Yield Of Pigeonpea Research Articles

RESPONSE OF PIGEONPEA TO PHOSPHORUS AND SULPHUR NUTRITION

Field experiments were conducted over a period of two years (1989, 1990-91) at the Millet Breeding Station, Tamil Nadu Agricultural University, Coimbatore. The results showed that combined application of phosphorus and sulphur had resulted in the increased yield or pigconpca. Appliciation of phosphorus at 20 kg/ha and sulphur at 20 kg/ha was found to be the optimum for getting the increased yield of pigeonpea.

Studies on biological control of Pigeonpea Pod Borers in India

Results of two field experiments, one on SA 1 pigeonpea in rainfed and the other on Co.5 pigeonpea in irrigated conditions revealed thatBacillus thuringiensis var.kurstaki (B.t.k.) (Delfin), its combinations with nuclear polyhedrosis virus ofHeliothis armigera andChrysoperla carnea were as effective as endosulfan in reducing the pod borers,Heliothis armigera andExelastis atomosa. However,B.t.k. 1.25 kg+endosulfan 175 g/ha orB.t.k. 2.5 kg+HaNPV, 250 LE/ha gave better control of damage to flowers and pods thanB.t.k. applied alone on SA 1 pigeonpea. The yield differences between these treatments were not significant. A combination of HaNPV 250 LE/ha+endosulfan 175 g/ha was superior toB.t.k. Similar trend was seen on Co.5 pigeonpea. Release ofC. carnea second instar larvae 1 lakh/ha was not effective in increasing the yield of pigeonpea.

Limitations to seed yield in short-duration pigeonpea under water stress

Yield components were determined for two short-duration pigeonpea [Cajanus cajan (L.) Millsp.] cultivars, ICPL 87 and ICPL 151, in response to terminal drought stress with three partial flower/pod removal or four foliar fertilization treatments applied from the time of full flowering. Flower/pod removal treatments comprised a control with no flower/pod removal, lower-plant flower and pod removal at full flowering and 18 days later (EL), allowing pods to develop only on the top-3 nodes of the main stem, and flower/pod removal 18 days after full flowering only (L). The EL and L treatments were applied to ICPL 87 and only the EL treatment to ICPL 151. Seed yield of the top-3 nodes was increased by the EL treatment for both cultivars under rainfed and irrigated conditions, but was not significantly affected by the L treatment. With flower/pod removal, increased yields of the top-3 nodes were due to increases in the pod density and/or the seed size, with little change in the number of seeds pod−1. Foliar fertilization of cultivar ICPL 87 with solutions containing N, P, K and S in similar proportions to those found in developing seeds at 20 and 40 kg N ha−1, had no significant effects on yield or yield components under either soil moisture condition. Factors within the plant during early reproductive growth appear to limit seed yield under both soil moisture conditions, and reproductive sink capacity and nutrient (N, P, K and S) supply, apparently, are not limiting. Such information on plant factors limiting yield under water stress conditions allows for a better understanding of drought resistance mechanism(s) for short-duration pigeonpea.

Effect of Heterodera cajani on biomass and grain yield of pigeon pea on vertisol in pot and field experiments

Glasshouse and field trials were conducted to determine the effects of the cyst nematode, Heterodera cajani on biomass and grain yield of pigeon pea, Cajanus cajan. Shoot length, fresh and dry shoot masses, leaf area and pod yields of pigeon pea were significantly reduced by H. cajani. In glasshouse pot experiments, an initial density of 1.0 juveniles per cm3 soil caused 14 to 24% reduction in plant height, root and shoot mass and leaf area. Application of carbofuran 3G (1·5, 3·0 and 6·0 kg a.i./ha) in H. autoclaved soil in pots did not improve growth of pigeon pea; however, its application (6 kg a.i./ha) in H. cajani‐infested fields reduced the nematode density (P < 0·05) and improved plant growth and yield. The densities of eggs and juveniles of H. cajani were 72 and 48% lower in the carbofuran‐treated plots than in the control plots 35 and 52 days, respectively, after sowing. No such differences were observed at 70 days after sowing. The tolerance limit for pod yield in field experiments was 2·6 eggs and juveniles of H. cajani per cm3 soil at sowing time. Grain yield was 20 to 25% higher in the carbofuran‐treated plots than in the control plots. Application of carbofuran protected the roots from nematode damage during the early stages of plant growth and resulted in good plant growth and yield.

