Biophysical interactions in tropical agroforestry systems

sequential systems, simultaneous systems Abstract. The rate and extent to which biophysical resources are captured and utilized by the components of an agroforestry system are determined by the nature and intensity of interac-tions between the components. The net effect of these interactions is often determined by the influence of the tree component on the other component(s) and/or on the overall system, and is expressed in terms of such quantifiable responses as soil fertility changes, microclimate modification, resource (water, nutrients, and light) availability and utilization, pest and disease incidence, and allelopathy. The paper reviews such manifestations of biophysical interactions in major simultaneous (e.g., hedgerow intercropping and trees on croplands) and sequential (e.g., planted tree fallows) agroforestry systems. In hedgerow intercropping (HI), the hedge/crop interactions are dominated by soil fertility improvement and competition for growth resources. Higher crop yields in HI than in sole cropping are noted mostly in inherently fertile soils in humid and subhumid tropics, and are caused by large fertility improvement relative to the effects of competition. But, yield increases are rare in semiarid tropics and infertile acid soils because fertility improvement does not offse

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Not AvailableTHE PAPER DISCUSSES OCCURRENCE AND EXTENSION OF RAVINES ALONG RIVERS IN RAJASTHAN REGION AND TECHNIQUES LIKE CLOSURE, CONSTRUCTION OF MARGINAL BUNDS , SAFE DISPOSAL OF RUNOFF AND STABILISATION OF ERODING FACES AND BEDS OF THE RAVINES BY PERMANENT VEGETATION OF GRASS AND TREES TO CHECK THE EXTENSION OF RAVINES HAVE BEEN DESCRIBED. RECLAMATION OF SHALLOW RAVINES FOR AGRICULTURE AND UTILIZATION OF MEDIUM AND DEEP RAVINES FOR FUEL AND FODDER SPECIES WAS ALSO BEEN DEALT WITH.Not Availabl

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Not AvailableA STUDY WAS UNDERTAKEN AT DEHRADUN ON DHULKOT SILTY LOAM SOIL TO FIND OUT THE EFFECT OF VARIOUS DOSES AND DURATION OF GRASS MULCH APPLIED TO MAIZE CROP ON SOIL AND WATER LOSSES AND YIELD OF CROP. MAIZE WAS GROWN ON 8% SLOPE IN STANDARD SIZE RUNOFF PLOTS. TWO DOSES OF MULCH NAMELY 2 t/ha AND 4t/ha WERE TRIED FOR THREE YEARS, 1982-84. EACH DOSE WAS TRIED FOR TWO DURATIONS VIZ. (I) FROM SOWING UPTO 15 AUGUST ND (II) WHOLE CROP PERIOD. IT WAS FOUND THAT MULCH APPLIED AT 4t/ha REDUCED RUNOFF FROM 39.1 TO 14.5 % OF RAINFALL AND SOIL LOSS FROM 22.4 TO 5.0t/ha, WHICH IS CLOSE TO MULCH DOSE OF 4t/ha . THE DURATION OF MULCH DID NOT HAVE ANY EFFECT ON THESE PARAMETERS. IT IS THUS OBSERVED THAT LESSER DOSE OF MULCH @ 2t/ha IS EQUALLY EFFECTIVE FOR CONSERVING SOIL AND WATER ON SLOPING LAND WITHOUT AFFECTING CROP YIELD. EROSION CONTROL PRACTICE FACTOR "P" IN USLE IS 0.22 FOR MULCH @ 4t/ha AND 0.31 FOR MULCH @ 2t/ha.Not Availabl

