Effect Of Phosphorus Application Research Articles

Effect of Phosphorus Application and Varieties on Grain Yield and Yield Components of Common Bean (Phaseolus vulgaris L.)

Effect of Phosphorus Application and Varieties on Grain Yield and Yield Components of Common Bean (Phaseolus vulgaris L.)

Effects of phosphorus application on photosynthetic carbon and nitrogen metabolism, water use efficiency and growth of dwarf bamboo (Fargesia rufa) subjected to water deficit

Dwarf bamboo (Fargesia rufa Yi), one of the staple foods for the endangered giant pandas, is highly susceptible to water deficit due to its shallow roots. In the face of climate change, maintenance and improvement in its productivity is very necessary for the management of the giant pandas' habitats. However, the regulatory mechanisms underlying plant responses to water deficit are poorly known. To investigate the effects of P application on photosynthetic C and N metabolism, water use efficiency (WUE) and growth of dwarf bamboo under water deficit, a completely randomized design with two factors of two watering (well-watered and water-stressed) and two P regimes (with and without P fertilization) was arranged. P application hardly changed growth, net CO2 assimilation rate (Pn) and WUE in well-watered plants but significantly increased relative growth rate (RGR) and Pn in water-stressed plants. The effect of P application on RGR under water stress was mostly associated with physiological adjustments rather than with differences in biomass allocation. P application maintained the balance of C metabolism in well-watered plants, but altered the proportion of nitrogenous compounds in N metabolism. By contrast, P application remarkably increased sucrose-metabolizing enzymes activities with an obvious decrease in sucrose content in water-stressed plants, suggesting an accelerated sucrose metabolism. Activation of nitrogen-metabolizing enzymes in water-stressed plants was attenuated after P application, thus slowing nitrate reduction and ammonium assimilation. P application hardly enlarged the phenotypic plasticity of dwarf bamboo in response to water in the short term. Generally, these examined traits of dwarf bamboo displayed weak or negligible responses to water-P interaction. In conclusion, P application could accelerate Pn and sucrose metabolism and slow N metabolism in water-stressed dwarf bamboo, and as a result improved RGR and alleviated damage from soil water deficit.

Foliar Zinc, Nitrogen, and Phosphorus Application Effects on Micronutrient Concentrations in Winter Wheat

Although foliar application of Zn is highly efficient in improving Zn concentration in wheat (Triticum aestivum L.) grain, it may be beneficial to better understand its effectiveness when combined with foliar applications of N or P. A 2‐yr field experiment was conducted to evaluate the efficacy of concurrent ZnSO4, and commonly used N and P applications on grain Zn, and other nutritional quality indices in wheat. On average, grain Zn concentration increased by 84, 83, and 55% following foliar application of Zn, Zn+N, and Zn+P, respectively. The Zn concentration following foliar application was much greater in the leaves than in the glume or stem. The reduction in the Zn content and the distribution of Zn in the grain and leaves was similar following foliar‐applied Zn and foliar‐applied Zn+P. This suggests that absorption of Zn in the vegetative tissues (e.g., leaf) was reduced with the addition of P in the foliar spray, but translocation of Zn from the leaf to grain was not inhibited by P. Foliar Zn+N application significantly increased grain protein, Fe, and Ca concentrations, and foliar Zn+P application significantly increased Fe and Ca concentrations. Foliar application of Zn, Zn+N, and Zn+P significantly decreased grain phytic acid (PA)/Zn, PA/Fe, and PA/Ca molar ratios. The results of this study suggest that the inclusion of Zn in commonly used foliar applications of N or P may be effective for increasing grain Zn concentration in wheat.