Low nodulation and N2 fixation limits yield of pigeonpea on alkaline vertisols of northern N.S.W.: effect of iron, rhizobia and plant genotype

Pigeonpea grown on the alkaline black earths (vertisols) of northern New South Wales often fails to fix detectable amounts of nitrogen (N), resulting in N deficient crops and depressed seed yields. We aimed to solve this problem through selection of plant genotypes that were adapted to these soil types. Selection criteria included the agronomic characteristics of maturity (days to flowering), determinacy and seed size, and symbiotic characteristics of nodulation and N2 fixation. In addition, the interactive effects of fertilizer Fe and N, plant genotype and strain of rhizobia on those characteristics were examined. The experiments reported were sown between November 1988 and December 1990 on alkaline vertisols (pH range 7.9-8.2) at Tamworth, Currabubula and Breeza, N.S.W. In Experiment 1, 108 genotypes were inoculated with Bradyrhizobium strain CB756 and sown at two sites. Nitrogen fixation could not be detected for 86 of the 100 genotypes sown at the Tamworth Agricultural Research Centre and for 51 of the 62 genotypes sown at Currabubula. Six of the genotypes had Pfix (proportion of plant N derived from N2 fixation) values of 10-19% compared with values of zero for five of the six combinations of three check cultivars (Quest, Quantum and Campea)x2 sites. A further five genotypes produced seed yields up to 0.20 t/ha (14%) higher than the average of the three check cultivars. Effects of fertilizer Fe (applied at sowing as FeEDDHA at rates of 0, 0.25, 1.0, 4.0 and 16.0 kg Fe/ha) and N (as nitrarn at 0 and 200 kg N/ha) and strain of Bradyrhizobium sp. (CB756 and CB1024) on symbiotic and yield parameters of pigeonpea cv. Quest were examined in Experiment 2. Nodulation at flowering was increased by as much as 300% by Fe; by early pod-fill, effects of Fe has almost disappeared. Piix values were unaffected by Fe. Throughout growth, shoot dry matters increased with increasing rates of Fe, particularly when N was also applied. In the presence of fertilizer N, seed yields increased with increasing rates of Fe (1.67 t/ha at Fe0 to 2.43 t/ha at Fe16.0). Responses to Fe in the absence of N were reduced. Plants inoculated with rhizobial strain CB1024 outyielded plants inoculated with strain CB756 by 1.0 t/ha (Fe0) and 0.66 t/ha (Fe16.0). In Experiment 3, we examined the effects of fertilizer Fe on symbiotic and yield parameters of 14 genotypes of pigeonpea. There were significant differences between plant genotypes in nodulation, N2 fixation and yields of shoots and seed when fertilizer Fe was not applied and in responsiveness to applied Fe. Seed yields were increased by an average of 0.70 t/ha (108%) for highly responsive genotypes E33, M96, L133 and Campea, but only by an average of 0.32 t/ha (25%) for the low response group (E76, M48, MI44 and Quest).

