Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill −1 on the productivity of rice in Dera Ismail Khan district of North West Frontier Province (NWFP), Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 11th of July while sub-plots contained 1, 2, 3 or 4 seedlings hill . It explains that the use of more seedlings hill −1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of 1 seedling hill −1 is most appropriate for timely sowing otherwise 4 seedlings hill -1 should be used to compensate for the yield gap in late transplanted rice.

-The genus Euphorbia comprises about 2000 species ranging from annuals to trees, including C 3 , C 4 , and CAM species. Euphorbia species widely studied in agriculture includes E. antiquorum, E. carollata, E. dentata, E. dracunculoides, E. esula, E. geniculata, E. granulata, E. helioscopia, E. heterophylla, E. hierosolymitana, E. hirta, E. maculata, E. microphylla, E. nerifolia, E. piluifera, E. pulcherrima, E. royleana, E. supine, and E. thiamifolia. These species have been reported mainly in field crops/vegetables, orchards, pastures, and rangelands. Euphorbia plants may present allelopathic effect over desirable cereals, pulses, oilseeds, vegetables, forage plants, and nitrifying bacteria, posing a serious threat to livestock production on open range lands through the release of allelochemicals from roots, stems, leaves, and inflorescence in the rhizosphere. Leaves are reported to be more toxic than other plant parts. Competition of Euphorbia spp. against crop plants is the most important crop yieldlimiting factor. The critical period for Euphorbia competition with crops is reported to take place between 17 to 70 days after emergence for most crops, depending on root development during the initial crop growth stage, crop height, tillering or branching capacity, whether weeds emerge at the same time as the crop or later after crop emergence; how quickly crop canopy develops and also on Euphorbia species. A yield reduction of 4-85% has been reported in field crops with different Euphorbia species and distinct occurrence densities. Euphorbia species decrease herbage production by 10 to 100% in pasture and rangelands, with many acting as natural insecticide, fungicide, nematidicide, immunopotentiator, or immunosuppressor.Keywords: competition, allelopathy, crops, pastures, livestock, plant protection.RESUMO -O gênero Euphorbia compreende cerca de 2.000 espécies, que variam de plantas anuais a árvores, incluindo C3, C4 e espécies CAM. As espécies de Euphorbia amplamente estudadas na agricultura incluem E. antiquorum, E. carollata, E. dentata, E. dracunculoides, E. esula, E. geniculata, E. granulata, E. helioscopia, E. heterophylla, E. hierosolymitana, E. hirta, E. maculata, E. microphylla, E. nerifolia, E. piluifera, E. pulcherrima, E. royleana, E. supina e E. thiamifolia. Essas espécies têm sido relatadas principalmente em culturas de campo, legumes/pomares, pastagens e pastagens. Plantas de Euphorbia podem apresentar efeito alelopático sobre cereais, leguminosas desejáveis , oleaginosas, vegetais, plantas forrageiras e bactérias nitrificantes, o que representa uma séria ameaça para a produção de gado em terras abertas, através da liberação de aleloquímicos de raízes, caules, folhas e inflorescências na rizosfera. As folhas são mais tóxicas do que outras partes da planta. A competição de Euphorbia spp. com plantas de cultivo é o mais importante de todos os fatores que limitam a produtividade das culturas. O período crítico da competição de Euphorbia com as colheitas é relatado como sendo entre 17 e 70 di...

Phytotoxic effect occurs when plants release chemicals that inhibit neighoubouring plants. Phytotoxic effects of aqueous extracts of different parts of Euphorbia dracunculoides L. (green spurge) at two concentrations, and its infested soil were investigated on germination and seedling growth of chickpea (Cicer arietinum L.). The fruit extract at 1:20 (w/v) concentration caused maximum reduction (12%) in germination of chickpea seeds while leaf extract at 1:10 (w/v) concentration resulted in maximum mean germination time value and minimum germination index of chickpea seeds. All the traits of chickpea seedling growth including emergence were adversely affected by the aqueous extracts at both concentrations. Further, the inhibition of chickpea seedling growth was more pronounced with 1:10 (w/v) concentration whereas the lower concentration (1:20 w/v) showed stimulatory effect on shoot length, seedling vigor index and chlorophyll contents of chickpea seedlings. The leaf extract at 1:10 (w/v) concentration proved most harmful to seedling growth and chlorophyll contents (76% reduction) of chickpea. Soil beneath the E. dracunculoides plants significantly reduced emergence (23%), seedling vigor index (55%) and chlorophyll content (19%) of chickpea but a significant increase in N (6%), P (16%) and K (4%) contents of chickpea seedlings was recorded. Thus it can be concluded that E. dracunculoides contains compounds in its tissues which may cause phytotoxic effects on chickpea under field conditions. Additional key words: Cicer arietinum; emergence; germination; green spurge; phytotoxicity; seedling growth. ResumenEfectos fitotóxicos de Euphorbia dracunculoides, una mala hierba del sistema de cultivo garbanzo-garbanzo de secanoSe produce un efecto fitotóxico cuando las plantas liberan sustancias químicas que producen inhibiciones en las plantas próximas. Utilizando extractos acuosos a dos diferentes concentraciones de distintas partes de Euphorbia dracunculoides L., así como del suelo infestado, se investigaron sus efectos fitotóxicos sobre la germinación y crecimiento de plántulas de garbanzo (Cicer arietinum L.). Extractos del fruto 1:20 (p/v) provocaron la máxima reducción (12%) en la germinación de las semillas de garbanzo, mientras que extractos de hoja 1:10 dieron el máximo valor del tiempo medio de germinación y el mínimo en el índice de germinación. Todos los caracteres de crecimiento de las plántulas de garbanzo, incluyendo la emergencia, fueron perjudicados por los extractos acuosos a ambas concentraciones. Además, la concentración 1:10 inhibió el crecimiento de las plántulas de garbanzo de forma más pronunciada, mientras que la 1:20 mostró un efecto estimulante sobre la longitud de brotes y el índice de vigor y contenido de clorofila de las plántulas de garbanzo. El extracto de hoja 1:10 resultó más perjudicial para el crecimiento de plántulas y el contenido de clorofila (76% de reducción). Suelo extraído debajo de las plantas de E. dracunculoides redujo significativamente la emergencia (23%), el índice...

To study the effect of high temperature, rice seedlings 20, 30, 40 and 50 d were kept at 5, 10, 15 and 20 cm water depth in a water pool. Meteorological findings indicated that water temperature varied up to 10 cm but became stable below this depth. Deep water inflicted higher tiller mortality, minimal increase in dry weight of aerial parts and leaf area, decrease in root length, and decrease in root dry weight especially at 20 cm water depth and produced an unbalanced T/R ratio (top versus root dry weight). However, deep water tended to increase plant length. These parameters, however, excel in shallow water. Older seedlings, with the exception of root dry weight, could not perform well compared to young seedlings in all physiological and morphological aspects. The study revealed that seedlings, particularly young ones, stand well in shallow water and can cope with high temperature.

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The effect of irrigation frequencies i.e. 0, 2, 4, 6 and 8 was studied at the Faculty of Agriculture, Gomal University, Dera Ismail Khan, during the year 1995. The parameters like plant height, head diameter, number of grains per head, 1000-grain weight and grain yield per hectare were significantly affected by irrigation levels and six irrigations were found optimum for obtaining good yield of sunflower. On the basis of research findings, six irrigation are recommended for sunflower crop to obtain maximum seed yield under irrigated conditions.

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