Effect of Phosphorus Application on Durum Wheat in Alkaline Sandy Soil in Arid Condition of Southern Algeria

Effect of Phosphorus Application on Durum Wheat in Alkaline Sandy Soil in Arid Condition of Southern Algeria

Effects of Phosphorus Application in Different Soil Layers on Root Growth, Yield, and Water-Use Efficiency of Winter Wheat Grown Under Semi-Arid Conditions

Deep phosphorus application can be a usefull measure to improve crops’ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus (P) application at different soil layers on root growth, grain yield, and water-use efficiency (WUE) of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars: one drought-sensitive (Xiaoyan 22, XY22) and one drought-tolerant (Changhan 58, CH58). The four P treatments were no P (control, CK), surface P (SP), deep P (DP), and deep-band P application (DBP). CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments (DP and DBP) than under SP, clearly showing that deep P placement had beneficial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight (RW) and root length (RL) in deep soil layer (30-100 cm) were closely positively correlated with grain yield and WUE of CH58 (but not XY22), highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars (r=0.94, P<0.001). In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.

The effect of phosphorus application and balance on concentrations in streams from agricultural dominated catchments in Norway

Elevated phosphorus (P) use is a worldwide problem for the sustainability of agricultural production with consequences for both food production and water quality. The objective of this paper was to investigate the effect of P application and P balance on stream P concentrations in different production systems of Norwegian agriculture. The average application of P in the studied catchments ranged from 21 to 53 kg P ha−1 yr−1, including the P application in both mineral fertiliser and manure for the monitoring periods (16–20 years). The highest P application was found in a catchment with high livestock density, and potato and vegetable production. This catchment also showed the highest P balance (applied P minus P removed with yields) of 26 kg P ha−1 yr−1 on average, and also a very high soil P status (P-AL). The P balance for all other catchments ranged from 3 to 13 kg P ha−1 yr−1. For all catchments, the average application of mineral P fertiliser decreased during the monitoring period, especially during the last 2–3 years. However, total P application increased in three catchments due to increased livestock density and manure P application. Average concentrations of total P in the streams varied from 65 to 392 µg L−1. The highest concentration was measured in the stream from the catchment with highest P balance and soil P status. The concentrations of dissolved reactive P varied from 27 to 63 µg L−1 with the highest concentration measured from an area with intensive livestock production. Reducing P application and soil P status to the minimum level for crop growth is important for the environmental quality of surface waters.

Effect of phosphorus application on soil available phosphorus and maize phosphorus uptake and yield

为了给玉米磷高效利用提供理论依据, 在低磷土壤(Olsen-P 4.9 mg·kg^-1)上, 通过田间试验, 研究了施磷0(T₀)、50 kg(P₂O₅)·hm^-2(T₁)、100 kg(P₂O₅)·hm^-2(T₂)、200 kg(P₂O₅)·hm^-2(T₃)、1 000 kg(P₂O₅)·hm^-2(T₄)对两个玉米品种"鲁单9002" (LD9002)、"先玉335"(XY335)的产量、磷素吸收利用及根际磷动态变化的影响。结果表明: 两玉米品种根际土、非根际土速效磷含量在不同生育时期都表现为T1<T2<T3<T4; 播种后61 d时施磷200 kg(P₂O₅)·hm^-2的T₃处理非根际土转化为根际土土壤磷的量最大, 同时玉米生物量、产量、磷转移量也达到最高, 而施磷1 000 kg(P₂O₅)·hm^-2处理玉米生物量、产量与中磷水平相比没有显著增加, 但植株吸磷量较高。XY335的花后磷转移量小于LD9002。相关分析表明, LD9002根际土、非根际土速效磷含量与茎、叶吸磷量之间显著相关, 以播种后79 d与茎、叶磷浓度、吸磷量、生物量、产量之间的相关系数最高; 而XY335根际土、非根际土速效磷含量与茎、叶磷浓度之间显著相关, 在播种后47 d期间与茎、叶磷浓度、吸磷量、生物量、产量之间的相关性最好。因此, 在低磷土壤上, LD9002和XY335分别在播种后79 d和47 d时是植株对磷的敏感期, 可以通过测试根际土、非根际土速效磷含量来反映土壤的供磷状况; LD9002在79 d时最大吸磷量需要的根际土、非根际土速效磷含量分别为54.95 mg·kg^-1、32.99 mg·kg^-1, XY335品种在47 d时最大吸磷量需要的根际土、非根际土速效磷含量分别为51.24 mg·kg^-1、35.35 mg·kg^-1; 施磷量1 000 kg(P₂O₅)·hm^-2处理两品种玉米产量、生物量、磷积累量与施磷量100~200 kg(P₂O₅)·hm^-2处理没有显著差异。