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Not AvailableAUTHOR SUGGESTS A LAND CAPABILITY CLASSIFICATION SYSTEM FOR THE HIMALAYAN REGION KEEPING IN VIEW THE SOCIO- ECONOMIC , AGRO CLIMATIC CONDITIONS AND EROSION PROBLEMS OF THE REGION. A NEW PARAMETER , NAMELY SOIL: STONE RATIO HAS BEEN INCLUDED ALONG WITH OTHER SOIL PARAMETERS OF THE DIFFERENTIATING LAND CAPABILITY CLASSES IN THIS REGION. IT IS ALSO SUGGESTED THAT FOR DEVELOPING LAND CAPABILITY CLASSES FOR STEEPER SLOPES, SOIL DEPTH AND LAND SLOPE HAVE TO BE CONSIDERED IN COMBINATION , PARTICULARLY FOR THE CONSTRUCTION OF BENCH TERRACES ON SUCH SLOPESNot Availabl

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Not AvailableA STUDY WAS UNDERTAKEN AT DEHRADUN ON DHULKOT SILTY LOAM SOIL TO FIND OUT THE EFFECT OF DOSE AND DURATION OF GRASS MULCH ON SOIL AND WATER LOSSES AND YIELD CROPS. MAIZE WAS GROWN ON 8% SLOPE IN STANDARD SIZE RUNOFF PLOTS. MULCH DOSES OF 4t/ha AND 2t/ha WERE TRIED FOR 3 YEARS. MULCH APPLIED @ 4 t/ha REDUCED RUNOFF FROM 39% OF RAINFALL TO 15% OF RAINFALL AND SOIL LOSS FROM 22.4 t/ha TO 5.1 t/ha , WHEREAS, MULCH @ 2t/ha REDUCED RUNOFF TO 17% OF RAINFALL AND SOIL LOSS TO 6.9t/ha WHICH ARE CLOSE TO MULCH DOSE OF 4 t/ha . EROSION CONTROL PRACTICE FACTOR ,'P' IN USLE IS 0.23 FOR MULCH @ 4t/ha AND 0.31 FRO MULCH @ 2t/ha.Not Availabl

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Not AvailableTHE PAPER PRESENTS VARIOUS AGRONOMIC TECHNIQUES SUITABLE FOR HIMALAYAN FOOTHILLS AND ADVOCATES THAT SIMPLE NON- MONETARY MEASURES LIKE CONTOUR CULTIVATION, MIXED CROPPING , STRIP TILLAGE , MULCHING ETC COULD REDUCE SOIL EROSION AND INCREASE CROP YIELDS SUBSTANTIALLY.Not Availabl

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Not AvailableA TUBING TYPE TYPE RAINFALL HAS BEEN DESCRIBED. THE APPARATUS IS SIMPLE AND PORTABLE IN WORKING . IT CAN BE USED UNDER LABORATORY AS WELL AS FIELD CONDITIONS ON A LIMITED SCALE. WITH THIS SYSTEM , AVERAGE DROP SIZE OF 3.8 mm DIAMETER IS OBTAINED WITH A MAXIMUM FALLING VELOCITY OF 6.4 m/sec.Not Availabl

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Not AvailableBROADLY DEALING WITH RUNOFF CHEMISTRY , THIS SMALL BULLETIN DESCRIBES METHODS OF ANALYSING MAJOR PLANT NUTRIENTS APPLIED TO THE SOIL IN THE FORM OF FERTILIZERS AND ORGANIC MANURES FOR INCREASING CROP YIELDS BUT ARE LOST ALONG WITH THE RUNOFF.Not Availabl

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Not AvailableTHE PAPER PRESENTS THE IMPROVED PACKAGE OF PRACTICES FOR CULTIVATION OF JHANGORA ( MILLET CROP) IN THE FOOTHILLS OF WESTERN HIMALAYAS.Not Availabl

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Not AvailablePERFORMANCE OF FIVE VARIETIES OF JOWAR NAMELY , CSH-1, CSH-5, 302, 604 AND JAI HAVE BEEN EVALUATED WITH A UNIFORM FERTILIZER DOSE OF 70 KG NITROGEN, 40 KG PHOSPHOROUS AND 30 KG K2O /ha . AMONG THE VARIETIES , JAI FOLLOWED BY 604 PRODUCED SIGNIFICANTLY HIGHER YIELDS.Not Availabl