The effect of compaction on the growth of pigeonpea on clay soils. I. Mechanisms of crop response and seasonal effects on a vertisol in a sub-humid environment

Field experiments were conducted on a vertisol at Dalby, southeast Queensland to investigate the effect of soil compaction on the growth and seed yield of pigeonpea ( Cajanus cajan). Deep ripping and roller compaction were used to establish three compaction treatments which represented the range of conditions observed in commercial fields. Trials were conducted with and without irrigation over two growing seasons (1984/1985 and 1987/1988). Growth restrictions resulting from compaction were primarily related to reduced water uptake resulting from decreased infiltration and storage of water, and restricted root growth. Seasonal conditions, in particular the distribution of rainfall, exerted a strong influence on plant response. Yield reductions resulting from compaction varied from 100% in a very dry season to 0% in a wetter season. The reduced impact of compaction in the wetter season was associated with reduced levels of soil strength during early root growth and a decreased reliance on stored subsoil water for growth. The effects of seasonal conditions on plant response make it difficult to predict the yield reduction likely to result from compaction and to identify a critical level of compaction when ameliorative measures are required. A modelling approach is required to assist in the prediction of yield reductions resulting from compaction and to identify seasonal conditions under which yield losses are likely to be most severe.

The effect of compaction on the growth of pigeonpea on clay soils. II. Mechanisms of crop response and seasonal effects on an oxisol in a humid coastal environment

Field experiments were conducted over two seasons (1986/1987 and 1987/1988) on a coastal oxisol to investigate the effects of soil compaction on the growth and seed yield of pigeonpea ( Cajanus cajan). Combinations of deep ripping and roller compaction were used to establish a range of compaction treatments. The effects of seasonal conditions on plant response to compaction were investigated using irrigation treatments and a rainout shelter to exclude rain during early growth. Despite some reduction on compacted soil, infiltration of water remained high on all treatments and compaction had no effect on subsoil water storage. Plant response was related to the ability of the root system to overcome the soil strength limitations of the compacted soil. The distribution of rainfall during the early growth period was critical in determining plant response. When rain or irrigation maintained low soil strength, compaction increased early shoot growth, presumably as a result of increased volumetric water and nutrient supply. In dry conditions, root penetration was restricted by high soil strength thus reducing water uptake and shoot growth. These early growth restrictions could be compensated by rain or irrigation during later growth stages. The accurate prediction of compaction effects on crop growth and yield requires a modelling framework which accounts for the temporal variability in soil strength, and its effect on root growth and water uptake by plants.

Cassava/legume intercropping with contrasting cassava cultivars. 2. Selection criteria for cassava genotypes in intercropping with two contrasting legume crops

An experiment was conducted to determine selection criteria for cassava genotypes for intercropping with legumes using 18 cassava cultivars which are contrasting in canopy size. Two legume crops were used; one a short-statured, quick-maturing soybean, and the other, a tall, late-maturing pigeonpea. They were sown at 37 days after cassava planting in double rows between cassava rows. Intercropped soybean had little adverse effect on crop growth and tuber yield of cassava, and in some cases it enhanced tuber yield of cassava cultivars with small compact canopies. The effect of cassava on soybean yield was least with short-statured, small cassava cultivars as solar radiation available to the soybean was highest. As the canopy development of cassava was hardly affected by soybean in any cultivars, the selection of cassava genotypes can be made in sole-cropping with selection criteria of high tuber yield and narrow canopy width measured at about 90 days after cassava planting. Intercropped pigeonpea had an adverse effect on canopy development and tuber yield of cassava, particularly of short-statured cultivars. Whilst tall cultivars with spreading canopy were least affected by pigeonpea, they reduced seed yield of pigeonpea to a very low level. It was therefore difficult to determine cassava types suitable for this intercropping. When strongly competitive species, such as pigeonpea, are to be intercropped with cassava, selection can be made initially in sole-cropping with selection criteria of high tuber yield and height which is at least similar to that of the associated crop. The results show that ideal cassava cultivars for intercropping depend on competitive ability of associated species. It is suggested that competitiveness of component crops should be identified using a few cassava cultivars under typical growing conditions before selection is carried out.

