in improving the efficiency of fertilizer use whilst increasing crop yields. This field trial was conducted to study the differences on absorption and utilization of nitrogen (N), phosphorus (P), and potassium (K) of K‐efficient cotton genotype 103 and K‐inefficient cotton (Gossypium hirsutum L.) genotype 122 and their environmental and economic effects. The results show that seed cotton yield was significantly different between K‐efficient cotton genotype 103 and K‐inefficient cotton genotype 122; the yields of genotype 103 were 39.2%, 33.8%, and 25.0% higher than those of genotype 122 with no K fertilizer (K0), 112 kg K ha^–1 K (K1), and 224 kg K ha^–1 (K2), respectively. Even when no K fertilizer was applied, the yield of genotype 103 was still 7.9% higher than the yield of genotype 122 at the highest K level (K2). Further economic benefit analysis revealed that the value cost ratio (VCR) of genotype 103 was significantly higher than 122 at K0 and K1, and harvest index (HI) of genotype 103 was significantly higher than that of genotype 122 at all three K levels. In addition, when fertilized with K, partial factor productivity of applied K (PFP_K) of genotype 103 was dramatically higher than that of genotype 122, demonstrating that genotype 103 had stronger ability to utilize K. Besides, the N‐ and P‐use efficiencies of genotype 103 were also higher than those of genotype 122. It is concluded that: (1) genotype 103 gives better profit than genotype 122 and (2) genotype 103 uses fertilizer more efficiently and reduced fertilizer inputs will alleviate environmental risks.     

两种钾肥对湖北棉区棉花养分吸收及经济效益的影响

通过田间试验研究了钾肥用量(K2O 75、150、225 kg/hm2)与种类对棉花产量、养分吸收及经济效益的影响。结果表明:施硫酸钾与硫酸钾镁都能增加产量,提高养分含量及经济效益,两者相比,在低、中、高3个水平上棉花产量前者比后者分别提高3.5%、3.2%和1.4%;相比硫酸钾镁,施硫酸钾可使棉花对氮、磷的吸收量增加,棉花根的氮含量平均增加13.9%,茎的磷含量平均增加2.7%,但对钾、钙、镁、硫的吸收量影响较少。施用硫酸钾比施用硫酸钾镁所获的效益平均高540元/hm2,且在施K2O 75 kg/hm2处理所获效益最高,比不施钾肥多获效益10 350元/hm2。     

Response of Cotton to Potassium Fertilizer on Effectiveness of Fruiting Sites in Aridisols

Abstract

A field experiment was conducted to assess the effectiveness of fruiting positions along sympodia under varying levels and sources of potassium (K) fertilizer on field-grown cotton in an arid environment. Treatments consisted of four rates of K (0, 62.5, 125.0, 250.0 kg K ha^{? 1}) and two types of K (K₂SO₄ and KCl). Cotton cultivar S-12 (Gossypium hirsutum L.) was used as a test crop. Plant mapping data showed that the total number of fruiting positions, number of intact fruit on sympodia/monopodia, and percent of bolls per position on sympodia differed greatly under different doses of K fertilizer. The percentage of fruit retention was markedly improved under increasing doses of K fertilizer as compared with the K-unfertilized treatment. The percent survival of harvestable bolls for the first five positions along sympodia at the end of the season was 30%, 25%, 18%, 13%, and 8%, respectively. Potassium fertilization stimulated cotton crop in lengthening sympodial branches and retaining more fruit on the first three positions and also at the bottom of the plant during the early reproductive phase. The fruiting pattern was 2–3 and 6–7 d vertical and horizontal fruiting interval, respectively.