INTERACTIVE EFFECT OF SULFUR AND PHOSPHORUS ON NODULATION, NITROGEN FIXATION, AND NUTRIENT UPTAKE BY CHICKPEA GROWN ON CALCAREOUS SOILS IN PAKISTAN

Field experiments were conducted at two different locations under rainfed conditions of Punjab, Pakistan to assess nodulation, nitrogen fixation and nutrient uptake by chickpea (Cicer arietinum L.) in response to application of three rates [0, 40, and 80 kg phosphorus pentoxide (P2O5 ha−1)] of phosphorus and three rates (0, 15 and 30 kg S ha−1) of sulfur in different combinations. Effect of phosphorus application was nonsignificant while that of sulfur was significant on percent nitrogen derived from atmosphere. Both phosphorus and sulfur application resulted in increase in nitrogen fixation up to 38% and 33% over control, respectively. Nutrient uptake [nitrogen (N), phosphorus (P), and sulfur (S)] increased significantly with the application of phosphorus and sulfur and correlated positively with nitrogen fixation. There is direct involvement of sulfur in the process of nitrogen fixation whereas effect of phosphorus on nitrogen fixation is indirect mainly through enhanced growth and dry matter production.

Effects of phosphorus application on root respiration and heterotrophic microbial respiration in Acacia mangium plantation soil

We investigated the effects of phosphorus (P) application on root respiration (RR) and heterotrophic microbial respiration (MR) in an Acacia mangium plantation using a trenching method. Mean RR was 0.46g Cm-2 day-1 in a non-P-applied plot, which accounted for 16% of total soil respiration, exhibiting a lower RR value and proportion of total soil respiration compared with previous studies. Mean MR was 2.41g Cm-2 day-1, accounting for 84% of the whole soil respiration. P application significantly (P <0.01) increased the mean RR from 0.46 to 0.88g Cm-2 day-1. Applied P was readily absorbed by acacia trees, which was inferred from the lower available P and total P in non-trenched plots compared to the trenched plots, and it is likely that the absorbed P stimulated root activities and RR. P application also significantly (P <0.001) increased the mean MR from 2.41 to 2.89g Cm-2 day-1, probably because P application relieved the P shortage and stimulated microbial organic matter decomposition. Our study suggests that when assessing the effects of P fertilization on C cycling in forest plantation, we should take account of the effects on organic matter decomposition and soil respiration, not only the effects on C sequestration by trees.

Effects of phosphorus application on CH4 fluxes in an Acacia mangium plantation with and without root exclusion

Effects of phosphorus application on CH4 fluxes in an Acacia mangium plantation with and without root exclusion

Effect of phosphorus application and strip-intercropping on yield and some wheat- grain components in a wheat/maize/potato intercropping system

Intercropping of bread wheat (Triticum aestivum L.), maize (Zea mays L.) and potato (Solanum tuberosum)has been practiced in North-West China in the last several decades; however, the effects of this intercropping and phosphorus addition on crop yield and some wheat-grain components have not been adequately investigated. A 2-year field experiment was conducted from 2002 to 2003 in irrigated areas in North-West of China to investigate how phosphorus fertilizer application and intercropping of wheat/maize/potato impact on the crop yield and wheat-grain components such as protein content, wet gluten and sodium dodecyl sulphate (SDS) sedimentation. The results indicated that bread wheat and maize achieved higher yields in the intercropping system than in the monoculture system over the 2 years, and the wheat-grain had higher protein content, wet gluten and sodium dodecyl sulphate (SDS) sedimentation in the intercropping system than in the monoculture system. Better utilization of resources through border row effect and preventing competition between species over growing period have been indicated as the major factors contributing to the increased crop yield and wheat-grain components. Phosphorus application significantly increased crop yields and improved wheat-grain components; however, the optimal application rate for achieving highest protein content was at 150 kg ha-1. The practical implication of the present study was that to obtain good yield and better wheat-grain components, a combination of intercropping and application of phosphorus fertilizer at a rate of approximately 150 kg ha-1 was found as one of the most practical options. Key words: Border-row effect, intercropping, phosphorus, wheat-grain components, wheat/maize/potato, yield.