Iron deficiency depresses growth of furrow irrigated soybean and pigeon pea on vertisols of northern N.S.W

Crops under furrow irrigation or after heavy rainfall on the alkaline, calcareous Vertisols of northern N.S.W. frequently exhibit chlorosis of young leaves after the soil is wetted, but the specific cause has not been identified previously. The quantitative effects of the syndrome on growth, physiological activity and yield are also unknown. Experiments on soybean and pigeon pea grown on a Vertisol at Breeza, N.S.W., Australia, examined the influence of applying Fe to the leaves, and Fe, Zn, N+P and lime to the soil before sowing, on leaf colour, leaf photosynthesis, crop dry matter, and yield of grain of soybean and dry matter and yield of pigeon pea. In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season. Active Fe and dry matter of shoots were linearly correlated (r2 = 0.76). Soil Fe treatments did not affect leaf photosynthesis, although addition of chelated Fe to the soil resulted in greener leaves than in the control. Foliar Fe had no significant effect on active Fe, leaf colour, or leaf photosynthesis. The 9% increase in grain yield in response to application of 20 kg Fe ha-1 to the soil was not significant. In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%. Effects of lime and zinc were not significant, but N+P increased yield by 112%. The study showed that Fe deficiency is limiting the growth and/or yield of irrigated soybean and pigeon pea on the clay soils of northern N.S.W., and pointed to lime-induced iron chlorosis as a possible mechanism of damage.

Effects of nitrogen supply on cassava/pigeonpea intercropping with three contrasting cassava cultivars

Three cassava cultivars of contrasting canopy size were grown as a sole crop and in intercropping with pigeonpea under two N supply levels to examine whether the effect of N fertilizer was different in sole crop cassava and in intercropping, and whether it depended on the canopy type of cassava cultivar. Application of N promoted plant height and canopy width of cassava in both cropping systems, and this resulted in increased competitiveness of cassava in intercropping. However, when the most vigorous cassava cultivar was used in intercropping, N supply caused excessive top growth with no increase in tuber yield. The yield of pigeonpea on the other hand was always reduced with N supply in intercropping with any cassava cultivar.

CORRELATION AND PATH COEFFICIENT ANALYSES IN PIGEONPEA

Seed yield per plant in pigeonpea showed significant positive correlation with number of plant height, number of branches, number of clusters and number of seeds per pod. Similarly, path coefficient analysis Indicated the importance of number of pods per plant, which had maximum direct effect on seed yield. However, characters like plant height, number of branches per plant, number of clusters per plant and number of seeds per pod affected seed yield via number of pods per plant. Therefore, selection based on early maturity, medium tall plant height, moderate number of branches per plant, number of clusters per plant, number of seeds per pod with more number of pods per plant and medium seed size is expected to improve the seed yield in pigeonpea.

Effects of field slope and duration of furrow irrigation on growth and yield of six grain-legumes on a waterlogging-prone vertisol

The effects of field slope and duration of furrow irrigation on the growth and yield of six grain-legume species were compared on a waterlogging-prone Vertisol (Typic Pellustert) at Narrabri, N.S.W., Australia. The species were soybean ( Glycine max L.) Merr.), navy bean ( Phaseolus vulgaris L.), pigeon pea ( Cajanus cajan (L.) Millsp.), adzuki bean ( Vigna angularis (Willd.) Ohwi and Ohashi), cowpea ( V. unguiculata (L.) Walp.) and mung bean ( V. radiata L.). Field slopes of 1:500, 1:1000, 1: 1500 and 1:2000 were factorially combined with durations of furrow irrigation of 4, 16 and 32 h irrigation −1 in order to vary the severity of waterlogging and assess the relative sensitivities of the six species. Treatments were applied at each of four irrigations. Growth of all species was reduced by increasing the duration of irrigation at the first irrigation, but the more tolerant species became less affected as they developed. Grain-yields of soybean (2.41 t ha −), and cowpea (1.72 t ha −1) were not significantly affected by treatments. However, increasing the duration of irrigation from 4 or 16 h to 32 h reduced the yield of pigeon pea and mung bean by 12%, adzuki bean by 15% and navy bean by 45%. The last four species yielded 2.03, 1.90, 1.14 and 1.18 t ha −1, respectively, at the optimum field slope (1:1000) and duration of irrigation (4 or 16 h). Nitrogen uptake in the harvested grain of soybean (122 kg ha −1) was 2–5 times that of the other species. Reductions in the concentration and uptake of nitrogen of affected species implied that nitrogen fixation or nutrient absorption were inhibited by waterlogging. The study demonstrated that in a semi-arid, sub-tropical environment, a field designed and managed to ensure adequate drainage of excess irrigation water can restrict waterlogging to a period of 1–2 days per irrigation in the surface 0–0.2 m of cropped ridges, enabling sensitive species to survive, grow and produce appreciable quantities of grain.

