Effects of organic fertilizer application on soil moisture and economic returns of maize in dryland farming

A field experiment (2007–2010) was conducted at Weibei Dryland to determine the effects of different organic fertilizer rates on soil moisture and economic returns of maize (Zea mays L.). Organic fertilizer at rates of 0 (CK ), 7500, 15 000 and 22 500 kg·hm-2 combined with the same rate of chemical fertilizer was applied into field plots. The results showed that manure treatments significantly increased soil moisture storage by 11.49%-21.63% compared with CK; high rate of manure treatment increased soil moisture storage by 9.09% than low rate of manure treatment during maize big trumpet period in the fourth year of fertilization（2010）. High rate of manure treatment significantly increased the average soil moisture storage in 200 cm soil layer by 4.79%-7.65% compared with control. Medium rate of manure treatment had significantly higher average soil moisture storage in 200 cm soil layer by 6.50% than control in the fourth year of fertilization. Manure treatments significantly increased water use efficiency by12.37%-37.55% compared with control. High and medium rates of manure treatments significantly increased water use efficiency in contrast with low rate of manure treatment. Soil conditions were no longer the major limiting factors for increasing water use efficiency with the manure application years increased. It is suggested that medium rate of manure treatment had an obvious effect on conserving moisture and increasing income of maize.