Effect of phosphorus application on growth of bitter Chinese lettuce and soil phosphorus leaching

利用网室土柱模拟试验, 研究了不同磷用量[0、0.05 g·kg^-1(土)、0.10 g·kg^-1(土)、0.20 g·kg^-1(土)]对苦麦菜产量、磷素吸收和利用及土壤磷淋失的影响。结果表明, 施磷显著增加苦麦菜产量、促进植株对磷的吸收。苦麦菜产量在低磷水平[0.05 g·kg^-1(土)]时最高, 为每个土柱186.29 g。随磷用量增加, 苦麦菜产量和磷肥利用率明显降低, 植株吸磷量无明显变化。施磷显著增加土壤磷淋失量, 且随磷用量增加, 不同形态磷淋失量均显著增加。同一磷处理颗粒磷淋失量高于溶解态磷。不同磷用量条件下土壤各形态磷的淋失率均低于0.1%。低量施磷条件下溶解态磷在施磷后第10 d 出现第1 次淋失高峰; 中量和高量施磷条件下溶解态磷在施磷后第10 d 和第40 d 分别出现2 次淋失高峰。土壤总磷和颗粒磷淋失高峰期在施磷后第40~50 d 出现。施肥后第60 d, 土壤总磷、溶解态磷和颗粒磷淋失浓度均明显降低。综合考虑苦麦菜产量、磷素吸收和利用及土壤磷淋失量等因素, 苦麦菜以0.05 g·kg^-1(土)的施磷量为佳。

Effects of Phosphorus Application on Phosphorus Adsorption and Desorption of Cotton Field Soil at Different Growing Stages

In this paper,the effects of phosphorus application on phosphorus adsorption and desorption of soils in two different cotton fields are studied.The results show that there is an extremely significance between the phosphorus isothermal adsorption curves of loam soil at various growth stages of cotton and the fittings with the Langmuir equation,Temkin equation and Freundlich equation,especially with the Freundlich equation,and the correlation coefficients are higher than 0.96.Phosphorus adsorption saturation(PAS),net phosphorus concentration at zero adsorption(PCA0),phosphorus absorption,phosphorus desorption and phosphorus desorption rate increased with increasing the amount of applied phosphate fertilizer,while the standard phosphorus requirement(SPR) decreased.The results estimated with the Freundlich equation show that the SPRs(in accordance with the conversion of phosphate fertilizer containing 46% P2O5) at the seedling stage,the flowering-bolling stage and the boll-opening stage of cotton in loam cotton field were 143.7,137.4 and 160.2 kg/hm2,and the SPRs at the seedling stage,the flowering-bolling stage and the boll-opening stage in sandy loam cotton field were 106.6,251.1 and 173.0 kg/hm2,respectively.