Response of Five Food Legume Crops to an Irrigation Gradient Imposed During Reproductive Growth

AbstractFood legumes, an excellent source of protein and soil fertility improvement, offer small farmers a means of intensifying cropping on rice lands in semiarid and tropical regions. Unfortunately food legume productivity is often limited by variation in the amount and distribution of rainfall. The study was conducted to compare differential responses of mungbean (Vigna radiata L.), soybean [Glycine max (L.) Merr.], cowpea [Vigna unguiculata (L.) Walp.], peanut (Arachis hypogaea L.), and pigeonpea (Cajanus cajan L.) to a soil water gradient imposed during the reproductive growth phase. Field studies were conducted on Lipa clay loam, an isohyperthemic Typic Hapludoll silt loam soil, using a line source sprinkler irrigation system at the International Rice Research Institute, Philippines, from January to May during 1985 and 1986. Among the five species, peanut yielded significantly higher across the irrigation regimes in both years. Lack of water in the driest regime (50% water deficit replacement) reduced the seed yield of mungbean, soybean, cowpea, and peanut by an average of 43, 39,34, and 32%, respectively. However, pigeonpea seed yield increased by an average of 31% in the driest regime. Seed yield increases per mm of total irrigation water plus rainfall were 3.46 and 5.61 kg ha−1 in soybean, and 3.55 to 5.67 kg ha−1 in peanut in 1985 and 1986, respectively. However, pigeonpea yield per mm of total irrigation water plus rainfall declined 1.53 and 1.27 kg ha−1 in 1985 and 1986, respectively. Peanut performed best in irrigated as well as in rainfed environments, followed by cowpea, soybean, and mungbean. Pigeonpea was suitable only for the relatively dry, rainfed environment. Results indicate the need to match the suitable food legumes to maximize the rice land use.

Dry matter yield and chemical composition of pigeon pea ( C. cajan) leaf meal and the nutritive value of pigeon pea leaf meal and grain meal for laying hens

Three studies were conducted to determine: (1) the yield of leaf meal of pigeon pea in the southeastern agricultural zone of Nigeria; (2) the value of pigeon pea leaf meal (PPLM) as a feed ingredient and egg yolk colouring agent in layers' diets; (3) the value of pigeon pea grain meal (PPGM) as a protein and energy source for layers. Dry matter yields of PPLM were 2.30, 2.36 and 2.68 t ha −1 for 4-, 6- and 8-week cutting intervals, respectively. Crude protein content increased with more frequent cutting intervals and crude fibre with less frequent cutting intervals. Up to 7.5% PPLM in diets did not adversely affect layer performnce, but 10% was needed to give a yolk colour score of 8 on the Roche colour fan in white maize-based layers' diets. At dietary levels >20%, PPGM depressed feed intake and egg production.

Impact of nodule damage by Rivellia angulata on N2-fixation, growth, and yield of pigeonpea (Cajanus cajan L. Millsp.) grown in a Vertisol

