Influence of Inorganic Phosphorus,VAM Fungi,and Irrigation Regimes on Crop Productivity and Phosphorus Transformations in Okra (Abelmoschus esculentus L.)–Pea (Pisum sativum L.) Cropping System in an Acid Alfisol

The present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, India, during 2009–2011 to economize inorganic phosphorus (P) and water needs of an okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through vesicular arbuscular mycorrhizal (VAM) fungi (Glomus mosseae) in a Himalayan acid Alfisol. The field experiment was replicated three times in a randomized block design comprising 14 treatments consisting of 12 treatment combinations of two VAM levels [0 and 12 kg ha^?1], three phosphorus levels [50, 75, and 100% of recommended soil-test-based nitrogen (N)–P–potassium (K)], and two irrigation regimes [40 and 80% of available water-holding capacity of field soil (AWC)], in addition to one treatment with “generalized recommended NPK dose with generalized recommended irrigations (GRD)” and one treatment based on “farmers’ practice of plant nutrition and irrigation management in the region.” This article presents crop productivity and P dynamics studies during the second crop cycle of okra–pea sequence (2010–2011) and statuses of different P fractions in the soil after the second pea crop harvest during 2010–2011. Crop productivity and P uptake data in okra–pea sequence indicated that application of VAM + 75% P dose at either of two irrigation regimes did not differ significantly than GRD treatment and VAM + 100% P dose. It suggests an economy of about 25% inorganic P dose through VAM fungi. The treatments imbedded with VAM inoculation enhanced the P uptake in okra–pea system, on an average by 21% over the GRD and non-VAM-inoculated counterparts. Further, integrated application of P, VAM, and irrigation regimes evaluated in okra–pea sequence for 2 years led to greater status of water-soluble P (21%), sodium bicarbonate (NaHCO₃)–inorganic phosphorus (Pi) (11%), sodium hydroxide (NaOH)–Pi (9%), hydrochloric acid (HCl)–extractable–P (20%) over non-VAM-inoculated counterparts and low status of organic P (NaHCO₃-P_o and NaOH-P_o), all of which appreciably contributed to available P supply to plants in the present study in an acid Alfisol. The correlation coefficient reveals that contribution of inorganic P forms is highly correlated to crop productivity and total P uptake in okra and pea crops besides soil available P in the present study. Overall, it is concluded that VAM inoculation in okra–pea cropping system significantly enhanced the P availability to plants by way of enriching the labile-P pool such as water-soluble P and P loosely bound to aluminium (Al-P) and iron (Fe-P) on adsorption complexes and by P mineralization from organic matter in an Himalayan acid Alfisol.     

Field evaluation and economics of insecticides against the major pests of okra

Abstract

Bio‐efficacy of 15 insecticides was evaluated against the pest complex of okra in the semi‐arid region of Rajasthan during July‐October, 1984. Five sprays given at intervals of 15 days throughout the crop period indicated that fenvalerate (0.02%) was most effective, followed by permethrin (0.02%), cypermethrin (0.02%), carbaryl (0.10%), monocrotophos (0.04%) and dimethoate (0.03%), against leafhoppers, aphids and fruit borer. The maximm yield of marketable fruits was obtained with fenvalerate, followed by cypermethrin, carbaryl, monocrotophos and dimethoate treatments. Highest net‐profit of Rs. 4890.00 was also recorded with fenvalerate treatment, followed by Rs. 4430.00 with carbaryl, Rs. 4148.00 with permethrin, Rs. 3977.00 with monocrotophos and Rs. 3053.00 with dimethoate treatments. A higher benfit cost ratio was found with carbaryl (1:9.78), followed by dimethoate (1:7.85), monocrotophos (1:5.18), methyl demeton (1:5.07), fenvalerate (1:3.43) and permethrin (1:2.41). These insecticides can also be used against insect pests of other vegetable crops of the season.     

Variation in Okra

Summary A study of the variation of 29 characteristics of 585 varieties or seedlings of okra revealed that 17 West African varieties could be distinguished from all others on the basis of 5 discriminating characteristics. In addition, seedlings of the 3rd outcrossing generation of a population differed from a varietal collection in several characteristics, the most important of which were more seeds per pod and more pods per plant. This is believed to be the result of mass-selection. Country groups differed significantly in characteristics but these differences are believed to be due to small sample size. No such distinguishing characteristics were evident among country groups represented by large numbers of varieties.     

Future prospects of the genetic integrity of two species of okra (Abelmoschus esculentus and A. caillei) cultivated in West Africa

Summary A study of the geographical distribution of two species of okra, Abelmoschus esculentus and A. caillei, shows that both are cultivated in almost all villages from the Gulf of Guinea to the southern limit of the Sahel. If the cultivars of both species, collected in the same village, are sown simultaneously, as often is the case, study of flowering reveals the possibility of interspecific pollination during about 7 weeks to 2 months. Interspecific hybrids can be obtained artificially, but at experimental stations and in the field very low rates of cross fertilization are observed. In addition, the sterility of the F1 hybrids makes their genetic participation in subsequent generations unlikely. In this study, we show that: 1) although grown for the same purpose, the two species are clearly managed as two separate crops by local growers; 2) the conditions which allow gene flow between both crops exist, and 3) the rate of spontaneous introgressions is low. The genetic integrity of the two species does not, therefore, seem threatened and the relative balance between them is mainly tied to the choice of the growers.     

