Soil texture of the rice field was slowly transforming from loam to sandy loam and loamy sand in lower depths below 0.8 – 1 m. Pond was thus draining quickly after every rainfall. In 2013, pond received runoff to almost its full capacity twice but in 2014, it received only once due to lower storm rainfall. However, waterway, pond and rice field channels assured additional water availability to the crop and zero runoff from the watershed. The incoming colloidal sediments with runoff in the pond are expected to clog soil pores with time allowing water to stay for longer time. Part of the sediments received in the pond could also be used as manure in the rice field or elsewhere as necessary. Seepage from An seba river, runoff stored in the pond and irrigation channels and wetness in the rice plots raised groundwater table in the rice field from 3.25 m depth in June end to 1.4 m by 4th week of August, which receded down to 1.7 m by crop maturity . Rate of rise of water table was faster than receding. The water table rose by 1.85 m in about 48 days but receded only 0.3 m in next 75 days.
The water table was oscillating within1.5 ± 0.1 m for about 2 months during grand growth to reproductive stages of rice crop.The shallow groundwater table greatly affected wetness in the root zone. Soil water content in the third week of September showed upward gradient . Whereas surface soil was dry forming cracks, soil wetness below 0.7 m depth was near field capacity and was increasing with depth . Roots of NERICA rice were observed down to 0.8 m and, therefore, parts of the rice roots were receiving water by capillarity from the fluctuating water table and the crop was greener until October . The rising groundwater table due to combined effect of water level in the river and percolation from the pond and rice field may serve as a natural source of sub-irrigation to the rice crop. The crop was harvested in November first week. Although practices to minimize high percolation from rice fields were known and possibilities of runoff farming existed in Eritrea , no systematic efforts were made to cultivate rice due to fear of its high water requirements,nft hydroponic system inadequate rainfall and highly permeable soils. Some experiments were conducted by National Agricultural Research Institution , Eritrea, using NERICA varieties, but conclusions were discouraging. On the contrary, experiments at Hamelmalo Agricultural College under rainfed and life-saving irrigations showed encouraging results . NERICA is a cross of African and Asian rice ,which has been successfully grown in Africa under limited irrigation conditions Inadequate rainfall in Eritrea can be supplemented by runoff harvested as additional water for crop use from >82%non-agricultural lands in the watersheds.
Objective of this study was to optimize soil compaction and puddling intensity to reduce percolation loss and irrigation requirements of rice under semiarid conditions of Hamelmalo. The farm has inputs and outputs.For the purposes of this proposal,inputs are simplified as time, money, and energy; outputs are simplified as produce,heat, and manure. Time and money are considered the conventional costs of production , while energy is the actual caloric input ; produce is the commodity that the farm is producing , while heat and manure are byproducts. Water may be assumed to input with energy and output with manure.In this paper, the example used is of meat production, which for time, money ,and energy outputs meat, heat, and manure. The efficiencies analyzed will be optimized in terms of money vs. Calories .While “money” and “Calories” are not listed as a farm outputs, they do serve as inputs and are therefore appropriate units to use in analyzing efficiency,representing how much useful input can be extracted from a given system’s output. In order to ensure that manure is valued as a nutritious compost, the appropriate metric must be used in optimizing the farming process. If an inappropriate metricis used, farming methods will be optimized without regard to useful recycling of energy outputs, and the value of manure can drop until it becomes a hazard:Public health threats, such as antibiotic-resistant Staphylococcus aureī like MRSA, fecal streptococci and coliforms,and Escherichia coli , have been linked with factory farm nutrient outflows. It has also been shown that carrots and lettuce will uptake tetracycline and amoxicillin, further devaluing manure of the factory farm, making it less likely that the waste is to be recycled for useful applications.Antibiotic-impregnated feed can be avoided by keeping livestock in healthy pastures with shelter: a low-stress, clean environment where exercise is possible and nutritious diet available This harnesses animals’ own immune systems to combat infectious diseases. On pasture, manure is a valuable resource that is recycled to fertilize subsequent years’ vegetation.