Strong gradients of decreasing soil fertility are found with increasing distance from the homestead within smallholder farms in Vihiga-Kenya. Nutrient use efficiency varies strongly between fields along these gradients of soil fertility. There is continuous accumulation of nutrients in areas around the homestead at the expense of nutrient depletion in further and larger fields. Unequal distribution of nutrients on the farm causes differences in yield with more yields being obtained in some areas on the farm than others.

Nitrogen (N) fixation was estimated for three Acacia senegal (L.) (A. senegal) Willd. varieties (A. senegal var. senegal, kerensis, and leiorhachis) growing naturally in different sites in the dryland areas of Kenya. The quantities of N2 fixed were estimated by the 15N natural abundance method, using leaves as the sampling material. Balanites aegyptiaca (B. aegyptiaca) was selected as the reference species growing in the same area. Soil samples were also collected under A. senegal trees for nodule assessment. Leaf 15N natural abundance values (δ15N) were significantly different between A.

The land question in many African countries has geographical, political, economic, social and demographic nuances. These factors color land and resource rights for pastoral and forest dwelling communities. Land as property draws from the universality of the theory of property in time and space with the earliest theoretical explanations of property being occupation of land and where property belonged of right to him who seized it first. Land therefore represents the earliest form of property and includes resources on the land such as trees; pasture; water and wetlands.

Hoe kunnen veetelers met minder input meer resultaten halen bij snijmaïsteelt? Dat is de centrale vraag van het project “Duurzaam bodembeheer maïs”. De maïsteelt kan echter nadelige effecten hebben voor de bodem door gewasbeschermingsmiddelen en het uit- en afspoelen van nutriënten. Wageningen UR en het Louis Bolk Instituut onderzoeken van 2012 tot 2014 in opdracht van het ministerie van EZ duurzame en praktisch haalbare verbeteringen en vernieuwingen. Teeltsystemen die zorgen voor een gezonde bodem worden daarbij gezien als sleutel tot duurzame teelt.

Recent studies have shown that modern breeding for high yield, visual appearance and long shelf life led to an unintentional decline in taste and the content of essential nutrients in vegetables. AVRDC – The World Vegetable Center is studying whether traditional vegetables are more nutritious than modern varieties and whether early growth stages of these vegetables offer consumers a higher content of phytonutrients.