Field efficiency of biofertilizers on the growth of okra (Abelmoschus esculentus [(L.) Moench])

An experiment was carried out at the Farm of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh from March to July, 2001 to investigate the effect of biofertilizers on morpho‐physiological characters of okra. The experiment was laid out in a randomized complete block design with four replications. There were nine treatments such as T₀ (control), T₁ (Azotobacter biofertilizer), T₂ (Azospirillum. biofertilizer), T₃ (Azotobacter + Azospirillum. biofertilizers), T₄ (Azotobacter + Cowdung 5 t ha^–1), T₅ (Azospirillum + 5 t ha^–1 cowdung), T₆ (Azotobacter + Azospirillum + 5 t ha^–1 cowdung), T₇ (5 t ha^–1 cowdung), and T₈ (60 % N). The experimental results revealed significant variations among the treatments in respect of morphological characters, e.g. plant height, number of leaves per plant, stem base diameter, tap root length, and physiological characters like root dry weight, leaf area index, and crop growth rate. Number of leaves per plant, stem base diameter, root length, root dry weight, leaf area index, and crop growth rate were larger in T₄, T₅, T₆, and T₈ than the others. In all the parameters, T₈ gave the similar result with biofertilizers in combination with cowdung treatments, and T₇ was identical with T₀ (control). These experimental results revealed that morpho‐physiological characters of okra could be modified by the application of biofertilizer + cowdung. However, biofertilizers + cowdung treatments were comparable to T₈ (60 % N) in this study. This suggests that T₄ or T₆ or T₅ were more benificial in environmentally friendly okra cultivation and may be used as an alternative of inorganic N by saving cost of production and sustaining productivity.     

鸡脚叶型陆地棉群体若干性状的研究

用连继回交转育获得的鸡脚叶、正常叶近等基因系为材料,研究结果表明,鸡脚叶光合速率和叶绿素含量均与正常叶无显著差异。鸡脚叶单叶面积极显著地小于正常叶,但单株叶面积与正常叶差异不显著。鸡脚叶群体内日光透射量增加,相对湿度降低,田间小气候明显改善,由此使烂铃减少40.7%,植株中下部位叶片和青铃上的农药附着量分别提高2.2—2.4倍和39.2%—104.3%。     

Growth and yield response of papaya to intercropping with vegetable crops in southwestern Nigeria

At Ibadan, southwestern Nigeria, papaya trees were intercropped with okra, watermelon, sweet potato, bush greens, jews' mallow and Solanum gilo Raddi. The aim of the experiment was to select crops suitable for intercropping in the alleys of papaya plants in orchards. Sweet potato and Solanum gilo Raddi caused marked reduction in the yield of papaya. Land Equivalent Ration (LER) for papaya intercopped with okra, water-melon, sweet potato, bush greens, jews' mallow and Solanum gilo Raddi were 3.86, 3.13, 2.06, 1.86, 1.60 and 1.54, respectively; indicating that all the combinations were more advantageous than the monocrop of papaya. Monetary value of the mixtures, however, indicated that the inclusion of intercrops of sweet potato or Solanum gilo Raddi, is disadvantageous.Although intercropping in papaya orchards is beneficial, it should be limited to the early vegetative and late fruiting phases of papaya when the Leaf Area Index (LAI) of papaya is low. A relay of okra followed by watermelon or bush greens followed by jews' mallow (or sweet potato grown for fodder) is considered suitable for intercropping the alleys of papaya.     

黄秋葵品种比较试验初报

选择 4个黄秋葵品种 ,进行品种比较试验。结果表明 :不同的黄秋葵品种 ,其生育期、形态特征有一定的差别 ,单位面积的产量存在着显著的差异 ,各品种的抗病性及抗虫性都比较强。综合看广东黄秋葵表现最好 ,八角黄秋葵与红秋葵次之 ,可以在本地区作为黄秋葵生产推广品种 ;而绿秋葵表现比较差 ,产量低 ,成熟晚 ,不适宜推广。     

氮磷配施对沿海滩涂黄秋葵生长发育、产量及品质的影响

通过田间小区试验的方法,研究氮磷配施对沿海滩涂黄秋葵生长发育、产量及品质的影响。结果表明:氮(N)肥、磷(P)肥对黄秋葵生长发育、产量及品质均具有显著效应,以N肥影响最大;当氮肥为300kg·hm-2、磷肥为160kg·hm-2时,黄秋葵产量最高,且荚果单果重、果皮光合色素含量、游离氨基酸、可溶性蛋白含量和荚果黏度达到最高值,即黄秋葵产量与整体品质较高,表明在本试验条件下,该施肥量为江苏沿海滩涂黄秋葵大田种植最佳施肥模式。     

黄秋葵果胶涂膜液在冷鲜肉、冷鲜鱼保鲜中的应用研究

以黄秋葵嫩果为原料经水提获得果胶,并配成不同浓度的水溶液对冷鲜肉片和冷鲜鱼片进行涂膜保鲜。结果显示：黄秋葵果胶涂膜液对冷鲜肉片和冷鲜鱼片均具有保鲜作用。其中,稀释液1对冷鲜肉片保鲜效果最好,可明显延长贮存期2~3 d;原液对冷鲜鱼片保鲜效果最好,可明显延长贮存期2~3 d。此为可食性涂膜保鲜液的开发和黄秋葵的深加工提供了理论基础。