Damage caused by Rivellia angulata larvae to pigeonpea root nodules at the ICRISAT center in India was greater in the crop grown on Vertisols (up to 86%) compared to that on Alfisols (20%). Attempts to quantify the field effects of nodule damage on growth and yield of pigeonpea in a Vertisol, involving many heavy applications of soil insecticides (aldrin and hexachlorocyclohexane) failed because the insecticides did not control the pest and adversely affected the growth of the pigeonpea and the subsequent crop of sorghum (Sorgorum bicolor L. Moench). The impact of nodule damage on pigeonpea growth, yield and nutrient uptake was successfully studied in greenhouse-grown plants at three N levels. In this pot study, artificial inoculation with Rivellia sp. led to substantial nodule damage (70%). The results of this damage were a significant overall reduction in nodule dry weight (46%), acetylene reduction activity (31%), total leaf area (36%), chlorophyll content of leaves (39%) and shoot dry weight (23%) 68 days after sowing. At maturity, Rivellia sp. infestation caused significant reductions in top dry weight (22%), root and nodule dry weight (27%), seed dry weight (14%), and total N (29%) and P uptake (19%). The problems and prospects of manipulating nodule damage so as to reduce N losses in pigeonpea are discussed.

Effect of Crop Geometry (Row Proportions) on the Water Balance of the Root Zone of a Pigeonpea and Rice Intercropping System

SUMMARYRice, pigeonpea and rice + pigeonpea systems (in the row proportions of 1:2 and 2:5) were compared. Soil water depletion and percolation were determined during selected dry spells and yields ascertained after harvest. The mean evapotranspiration rates of rice, pigeonpea, rice + pigeonpea (1:2) and rice + pigeonpea (2:5) were 0.28, 0.79, 0.40 and 0.35 cm d−1, respectively, during a dry spell around 60 days after sowing. In general low rainfall intensity and frequent dry spells in the growing season increased pigeonpea yield but depressed that of rice. Intercropping thus ensured yield stability and hence the profitability of the system as a whole.

Productivity of pigeonpea-wheat cropping systems

SummaryStudies on productivity of pigeonpea-wheat cropping systems at the Indian Agricultural Research Institute, New Delhi during 1984–6 revealed that wheat following summer pigeonpea and given 120 kg N/ha produced 4–93, as compared with 451 t grain/ha when it succeeded kharif pigeonpea. Intercropping of preceding pigeonpea with dhaincha for green manure, fodder cowpea and greengram (grain) gave higher yields of 4·35, 397 and 3·68 t/ha respectively than the wheat following pigeonpea alone (3·20 t/ha). Similar effects on wheat straw were also recorded. Summer-sown pigeonpea produced 2·38 t grain/ha without any adverse effect of intercrops. However, kharif pigeonpea produced grain yield half of that obtained in the summer-sown crop. Further, the reductions in grain yield of kharif pigeonpea due to dhaincha, cowpea and greengram were 0·60, 0·52 and 030 t/ha, respectively. Summer pigeonpea + dhaincha-wheat and summer pigeonpea+greengram-wheat proved their superiority over other cropping systems.

Factors affecting growth and yield of short-duration pigeonpea and its potential for multiple harvests

SummaryEnvironmental and cultural factors that may limit the yield of short-duration pigeonpea were investigated over three seasons. Plants in the peninsular Indian environment at Patancheru grew less and produced less dry matter by first-flush maturity than at Hisar, a location in northern India where the environment is considered favourable for the growth of short-duration pigeonpea. However, with a similar sowing date in June, the mean seed yields of three genotypes, ICPL 4, ICPL 81 and ICPL 87, were very similar, at about 2·3 t/ha, in both environments. This was mainly due to the higher ratio of grain to above-ground dry matter at Patancheru. In addition to the first harvest, all genotypes showed a potential for two more harvests owing to the warm winters at Patancheru. The potential for multiple harvests was particularly high in ICPL 87, which yielded 5·2 t/ha from three harvests in 1982–3, 3·6 t/ha from two harvests in 1983–4, and 4·l t/ha from three harvests in 1984–5. The optimum plant population density at Patancheru was 25–35 plants/m2 for ICPL 87, but was higher for the other two genotypes.At Patancheru, the total dry-matter and seed yield of first and subsequent harvests were significantly reduced by delaying sowing beyond June. Generally, the second- and the third-harvest yields were lower on vertisol than on alfisol under both irrigated and unirrigated conditions.The total yield of ICPL 87 from two harvests was far higher than that of a well-adapted medium-duration genotype BDN 1, grown over a similar period. The yield advantage was greater on the alfisol because of the better multiple harvest potential of this soil. The results of this study demonstrate that properly managed short-duration genotypes of pigeonpea may have considerable potential for increased yield from multiple harvests in environments where winters are warm enough to permit continued growth.

