A field experiment on a sandy loam was conducted to evaluate the effects of non-flooded mulching cultivation on the
productivity, nutrient uptake and nutrient balance in rice–wheat (R–W) cropping systems in Chengdu flood plain, southwest
China over a 3-year period. Plastic film mulching (PM) resulted in 12% higher average yield of rice while wheat straw mulching
(SM) led to 14% lower average yield of rice compared with lowland rice under traditional flooding (TF). Biomass accumulation
and nutrient uptake followed similar trends to grain yield. Changes in soil temperature in relation to root growth and nutrient
uptake were likely to be the major factor responsible for the changes in rice yields under non-flooded mulching cultivation.
Compared with TF, PM of preceding rice did not affect the grain yield of wheat, whereas SM of preceding rice resulted in
comparable grain yields of wheat at a lower N rate (60 kg N ha1
) in the wheat season. The system productivity (total yield of
rice þ wheat) in PM was similar to that of TF and higher than that of SM. The yield decline in rice, however, could be partly
compensated by the yield increase in wheat following rice, particularly at lower N rates. Apparent nutrient budgets showed
positive nitrogen (N) and phosphorus (P) balances but negative potassium (K) balance in the TF and non-flooded mulching R–W
systems. Compared with TF, PM led to lower NPK balance due to more nutrient removal by crops while SM led to greater NPK
balance due to more nutrient inputs from straw but less nutrient removal by crops. After 3 years soil organic carbon (OC) and
total nitrogen (TN) were not significantly altered by PM and SM but soil Olsen-P (AP) and exchangeable K (EK) were
significantly increased by SM compared with TF. The changes in soil properties under non-flooded mulching cultivation initially
reflected the nutrient balances in R–W systems. In conclusion, non-flooded mulching cultivation as PM and SM could be applied
to R–W systems in southwest China but nutrient (especially N) management should be optimized in the two systems.
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