Effect of Phosphorus Application on Clusterbean under Different Intensities of Water Stress

ABSTRACT Response of clusterbean [Cyamopsis tetragonoloba (L.) Taub.] to phosphorus (P) application (0 and 40 kg ha−1) under different intensities of water stress at the critical pre-flowering stage was studied in a pot trial by withholding irrigation for 0, 3, 6, and 9 days. Increasing stress intensity progressively decreased plant water potential (Ψplant), relative water content, levels of different leaf metabolites, photosynthetic rate, and nitrate reductase activity under both phosphorus (P) treatments. However, P-fertilized plants displayed higher photosynthetic efficiency, leaf metabolism, and enzyme activity than unfertilized plants, though decrease in plant water status was more in P-fertilized plants. Recovery upon rewatering was also more in P-fertilized than unfertilized plants with respect to all the parameters studied. Consequently, P application significantly enhanced dry matter and seed yields at all stress intensities. The results indicate the possibility of alleviation of water stress effects by P nutrition in clusterbean, at least up to moderate stress level.

Effect of phosphorus application and soybean cultivar on grain and dry matter yield of subsequent maize in the tropical savannas of north-eastern Nigeria

Soybean can contribute to soil N, which may partly be used to improve maize production in northeast Nigeria. However, the efficiency of soybean to fix N can be limited by soil P deficiency. This study evaluated the effect of P application and soybean cultivars on dry matter and grain yield of subsequent maize for two years (2005 - 2006) at Miringa and Azir. Experimental design was a split-plot with three replications. The main plots contained P levels of 0, 20 and 40 kg P/ha and subplots had four soybean cultivars. Maize was planted in the harvested soybean plots. Application of P to soybean at 20 and 40 kg/ha significantly increased dry matter and grain yield of succeeding maize. Differences in grain yield were significant between all P rates in Miringa (2005) and Azir (2006) but only between 0 and 40 kg P/ha in Azir (2005) and Miringa (2006). The grain yields of maize following late-maturing soybean cultivars were significantly higher than those following the early maturing cultivars in 2005. The maize yield increases could however, not be explained by total soil N, available P, and N and P uptake. Other rotation effects beyond N supply by the preceding soybean may be responsible for the yield increases of maize.

Effect of Phosphorus Application and Time of Harvest on Yield and Quality of Moth bean [Vigna aconitifolia (Jecq.) Marechal

Effect of Phosphorus Application and Time of Harvest on Yield and Quality of Moth bean [Vigna aconitifolia (Jecq.) Marechal

Crescimento , produção de matéria seca e acúmulo de N, P, K, Ca, Mg e S na parte aérea de mudas de andiroba (Carapa guianensis Aubl.) cultivadas em solo de várzea, em função de diferentes doses de fósforo

Com o objetivo de avaliar o efeito de diferentes doses de fósforo no crescimento e produção de matéria seca e acúmulo de N, P, K, Ca, Mg e S na parte aérea de mudas de andiroba, cultivadas em solo de várzea, foi conduzido um experimento em casa de vegetação, no Departamento de Ciências do Solo (DCS) da Universidade Federal de Lavras (UFLA). O delineamento utilizado foi em blocos casualizados com cinco repetições e quatro doses de fósforo (0, 150, 300 e 450 mg dm-3 de P). Foram avaliados diâmetro do caule (mm), altura de plantas (cm), matéria seca de raiz, caule, folha e total (g planta-1). A partir dos teores dos elementos, determinou-se o acúmulo dos nutrientes com base na matéria seca. A máxima resposta física da planta de andiroba à adubação fosfatada foi obtida na faixa de 239 a 265 mg dm-3 de P. O máximo acúmulo de N, P, K, Ca, Mg e S foi atingido com as doses de 254; 287,5; 244,5; 254; 241; e 275 mg dm-3 de P, respectivamente. Os elementos em estudo que mais acumularam na parte aérea das mudas de andiroba seguem a seguinte ordem decrescente: N &gt; Ca &gt; K &gt; Mg &gt; S &gt; P.

