Sustainably managed irrigated annual crops

Due to large flocks of livestock, fencing often becomes necessary for annual crops, especially if the cultivated fields are located close to roads, or livestock corridors. There are several forms of fencing practised in Tajikistan. Fencing with mesh wire is effective but expensive. Unlike natural fences, mesh wire fences will not create additional income through fruit yields or timber.

Whenever it is possible, natural, local materials (e.g. branches, brushwood, stones, wooden sticks etc.) should be used for fencing. These materials are cheaper than mesh wire or concrete and offer habitats for beneficial insects and other pollinators. Living fences established from local trees and bushes, preferably with spines (hawthorn, cherry plum and barberry) are even more suitable as they contribute to biodiversity and provide firewood and wild fruits.  They, however, may require protection and watering in the first years of establishment.

If stones are available on-site, fencing with stone walls may be considered as well. Natural stone walls are not only durable but also create habitats for pollinators, other insects and small mammalians.

Contour ploughing should be used on steep slope areas. The land is ploughed perpendicular to the slope, alongside contour lines that curve around the arable land. Contour lines favor infiltration of rainwater as water run-off is stopped. So the risk of soil erosion and the formation of gullies is reduced and the availability of water for the annual crops is increased. The soil conserving effect of contour lines can be augmented by planting grass strips, bushes or hedgerows alongside them.

Intercropping is a planting technique that involves cultivating two or more crops at the same time on the same field. Intercropping will result in increased yields as the plants use the available space and nutrients more efficiently and help each other to develop. The associated crops should belong to different plant families, in order not to share the same pests and diseases and to have different requirements on soil fertility and nutrients and extracting them from different horizons of the soil. Intercropping creates biodiversity, which attracts beneficial and predatory insects. As flowering increases, intercropping also favors pollinating insects and thus beekeeping.

There are three basic classifications for intercropping: a) mixed cropping, which involves planting a variety of compatible plants together without any definite arrangement (eg. maize planted together with beans); b) row cropping or alley cropping, in which different crops are planted alongside each other in rows (eg. alternating rows of carrots and onions); c) temporal intercropping, in which a slow-growing crop is planted together with a faster growing one, which is harvested earlier, allowing the slow-growing crop to subsequently occupy the entire planting area (eg. potatoes and pumpkins). 

Irrigation by gravity (furrow or surface irrigation) is the main irrigation technique used in Tajikistan for annual crops. In order to avoid erosion the irrigation should be made by furrows which are following slightly inclined contour lines. The water influx should be slow, so as to increase water infiltration into the soil and reduce the risk of erosion along the irrigation furrow. Furthermore, measures should be implemented to make irrigation by gravity more effective, e.g. by lining irrigation channels with plastic foil for reducing water loss through infiltration or by distributing the water to the furrows by plastic pipes for achieving a homogeneous allocation.

Special attention should be paid to avoid too much watering; excessive water should be evacuated properly as it can cause soil erosion, the formation of gullies or attract pests.

In a gravity irrigation system, it is crucial to break the soil surface between the furrows in order to destroy capillaries and thus preserve humidity.

More sophisticated and efficient irrigation techniques as drip and sprinkler irrigation are economically not viable in most cases in annual irrigated crops.