5.5 Guar (Cluster Bean)

GUAR: forgotten crop growing in most marginal conditions many modern applications

Guar - Introduction  Guar is a drought tolerant annual legume that grows in hot, semiarid regions with sandy soils  The major world suppliers are India, Pakistan, the United States and smaller acreages in Australia and Africa  The world demand for Guar increased which lead to introduction of Guar in other countries

Guar - Crop properties  Guar is an upright course-growing summer annual legume (18-40 inches) ( cm)  The deep roots reach deep moisture  Leaves, stem and pods are smooth  The Guar bean has a large endosperm  The endosperm contains large amounts of gum which is the marketable product of the plant

Guar – Some examples of use The gum of Guar forms hydrates rapidly in water into a viscous gel and is therefore used in various products  In Asia:  Beans for vegetable consumption  Crop for cattle feed  As green manure  In the United States:  No calorie binding agent fi stiffener in soft ice cream  In pharmaceutical industry  In cloth and paper manufacture  Oil well drilling muds

Guar – climate and soil  Drought resistant  High toleration of temperature (77 to 95˚F) (25 to 35˚C)  Grows well under a wide range of soil conditions, but preferably fertile, medium textured and sandy loam soils  Salinity and alkalinity tolerant  Soil improving crop  Fits in crop rotation program (with grain sorghum, small grains or vegetables)

Cultivation - Seed preparation  Select seeds with same size and colour  Selected seed must be free from other crop and weed seed  Select seed from the most recent varieties (New varieties are more resistant to diseases)  Inoculate the seed before planting with a special guar inoculant (or a cowpea inoculant)  Plant the seeds in moist soil within 2 hours after inoculation  The seed bed should be free of weed

Cultivation – Seeding date  Plant Guar when soil temperature is over 70˚F (21°C)  Optimum temperature for germination is 86˚F (30°C)  Essential conditions:  Warm seedbed  Adequate soil moisture  Warm growing weather

Cultivation – Seeding and fertility  With row crop planter, Guar can be planted in rows from 36 to 40 inches. ( cm)  Planting depth of 1 to 1.5 inches deep (2.5-4 cm)  Guar requires a high level of phosphorous (22 to 34 kg of P 2 O 5 /ha) and a medium level of potash (45 to 56 lb of K 2 O/ha)  Apply fertilizer before planting and below the seed  Optimum pH value is between pH 7 an pH 8

Guar varieties in USA  Brooks; (1964); first improved variety. High yielding and resistant to major diseases.  Hall; later maturing compared to Brooks. Resistant to bacterial blight and Alternaria leaf spot. Best adapted to heavier soil types and higher elevation.  Mills; Early maturing and also resistant to bacterial blight and Alternaria leaf spot. Lower yields than Hall and Brooks.  Kinman; (1975) a week earlier in maturity than Hall. Highly resistant to bacterial blight and Alternaria leaf spot.  Esser; (1975) medium to late in maturity. Better disease tolerance than Brooks.  Lewis: (1986) Medium to late maturing. Seed yields are approximately 25% higher than Kinman.

Control Measures Weed control Because of the slow growing rate of young Guar plant, weed control is important  Mechanical control:  Do not seed Guar in fields with Johnson grass and other perennial weeds  Early land preparation minimizes weed problems  Chemical control:  Treflan (selective herbicide) can be used to control annual grasses and annual broadleaf weeds Diseases control  Select disease-resistant varieties and high quality certified seed to prevent Guar from Alternaria leaf spot (fungal disease) and Bacterial blight (seed-borne disease causing plant losses) Control of insects and other predators  Guar Midge is the primary insect pest in the Southwest of the USA. Rainfall or sprinkler irrigation may reduce the midge population

Harvesting  Seed pods are brown and dry at maturity  To speed up drying and to kill weeds, Gramoxone (paraquat) can be used  Guar beans can be harvested with a normal grain combine  To clean out foreign materials use a high fan speed  Reels should be set deep enough in the Guar to control stalks (15 to 30 cm ahead of the cutterbar)  For hay: cut crop when first pods turn brown  For green manure: Guar should be turned under when lower pods turn brown  For seeds: after harvesting Guar can be used as mulch when it is plowed under

After harvesting  Income and production costs vary every year and are also depending on soil types  Yields vary from 55 to 360 kg per hectare  Production costs are between 8 and 16 USD/hectare. (depends on fertilizer usage and other production practices

Situation in Pakistan  Guar is poor man’s crop  Only a few guar gum processing plants – that are struggling to survive  Quality issues  Guar processing needs revival and international marketing effort!

Sources of Pictures  Sheet 1 –  Sheet  Sheet 3 - juniper.tamu.edu/Agronomy/guar_pods.htmjuniper.tamu.edu/Agronomy/guar_pods.htm  Sheet  Sheet  Sheet auxiazucar/cyamopsis.jpg