Application Of Nitrogen And Irrigation To Pasture To Enhance Dry Season Cattle Production In Uganda

In Section I a review waa made of the problem of providing sufficient a&d nutritious pasturage in the tropics during the dry seasons when productivity is low owing mainly to the leOk of soil moisture and partly due to the generally observed low nutrient content of most tropical eoils* It wee stressed that due to this handi- cup the indigenous cattle take longer to reach maturity and are made more susceptible to various local diseases which lover their lifetime productive performance* Most of the nears hitherto devised to circumvent this problem have, at least in the Uganda environment, offered no overall remedy, or are just expensive* In order, therefore, to maintain high and uniform productivity from pasture throughout the year, this study was initiated to ascertain the role of fertilizer nitrogen and/or supplemental irrigation in bridging the dry season shortage gap* In Section II 2*1 a brief review was made of the past research on Ugaiwda pastures* It was noted that this has mainly been on species introductions from outside the 2 country and selection fro® local and introduced species and varieties for adaptation to different ecological zones under various sanagement practices* The reduction in dry natter and quality yields in herbs ga during the dry seasons was acknowledged* In subeeotion 2*2 th# roleof fertilizer N in pasture production was reviewed. Several workers seemed to agree on its incremental effect* °n the following: herbage dry matter yields} % C*P. and protein yield per unit area of sward; water use efficient? by individual plants} plant uptake of soil N} and herb»g* pal stability* intake and digestibility* Note was »loo made of the forms* mobility and plant uptake of soil Nt the type of N fertilizer to apply, the natural flush ot N on moistening the soil following a period of dry**8* (the Birch effect); the frequency and time of applying 11} hazards that may accompany the misuse of N fertilizers* being mainly over* succulence and lodging inPimnts* diminishing returns and the accumulation of nitrat*-K to toxic levels in herbage* In addition* factors that ®*7 limit response to N were also listed as deficiency of other nutrients and lack of soil moisture*