Effect of harvest methods on the second flush yield of short-duration pigeonpea (Cajanus cajari)

Short-duration pigeonpea can give up to three harvests in environments with mild winters (e.g. minimum temperature above 10 °C) such as those prevailing in peninsular India (Sharma, Saxena & Green. 1978; Chauhan, Venkataratnam & Sheldrake, 1984). This is mainly due to the short time (about 120 days) taken to produce the first flush, and the strong perennial character of pigeonpea. The seed yield of short-duration pigeonpea in this multiple-harvest system may reach 5·2 t/ha (Chauhan et al. 1984).

Oxifluorfén, un yerbicida potencial para gandules

Tres experimentos con gandúl [Cajanus cajan (L.) Millsp] se realizaron en el Centro de Investigación y Desarrollo Agrícola de Lajas desde el 14 de septiembre de 1983 hasta el 11 de marzo de 1986. En 1983 las aplicaciones preemergentes de oxifluorfén a 1.68, 3.36 y 6.72 kg. i.a./ha. redujeron significativamente (P=0.05) la germinación y la altura del gandúl var. 2,B-Bushy. Sin embargo, la yerba johnson (S. halepense), verdolaga de hoja ancha (T. portulacastrum), el arrocillo (E. colonum) y bejuco de puerco (I. tiliacea) se controlaron excelentemente. El herbicida a 1.68 kg./ha. controló eficazmente la lechecilla (E. heterophylla). La aplicación preemergente de oxifluorfén a 1.32 kg. i.a./ha. redujo la germinación del gandúl, var. Kaki, en aproximadamente 20% en 1984-85 y 5% en 1985-86. Las aplicaciones del herbicida a 0.33 y 0.66 kg. i.a./ha. no afectaron adversamente la germinación, pero las mismas concentraciones le causaron daño severo al tope del follaje al aplicarlo posemergentemente sobre las malezas y el gandúl. Los síntomas de fitotoxicidad desaparecieron a las 9 semanas. Las plantas en todas las parcelas tratadas recuperaron su vigor totalmente. En ambas fechas las malezas gramíneas se redujeron significativamente con las tres concentraciones preemergentes de oxifluorfén más dos aspersiones en directo del mismo herbicida a 0.25 kg./ha. Las malezas de hoja ancha se controlaron en menor grado. En la aplicación posemergente al tope a razón de 0.33 y 0.66 kg. i.a./ha. seguida por una aspersión en directo a razón de 0.25 kg. i.a./ha. no fue eficaz; a razón de 0.66 kg. controló algunas malezas de hoja ancha solamente. En 1984-85 el mayor rendimiento de gandúl en vaina verde (7,989 kg./ha.) se obtuvo en las parcelas tratadas con oxifluorfén a 0.33 kg. i.a./ha. aplicado posemergente sobre el follaje de las malezas y el gandúl, más una aspersión en directo a razón de 0.25 kg. i.a./ha. Este rendimiento fue significativamente superior (P=0.05) a los obtenidos en las parcelas desyerbadas manualmente y en las parcelas testigo sin desyerbar. Con un tratamiento preemergente a 0.33 kg. i.a./ha. se logró una cosecha de 7,826 kg./ha. No se observaron diferencias significativas (P=0.05) en 1985-86 entre los rendimientos de las parcelas tratadas con oxifluorfén a distintas concentraciones y las parcelas testigo. Contrario al año anterior el rendimiento más alto (6,470 kg./ha.) correspondió al testigo desyerbado y el menor (4,428 kg./ha.) al testigo sin desyerbar.