Optimization of fertilizer performances in long-term garlic cropping soils

Continuous cropping is a common pattern of modern agriculture that takes regional advantages for crop yield profits.Along the progress of mono-cropping continuously supported by intensive fertilizer inputs,such a cropping pattern often undergoes serious problems with low fertilizer use efficiencies and unsustainable crop production.In this study,we dealt with a>25-year continuous garlic cropping system as an example for a problem-solving investigation.These garlic cropping soils underwent problems characterized by loss of soil organic matter,dramatic retention of NH_(4)^(+)-N,and excess accumulation of phosphate and potash chemicals.Through hydroponic simulations,we revealed that the presence of NH_(4)^(+)-N inhibited the root uptake of NO_(3)^(-)-N and K by 68% and 88%,respectively.Despite the traditionally emphasized importance of K,we observed the negative effect of high K on the growth of garlic roots.Further field experiments demonstrated that P and K applications can be reduced by 60% and 50%,respectively,without loss of yield.We thus developed a high-performance fertilization strategy by integrating a recomposed NPK fertilizer formulation to reduce unnecessary P and K inputs,a supplementary application of long-lasting C of woody peat to compensate for the soil C loss,and a foliar K approach to strengthen the stomatal function improvement with K.This strategy allowed a 15% increase of garlic yield and a seasonal soil C profit of ca.1.8 Mg ha^(-1)even at ca.30% lower fertilizer cost.This study would be helpful in managing garlic fertilization and developing compound fertilizers,with broader significance for other long-term cropping soils.

Fertilization and Catch Crop Strategies for Improving Tomato Production in North China

Overuse of fertilizers and the resultant pollution and eutrophication of surface and groundwater is a growing issue in China. Consequently, improved management strategies are needed to optimize crop production with reduced nutrient inputs. Conventional fertilization （CF）, reduced fertilization （RF）, and reduced fertilization with maize （Zea mays L.） as a summer catch crop （RF＋C） treatments were evaluated in 2008 and 2009 by quantifying tomato （Lycopersieon esculentum） fruit yield and soil nutrient balance in a greenhouse tomato double-cropping system. Fertilizer nitrogen （N） application was reduced by 37% in the RF and RF＋C treatments compared to the CF treatment with no significant reduction in fruit yield. Mean soil mineral N （Nmin） content to a depth of 180 cm following tomato and maize harvest was lower in the RF and RF＋C treatments than in the CF treatment. Residual soil Nmin content was reduced by 21% and 55% in the RF and RF＋C treatments, respectively, compared to the CF treatment. Surplus phosphorus （P） and potassium （K） contents in the RFWC treatment were significantly lower than those in the RF treatment, mainly due to additional P and K uptake by the catch crop. We concluded that for intensive greenhouse production systems, the RF and RF＋C treatments could maintain tomato fruit yield, reduce the potential for nitrate （NO3^--N） leaching, and with a catch crop, provide additional benefits through increased biomass production.