Benefiting from a weed The weed Gandhejhar (Azeratum conyzoides) abounds throughout the rainy season in the rainfed uplands ("bari" lands) of the foothills and mid-altitude area (600-1500 m asl) of the Western region of Nepal and plays an important role to protect the soil from drying out during the long transition period between the maize harvest and the emergence of winter crops More than 80% of the total annual rainfall (1500 mm) falls from June to September and the winter is accompanied by long dry spells and few erratic rains. Maize followed by winter crops is the area's major cropping pattern. Winter crops, mostly wheat, rapeseeds and barley usually suffer from moisture stress during the whole cropping period from emergence to maturation. To get good emergence of these crops monsoon rain residue is indispensable. Gandhejhar, the living mulch, plays an important role to protect the soil from drying out during the long transition period between the maize harvest and the emergence of winter crops. Maize harvesting ends late September. As yet, the monsoon may continue and the clay-rich soil doesn't allow proper land preparation. Even when the rain stops and the field is ploughed, it is still too early to sow wheat and the bare field may dry out. Thus, until the second week of October (about two weeks after the maize crop is harvested), land preparation is generally not started. Various socio-cultural aspects influence land cultivation. The farm community comprises a heterogenous ethnicity where the Hindu Brahman (Superior Castes) predominates. Women and Brahman male farmers never plough the fields. Bullocks are the only source of draught power and, even so, owned only by about 21% of the families. Families that do not own bullocks could hire them from neighbours or agree to use them paying two mandays labour for a pair. Hindu's great festival Dashain, which is mostly mid October, comes nearer. Hindu culture forbids ploughing during some of the days immediately before Dashain, the annual funeral ceremonies of dead ancestors. Apart from this, ploughing is brought to a stand still in each new moon and full moon and for four days during Dashain. Because of these cultural restrictions to cultivate the land and the uncertainties in getting in the scarce ploughman and bullock pair, planting of winter crops is delayed until mid November. Some families escape these difficulties and manage to sow the crops earlier, but majority of the fields are cropped after Dashain. If these uplands were bare during this long fallow period, large amounts of water would be lost through evaporation. Since there is no alternative source of water supply, not even to meet the requirement of seed germination, there would be a complete failure of crops. Living mulch Fortunately our bari lands are naturally fully covered by Gandhejhar during this fallow period to check the soil moisture evaporation. The weeds are cut out from the lower edges of the terraces when the ploughing starts. Until that day the weed cover is not disturbed but left there to shade the field and reduce evaporation. Though the information about the water balance in the field due to the reduced evaporation and the weed plant consumption is not available, observations show that it is often very difficult to cultivate the very dry soils of bare lands. Moreover, seed emergence is low in these fields. Ploughing immediately after removing Gandhejhar is easy. Moist and clodless tilth is obtained. Winter crops grow there more vigorously. This reveals that the soils of the weed covered field retain moisture for a longer period than those in bare lands. Mann and Singh (1977) suggest to allow weed growth in fallow periods, which, according to them, conserves soil and moisture. Michael and et al (1977) mention that consumptive water use decreases after crops, particularly annuals, reach maturation. Gandhejhar at maize harvesting time is at around maturity stage and being an annual herb, its water use pattern could be in line with Michael's observation on annual crops. Reduced evaporation loss due to the mulching effect of weeds accompanied by a reduced transpiration loss could be the reason that imparts effects on moisture reservation in the field. Use after harvest In addition to the water conservation function, Gandhejhar is used in a variety of ways after being collected from the field. It is fed fresh to ruminants and it is also used as mulch on winter potatoes and in kitchen gardens. It dries there and when removed, it is further used as hay and/or bedding materials for livestock. Either in the form of leftover animal feed or bedding material Gandhejhar also adds, in considerable quantity, to the farm yard manure. But Gandhejhar has disadvantages too. After the third or fourth monsoon shower in June, it comes up densely in the field and severely hampers the growth of maize plants. We turn it down with a spade and the remains are cut and fed to animals. The second flush of Gandhejhar during the tasselling stage of maize crops grows without any apparent detriments to the standing crop. Rather, it later conserves the valuable soil moisture. We love and protect it until the first ploughing! CN Pandeya, Pakhribas Agricultural Centre, Dhankuta, Nepal. ILEIA Newsletter Vol. 11 No. 3 p. 8 References - Mann HS and RP Singh. 1977. Crop production in the Indian arid zone. In: Desertification and its control, ICAR. - Michael AM, SB Hurkeri and NP Singh. 1977. Estimating water requirement of crops. In: Water requirements and irrigation management of crops in India. IARI, Agricultural Statistics of Nepal 1991/92, Agri. Statistics Division. << country/story review