신개간 및 기경작 초지토양간 목초의 생산성과 무기양분 함량 비교 III. 인산 사용에 따른 토양특성, 목초의 초기 생육, 수량 및 무기양분 함량 변화

동일한 토양종류(토양명: 송정통)에서 서로 인접한 신개간 및 기변작 초지토괴간 비파저 특성의 차이와 시비처리별 orchardgrass 목초의 초기생육상, 수양과 부기양분 함량의 차이를 비교 . 검토하고자 기초시험으로 pot 시험을 수행하였다. 금지토양의 비담도 개량과 크게 연관된 자비(I보), 석회(II보) 및 인산(III보)의 시용 효과를 단계별로 검토하였다. 본 III보에서는 질소, 가리 및 고토를 동일하게 기본시비를 한 조건에서 1) 인산 무비구(<TEX>$P_{0}$</TEX>; control), 2) 인산 보비구(<TEX>$P_1$</TEX>; 1.25g), 3) 인산 배비구(<TEX>$P_2$</TEX>; 2,50g), 4) 인산 다비구(<TEX>$P_3$</TEX>; 3.75g <TEX>$P_2$</TEX><TEX>$O_{5}$</TEX> pot)를 처리 내용으로 한 두 토양간 인산의 비효를 비교.검토하였다. 1. 시험전 신개간 및 기경작 초지토양간 토양의 화학성(비담도)에 큰 차이를 보였다. 초지토양 비담도 등금기준(불량-보통-양호)에 기준 한 각 화학성을 대비하여 보면 일반적으로 신개간 토양은 불량~보통, 기경작 초지토괴은 보통~양호 수준을 보였다. 2. 기경작 토양보다는 신개간 토양에서 인산시비량 증가에 따른 뮤효인산의 함량 증가가 뚜렷하였고, 이 특성은 기비와 병행 시비를 한경우 더 긍정적이였고, 석회와 병행 시비를 한경우는 오히려 부정적인 경향을 보였다. 반면에 기경작 토양에서논 신개간 토양에 비해서 인산 시비량 증가에 따른 유효인산 함량 증가폭이 경미하였고, 석광의 부정적 효과는 더 경감되었다. 3. 신개간 토양에서 연초의 초기생육상과 수양성은 기경작 토양의 경우보다 상대적으로 더 불량하였고, 특히 인산 무비구(<TEX>$P_{0}$</TEX> )에서는 목차의 정착과 수양성이 매우 불량하였다. 이는 인산 시비로 개선되었으나 시비된 수준간 차이는 경미하였다. 신개간 토양에서 철비와 병행 시비를 한 경우 이들 특성이 더 양호하였으며, 인산 무비구(P<TEX>$_{0}$</TEX>)의 불량한 초기생육상과 수양성은 크게 개선되었다. 반면에 기경작 토양에서는 인산 무비구(<TEX>$P_{0}$</TEX> /)에서도 이들 특성들이 양호하였으며 인산 시비수준간 차이는 경미하였다. 4. 기경작 토양은 신개간 토양보다 목초 중 무기양분 Ca, Mg 및 P 함량이 상대적으로 양호하였다. 그러나 K 함량은 두 토양간 비슷한 함량을 보였다. 획비와 병행 시용 한 경우 신개간 토양에서만 목초 중 Mg과 P 함량이 다소 높아지는 경향을 보였다.다. This pot experiment was conducted to find out the forage productivity and mineral contents in an orchardgrass sward affected by the compost, lime, and phosphorus applications on the newly reclaimed and arable pasture soils. This 3rd part was concerned with the effect of phosphorus application(<TEX>$P_{0}$</TEX> : control, <TEX>$P_1$</TEX>=1.25ｇ, <TEX>$P_2$</TEX>=2.50g, <TEX>$P_3$</TEX>=3.75g <TEX>$P_2$</TEX><TEX>$O_{5}$</TEX> pot). The results obtained are summarized as fellows; There were considerable differences between the newly reclaimed and arable pasture soils in the soil chemical characteristics as follows in general; poor~common in the newly reclaimed soil and common~good in the arable pasture soil in terms of soil fertility standard. Comparing with the arable pasture soil, the contents of available<TEX>$ P_2$</TEX><TEX>$O_{5}$</TEX> / in the newly reclaimed soil at end of experiment were considerably increased by the <TEX>$P_2$</TEX><TEX>$O_{5}$</TEX> applications, These effects in the newly reclaimed soil were positively influenced by the additional application of compost, but were adversely influenced by the additional application of lime. The seedling vigour and yield of orchardgrass were far better in the arable pasture soil than in the newly reclaimed soil. At the <TEX>$P_{0}$</TEX> treatment, those were very poor in 也e newly reclaimed soil, but were good in the arable pasture soil. Comparing with <TEX>$P_1$</TEX> treatment, the above effects of heavy <TEX>$P_2$</TEX><TEX>$O_{5}$</TEX> / applications(<TEX>$P_2$</TEX>and <TEX>$P_3$</TEX>) were not recognized. On the newly reclaimed soil, the above effects were markedly enhanced by the applications of <TEX>$P_2$</TEX><TEX>$O_{5}$</TEX> with compost. The Ca, Mg, and P contents of orchardgrass were relatively higher on the arable pasture soil than on the newly reclaimed soil, whereas ere were no differences in the K contents.

