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Soil acidity is one property associated with decline of most crop productivity. Alfisols and Ultisols are some of the acidic soils predominant in western Kenya. An experiment was conducted in both soils to find out the effect of farmyard manure (FYM) and inorganic fertilizers on maize yield on farmers' fields during wet and dry seasons of 2006. The experiment, laid out in a randomized complete block design (RCBD), had five replications in each soil type. The treatments were: farmer's practice, N (60 kg ha ). During wet season, all treatments in Alfisols gave nearly double grain yield compared to Ultisols. In both soils, during the same season, except for optimal fertilizer, FYM was not significantly (P≤0.05) different from other inorganic fertilizer treatments on plant population, height, cob number, stover, grain yield and 100-seed weight. FYM had a 108% and 103% grain yield advantage over farmer's treatment in Alfisols and Ultisols, respectively. During dry season, plant population, number of cobs and grain yield were higher in Ultisols compared to Alfisols. In each soil type, FYM plus 30 kg N ha -1 provided maize grain yield equivalent to that of N, NP and NPK treatments. FYM had a 4% grain yield advantage over optimal and NPK treatments on Ultisols during dry season. We conclude that larger amount of fertilizers or liming is needed on Ultisols to enhance their productivity to the level of Alfisols and that due to the fact that smallholder farmers are not likely to afford large amount of fertilizer and liming, use of FYM is their best bet for maize production on both Alfisols and Ultisols as there is no significant yield advantage from N, NP or NPK over FYM. Ultisols appear to be more responsive to FYM during dry season probably due to prevailing higher temperatures and relatively dry soil which enhances faster mineralization of organic matter to available plant nutrients. Addition of N fertilizer failed to increase yield in Ultisols, probably due to decline in soil pH and consequently inefficient utilization of applied resources.

Sustainable agriculture seeks to at least use nature as the model for designing agricultural systems. Since nature integrates her plants and animals into diverse landscape, a major tenet of sustainable agriculture is efficiency and lack of waste products in nature. When domestication of crops replaced hunting and gathering of food, landscape changed accordingly. By producing a limited selection of crop plants and animals, human kind has substantially reduced the level of biological diversity over much of the earth. There is more cooperation in nature than competition. Cooperation is exemplified by mutually beneficial relationships that occur between species within communities. If left undistributed and unplanted an abandoned crop field will first be colonized by just a few species of organisms but after several years a complex community made up of many wild species develops. Stability is reached by a community when it has reached a high level of diversity. Diverse communities have fewer fluctuations in numbers of a given species and are stable. The practices which promote diversity and stability on the farm are enterprise diversification, crop rotation, use of wind breaks, provision of more habitats for microorganisms, intercropping and integration of crop farming with livestock production. Intercropping is the cultivation of two or more crops at the same time in the same field. Its advantages are risk minimization, increased income and food security, reduction of soil erosion and pest and disease control. This paper discusses the practice of intercropping in horticultural crop production to promote sustainability. Many crop systems are discussed.

Fruit thinning is defined as the removal of certain flowers or clusters of flowers or individual fruitlets after fruit set and natural dropping have occurred.it improves fruit yield and quality and return bloom for the following year.There are three types of thinning namely:hand,mechanical and chemical.Chemical thinning is the most common type of thinning.Various chemicals are used for thinning.Still many more are being introduced into the market and they have varying effects on fruit quality and yield,depending on the fruit species and cultivar in question.The effects of these chemicals on fruit set is affected by environmental and ecological factors among other crop factors such as vigour.Alot of research has been conducted or is being conducted on chemical thinning but varied results are generated due to many chemicals being released by the chemical companies and varying farmer situations,yet this topic is of immence interest to chemical companies,researchers ,farmers and the fruit industry.This paper discusses the various factors involved in fruit thinning but mainly the physiological principles behind the process of fruit thinning.A lot of research on thinning has been conducted on Apples and other temperate fruits but not on other fruits such as citrus which has worldwide significance.This review will mainly help pomologists who are conducting research on this area.

Studies were conducted at Jomo Kenyatta University of Agriculture and Technology, Kenya to investigate the effect of drying on the proximate composition of crude fibre, crude fat and carbohydrates of two species of pumpkins namely, C. moschata and C. maxima in the year 2006. the treatments comprised fruits with rind and those without rind (fruit pulp), whole seeds and seed kernels, and raw and dry samples (flour). The experimental design was completely randomized and data analysis was by Genstat package. Proximate composition of raw C. moschata fruit with rind was 87.9% moisture (fresh weight), 4.9g/100g crude protein and 6.7g/100g crude ash. The corresponding values of C. maxima were 87.0/100g, 3.9g/100g and 6.9g/100g on dry weight basis. C. moschata with rind contained significantly (P <0.05) higher crude fat than C. moschata seeds. The results also showed that there was significantly (P< 0.05) more crude protein in C. maxima than C. moschata. Similar results were obtained for moisture content. The conclusion is that pumpkin seeds are rich in protein and both species of pumpkin contain high moisture content in their fruits, yielding a dry matter of approximately 12% on dehydration. Pumpkin seeds contain low moisture levels of 5.7%-6.1% making them be stored for longer duration.Pumpkin seeds are a better source of protein hence contributes substantially to the dietary human nutrition. Crude ash content of pumpkin fruits was higher than that for seeds showing that mineral intake in the diet can be enhanced by increasing the consumption of pumpkin fruits.