Maina Karuiru tends to his avocado trees in his farm in Mathira. PHOTO | JOSEPH KANYI NATION MEDIA GROUP

Most farmers practice conventional farming with fertiliser application and over-production of similar crops across regions, which have yields far below potential productivity levels.
The conventional cropping system has several challenges such as poor ecological diversity, soil and water pollution, soil erosion and loss of soil fertility as well as pests and diseases.
As such, an integrated system of agricultural production is highly recommended. Here there is better resource use from livestock (manure), crop residue recycling, diversified cropping systems (legumes, cereals and agro-forestry), which involves lower use of inputs such as fertiliser, pesticides and high retention of macro and micro nutrients.
Also, increased productivity and profitability will be enhanced by timely farm operations and agronomic practices (ploughing, weeds, pest control and post-harvest operations) which will significantly reduce economic losses and ecological problems.
One must understand interactions between ecology, inputs, residue degradation, cultivation and farm enterprise rotations (crops and livestock), to influence crop and livestock productivity and income at large.
Knowledge on soil health (mineral composition and nutrient available) is key. This should be achieved through soil analysis which gives results quantitatively and qualitatively on quality of soil (type, organic matter content, pH, major and minor nutrients and carbon levels).
The results will equip farmers with knowledge on soil and possible recommendation on whether to amend by liming to reduce acidity, increase organic matter (residues/manures), rotate or leave land fallow to allow complete natural rehabilitation for two to three years.
Importance of incorporating legumes in cropping system is crucial. For centuries, common beans, cowpeas, chickpeas, Fababeans, groundnuts, peas, pigeon peas and soybeans have been used to improve soil fertility by adding nitrogen to it.
Cereals such as maize, wheat, barley, sorghum and millets don’t have this ability.
Also, other leguminous shrubs that fix nitrogen and should be incorporated in the farming system are Velvet bean and Crotalaria. Nitrogen fixing trees should also be included as agroforesty in an integrated system of farming. The agricultural officer around you can advise on these trees.
Incorporation of legumes into crop rotations increases yields of subsequent crops in many cropping ecologies being more in less fertile soils. Beyond the advantage of soil fertility, legumes also offer livestock rich feeds. Crop rotation and intercropping with legumes, thus, need to be frequently adopted.
Apart from use of sustainable inputs such as legume rotation, farmers should use low cost resources and techniques to reduce losses and increase yields.
This include the use of waste organic matter from animals and crops to enrich the soil; pest and disease forecasting through regular scouting; biological and cultural pest control; living mulches as mechanical weed control; conservation tillage (no or minimal tillage and specialised innovative cultural techniques like intercropping, strip cropping, under sowing, trap crops and double-row cropping.
It is important to alternate crops of different root depths to ensure efficient nutrient utilisation. Cropping systems incorporate two main important features; cropping calendar and the cropping pattern.
The cropping calendar shows the duration of each crop grown within the season as well as the planting and harvesting dates. Meanwhile, the cropping pattern, on the other hand, is a rotation plan in which the various crops grown are to follow.
It is advisable to design a cropping pattern for crops grown for more than two years on a given land. This will lead to better yields and increase income per unit area within the specified period by growing crops well-suited to the soil and climatic factors.
This rotation plan factors in the size of land, each crop nutritional and moisture requirement, fertilisation demand for each crop and, most importantly, the sustainability of the farming venture.
This ensures that all resources and inputs (labour, power, equipment and machines) are properly utilised throughout the year to minimise cost of production.
A farmer must have knowledge on the main inputs before he can design fully integrated cropping systems that minimise farm losses due to poor planning, produce good yields and also decrease environmental problems (soil erosion and fertility losses).
This will lead to a sustainable farming practice and management system that will influence overall production and productivity in both short and long term.
Jared Alfred Ochieng and Prof Paul Kimurto are crop experts, Department of Crops, Horticulture and Soils, Egerton University