Effect of phosphorus on drought mitigation and productivity of rainfed upland rice (Oryza sativa)

The effect of phosphorus application at varying rates, viz. 0, 12, 24, 48 and 96 kg/ha, was studied on drought mitigation and productivity of two upland rice (Oryza sativa L.) varieties ('Vandana' and 'Annada') during 1999, 2000 and 2001 under rainfed upland condition at Hazaribag in Jharkhand. Phosphorus was applied basal through single superphosphate along with common doses of N, K, Zn and Mg. The effects of P rates, and interac- tion effects between P rates and varieties were significant in the drought year only (2000). Reduction in grain yield due to drought in no-P plots was 27.4% in 'Vandana' and 58.4% in 'Annada' in comparison with normal rainfall year (1 999). The grain yield of 'Annada' and 'Vandana' decreased by 11.7 and 25.4 at 24 kg Plha, and by 2.5 and 5.2 at 48 kg P/ha respectively. Maximum P-use efficiency was achieved at 24 kg P/ha in both the variet- ies. Concentration of P in grain and straw was also reduced due to drought in 2000 at low P application com- pared with that in 1999. Differences in agronomic P-use efficiency were apparent due to varieties. Agronomic P- use efficiency was 38.1 kg graintkg P in 'Annada' compared with 15.5 kg graintkg applied P in 'Vandana'. How- ever, differences due to varieties in relative effect of drought stress (RDS) and available soil P were marginal. It was concluded that the application of P @ 24 kglha helped in reducing the effect of drought as well as in in- creasing the rice productivity and P-use efficiency of rainfed upland rice.

Effect of phosphorus application in legume cover crop rotation on subsequent maize in the savanna zone of West Africa

The benefit of planted fallow with legume cover crops may be limited on P deficient soil. A trial was conducted at two P deficient sites in northern Nigeria to test the hypothesis that application of P to legume cover crop fallow can substitute for N application to subsequent maize. Mainplots consisted of leguminous fallows followed by unfertilized maize, or native (mostly grass) fallows followed by maize with 0 or 40 kg N ha−1 (Kaduna) and 0, 30 or 60 kg N ha−1 (Bauchi). Three rates of P (0, 9, and 18 kg ha−1) were applied to fallow sub-plots as single superphosphate. In the first year, dry matter accumulation of lablab (Lablab purpureus) responded to P application, while mucuna (Mucuna cochinchinensis) dry matter did not. Lablab mulch dry matter during the dry season was significantly increased by previous season P application while mucuna was not. Previous fallow vegetation was a significant factor for maize growth in the second year but the interaction with P applied to the fallow was not significant at P < 0.05. Substantial and similar yield increases were achieved with application of N fertilizer to maize and from application of 9 kg P ha−1 to previous lablab. Depending on local economic circumstances, a good use of expensive inorganic fertilizer might be to apply P sources to cover crop legumes to profit from additional N benefits as well as residual effects of applied P.